Which Garden Mulch Saves The Most Water?

[@alexgrowsfood]

Now your soils are going to be brimming with water and protected from sun, it might start attracting slugs. You should watch this experiment kzbin.info/www/bejne/ZqmyqqhmjteGacU where I tested which slug barriers worked (or didn't). Happy Gardening!

[@aliceinwonderland7594]

btw. for slugs I use wood ash after burning wood after trimming fruit trees, dried for a month, and other trees around. It seems to inhibit thrips as well.

[@AMPProf]

Now we need a tea time yes

[@craterinahole]

Wow, you made your point quickly and efficiently… thanks for respecting my time, more people on KZbin should take a page out of your book. I’m subscribing now

[@alexgrowsfood]

Thank you so much! It's hard to make videos this condensed so appreciate the comment

[@threeriversforge1997]

Excellent study! I've often said that wood chips are good..... but still allow too much air circulation because of the large chunks not stacking tightly together. As for the grass, use it and rejoice. Not only is it free, but it breaks down faster and is more easily used by worms and such to build up the quality of your soil. I use leaves and grass clippings all the time because that's what's "free" to me, and it makes a world of difference. Even on steep slopes, you can use light mulch and need only add some pegs in the ground to keep the mulch from sliding down. If wind is a worry, place some light sticks on top of the leaves to weight them in place. It doesn't make much, just a few twigs to stop the wind from picking the leaves up.

[@alexgrowsfood]

Thank you so much! Definitely some limitations with my setup (like a lot of the hemp blew away in the wind, and the compost came with it's own moisture) but I think it represents the real-world picture for top/above watering. I like your thinking with air circulation. You kind of want some small gaps within the material to prevent too much wicking from the soil to the surface and I suspect keeping some air locked in place helps limit evaporation too (and stop the soil temperature fluctuating) but you're probably right about wood chips - the gaps are likely too coarse and air can get to the surface and evaporate away. It also comes with a lot of part-broken down material (basically compost) which fills the gaps and probably behaves like my compost test did, pulling the water to the surface. It's cool they had some effect here though because they make great walkway material and the water underneath the paths can still (slowly) move across to the beds. In a real system you'd probably have a mix of mulches anyway e.g. wood chip down the middle with beds covered in thick compost and then hay or leaves and the plamts would drain water from the soil in the beds, so having an extra source under the wood-chip that isn't being transpired by grass is probably really handy. Agree it's amazing that the free stuff works so well but because you have to cut some grass anyway and figure out what to do with it, it kind of seems a no-brainer to use it as a mulch. Direct use seems easier than composting. I've not tried leaves but in windy Cambridgeshire I tend to find clumps of grass don't really get blown around if you give them a few days to dry in the rough shape they came out of the lawnmower in. Haven't tried leaves but it doesn't take much to make them accumulate around objects so it's good to know only a few twigs are what's needed. Quite an interesting topic. I kept the video short for my own sanity during the edit but a lot to be said. Might have to do a few follow-ups.

[@threeriversforge1997]

@@alexgrowsfood You're spot on the money there. Nothing's perfect and we all have to use what we have at hand. I just put down about 4" of shredded Crepe Myrtle around an oak tree in the front yard because it was free to me and either I use it or the landfill was gets it. A nice situation to be in, for sure.While I might not like all those heavy chips, they're weighting down the leaves and are basically "in storage" until I get another bed prepped and ready. Jim Kovaleski did a vid on his use of grass clippings to mulch his garden, and I think he's on to something -- kzbin.info/www/bejne/iXfEiGuvm6xkeK8 And, yeah, watching him will make you want to get a scythe! 😁 Grass gets broken down faster because it's so easy for the bugs and microbes to process, thus boosting the quality of your soil in rather quick fashion. And since you're 'harvesting' the grass regularly, it makes sense to use it. Bark lasts longer because it's harder to consume. Maybe not ideal in every situation, but better than nothing and fantastic for pathways where you actually benefit from the durability of the stuff. There's always something to do in the yard. I give great thanks that I'm still at least a little bit able to enjoy being out there doing things! Thank you for your wonderful content. I'll look forward to seeing what you get up to next.

[@RogerKeulen]

Yes, i also just use what's free. Sometimes is not the quality but the quantity. I make my own compost. But could have more compost for free, if i was able to get it to my place. And for the slopes. I had a sloping garden in my fronthouse. I removed a lot of soil and made some terrases. Only a small part is sloping in full sun. Thats the place that my lavender and all other woody and dry plants live. The rest is just soaking wet in Holland. My soil is extreemly heavy clay. If you can get the water and nutrients in, it will stay there glued to the clay particles.

[@RogerKeulen]

Btw, i live in the south. Thus not the normal "sand" and "tulips" part of Holland under the sea level. I live at a river delta for millions of years ago.

[@RogerKeulen]

What's you soil type and climate ?

[@alainaaugust1932]

Hooray! What’s free on my property is pine straw. The pine trees in the back shed their needles, bounteous and beautiful. When well tired from digging, transplanting, and overall curating my large garden, I sit on the steps near a pile of raked debris, pitch the pine cones and sticks, and accumulate the pine straw. May sound boring but when you’re tired and your legs have had it, sitting with something repetitive is peaceful, like knitting or painting an object when you’re sitting down. Into the lawn cart the pine straw goes. I spread it everywhere, up to the central stalk of the plant and between clumps of flowers. Its reddish brown color contrasts beautifully with the green of plants. Where I live July and August require a good 5-6 inches over the roots of my roses, and when I check I’m always pleased to feel the soil moist but not wet. Over the years harvesting pine straw has saved me hundreds of dollars on mulch, money I’d much rather spend on experimenting with newly purchased plants. Thanks for the sensible video. Blessings.

[@alexgrowsfood]

Amazing. It sounds wonderful. I'm going to have to write this down and think about growing pine whenever I get to own land. And 5-6 inches aligns with what someone else here said about using bark. I can sort of imagine it behaves similarly. If it's free and it works and it displaces the need for buying in nutrients, then it makes total sense.

[@gr8gardn]

I love mulch, especially when it is free/ low cost and readily available. Pine straw is great, especially on moderate slopes where wood chips washes to the bottom of the slope with rain. I prefer pine straw for shrub beds and around trees since it takes years to decompose. I save paper bags/newspaper, chopped leaves and grass clippings for flower beds since they break down over a season and help build quality soil. Papers are laid first, wet down and grass clippings on top. Chopped leaves that have aged for a year are the favorite top layer of mulch in beds. Cardboard shipping boxes are also saved. We can have free wood chips delivered directly from tree cutting companies. It’s not the prettiest but it is wonderful to use on top of cardboard for paths and utility areas.

[@GaiaCarney]

My yard abuts a stand of Ponderosa Pines 🌲 The needle bundles are 9-11inches long. They make lovely blonde mulch for my garden paths and they are _PERFECT_ for mulching my berries (blue, black raspberry & raspberries) Like the loose bark mulch tested by @AlexGrowsFood , I’ve found it doesn’t hold moisture in the soil.

[@user-gh8wt2zi2n]

​@@alexgrowsfoodin the US you can even buy pine straw or needles for the purpose of mulching.

[@lilianashore2086]

that took me by surprise! I wasn't expecting grass clippings to do such good job

[@alexgrowsfood]

It's an amazing result. I unpacked the experiment not long ago and, while it has rained a bit since, there was so much moisture still in there. Still felt like wet clay on the top and stuck to my hand. Hemp was great too but it isn't free.

[@tecmow4399]

That’s fascinating! I wouldn’t have predicted how much more effective grass clippings were than compost or bark. Thanks for sharing ❤

[@alexgrowsfood]

Thanks Tom. Yeah, I was surprised the completely free option did so well. In fairness quite a bit of the lost mass would be have been from the compost/bark but it's a pretty good representation of watering from above and the £5 soil meter (which wouldn't ever lie) seems to back it up. I'm just happy the needle moved in the timelapse

[@flatsville9343]

Thanks for doing a trial with an actual control. The number of so-called Garden experts who do this kind of thing on KZbin regularly fail to do that. Leaf mould is my preferred rough mulch. I will have to do my own trial to see how it stacks up.

[@alexgrowsfood]

No worries. I actually needed the data for my own simulations and even had a bowl of water on a chair nearby as a control too (unfortunately I dropped the bowl when weighing it). Some limitations in the setup - I didn't control for initial moisture level of the mulch. But probably representative of water loss from top watering after the initial saturation had cleared. Imagine leaf mould would do pretty good. I suspect anything that has lots of airy volume to act as an insulative interface would be good. Probably why the grass did well. Imagine a mix is ideal - a nutritional layer for the plants and the worms and then a loose layer for the moisture.

[@tonyparisi6649]

In addition to the very useful information on this video, I just love the enthusiasm of his presentation which made me smile. As a classical musician, I must say “Thanks” for the music which was fun and not overpowering.

[@alexgrowsfood]

Thank you so much for this comment! I spent about a day agonising over the music and almost cut it completely. It's a tough one to get right

[@lynneclark5879]

I use a mixture of grass clippings and leaves which I shred with my weed whacker in a large bucket, works great

[@CherrieMcKenzie]

You provided proof of what I found out trying to withstand the Florida heat. My plants needed watering almost daily until I put in a deep cover of leaf mulch. It did the trick and like you said cost me nothing as I have 5 oak trees that gave me plenty of leaves that I stored over the winter. Thanks!!

[@alexgrowsfood]

It's amazing isn't it? I knew mulch was good but I didn't really have any idea it was this good and what that 80% figure really meant until I did this. I also didn't think compost would behave like that which explains a lot about my 2022 season. The results will be different in the ground where the water can drain right down to the water table but in slow soils like clay it should sit around long enough to be useful to plants. I've not tried leaves myself but everyone keeps saying they are great so I'll get on it too this year (no oaks, just that big apple tree)

[@gardenerguerilla]

Excellent video. You deserve more subscribers.

[@alexgrowsfood]

Thank you!!!

[@kensawka]

Good job on this. Great idea and thanks for sharing it. In Zambia I also have access to rice hauls, peanut shells, leaves and other things I use for ground cover. I wonder if you can do more comparisons with these things as well as plastic, and other items people use to cover the ground (old roof tiles), etc.

[@alexgrowsfood]

Thank you! Honestly these were just the materials I had lying around. I'm not sure where I'd get some of those tbh but I've heard good things about the rice hulls. Plastic sheet might be fine but be careful not to heat the soil too much or limit oxygen transfer and imagine that one would be the most soil type dependent of the bunch.

[@unmeaninglessly143]

Short, concise, with data & graph. I love seeing science & gardening hand to hand. Keep up the good video. Would've love to see more materials tho. Its counterintuitive that hemp (a very absorbent material) performed amazing as mulch. I thought it would've wicked the moisture

[@alexgrowsfood]

Thank you so much! Agree, it's kind of weird. Initially I thought it was best at limiting airflow. I've noticed before that hemp doesn't massively spread moisture - when the chicks knock the water over, only the corner of their pen gets wet. I presume it simply locks water in place (I guess it's cellulose or similar and there is some attraction with the water molecule) rather than spreading it about (I guess compost doesn't bind with it in the same way and instead it creates a suspension which allowed for faster water movement upwards). Just guessing really, I've not really looked into the microscale processes And yeah, these are just the ones I had lying around. Straw and leaves/leaf mulch would have been a nice way of rounding this off.

[@TJTreasuresearth]

This video earned you at least one new subscriber😊 I sincerely appreciate your scientific approach. ❤

[@alexgrowsfood]

Thank you!!!

[@MikeDawson1]

this video came up in my "home" feed, I just subscribed as well because of it

[@alexgrowsfood]

Thanks Mike. Glad you enjoyed it!

[@peppermeat8059]

you can also dig steep hills around your bed so when your watering, the water will run off and collect in the hole where all your plants are

[@robertpowser5624]

It's not a coincidence that the best performance came from the finer ground materials. I use double ground mulch in my beds and it's about 3 inches thick, you do need to look at PH values as tanick acid from bark can be a problem but a bit of lime will help. Enjoyed video.

[@alexgrowsfood]

Thank you so much! Possibly... The compost was a weird mix of sizes really but parking that for a moment, with the true mulches it seems like you're right. Better packing factor and reduced airflow to the soil.

[@Entropicembrace]

Interesting findings! I always felt it odd that it seemed when after applying bare compost to pots it would drain out faster, glad to see there’s further evidence to that!

[@alexgrowsfood]

Yeah it's weird but I guess it's basically soil and has very little clay content so the water can move quite fast through it too. Possible you'd get an improvement in sandy soil in pots if the compost was very stodgy but not in my clay-heavy patch.

[@Debbie-henri]

Wow. This us exactly the sort of experimentation I want to see in videos. Some very surprising results (now thinking about getting that hemp for the new ducklings, when they hatch, and the chickens afterwards). Other channels usually only go so far as recommending bark for the most part, then telk their audirnces they get it for free(I can't!) I've never seen anyone test different mulches before in this way. Would like to see more experiments in the future.

[@alexgrowsfood]

Thank you! I'm not perfect but try very hard not to just repeat things I've heard because it's not as fun for you or me and sometimes the received wisdom isn't correct - the slug barrier test I did in April/May is the best example of that. And I also don't have a supply of wood chips and I try to limit to organic too which only makes it harder to get free stuff. Very glad grass did as well as it did. Hemp is great bedding. Totally worth trying. I've not had any mite issues (in a Nestera coop) and it's quite nice to clean out. And does a good job of absorbing the moisture that the birds leave behind. I've not tried others but they look messier or have other issues. Not the cheapest way of doing it and a little dustier than I'd like but pretty versatile.

[@invisiblesurfer]

Great stuff, very useful experiment, thanks for taking the time!

[@alexgrowsfood]

No worries, glad you enjoyed it!

[@jshkrueger]

The compost entirely depends on how broken down it is and whether it was sifted. A good mixture of chunky and small pieces create a better barrier. Also, if there are a bunch of unbroken small pieces, like grass clippings or tiny leaf particles, it helps a bunch, as well. It's worth noting that compost does more than just act as a mulch. Keeping on the water topic, compost increases the water holding capacity of the soil itself over time. Humic acid will leach out of the compost mulch into the soil, giving the soil more holding capacity.

[@alexgrowsfood]

Definitely agree it'll depend on the compost and tbh it'll also depend a bunch on the soil too. I did try to keep what little structure I could intact but it was basically impossible here. Ideally I would have used a garden bed and tested the mulch in situ but I'm fairly sure one half is completely compacted (and the side that got all the compost a couple of years back is much healthier soil). My biggest concern was the initial water content of the mulch, I should have done a separate test just weighing the loss in each mulch too It's a super interesting topic, if I had more time I'd definitely try more things out. I really just needed evaporation data for a simulation I was running and thought it would be convenient to make a video about it at the same time.

[@jshkrueger]

@@alexgrowsfood Yeah, there are a TON of variables to consider with compost. It's not like bark, grass clippings, or hemp where you have consistency.

[@WouterLockefeer]

This is awesome! I always wonder about these kinds of things and simple experiments like this one are just priceless. Thank you for taking the time to make this video!

[@alexgrowsfood]

You're very welcome! I'm just impressed it evaporated quickly enough for the needle to move on the scales for the time lapse. A really fun setup

[@markm8188]

Nicely done, Alex. Both the study and the video. 😊 This is information I can use!

[@alexgrowsfood]

Thanks Mark! A few shortcomings with the method but these garden experiments are very fun to make. Glad you enjoyed!

[@rubelliterose]

Excellent experiment and very educational! Thank you!

[@alexgrowsfood]

No worries, thank you so much!!!

[@Rebekah-BodyIllumination]

❤❤❤love this. Excellent work.

[@alexgrowsfood]

Thanks Rebekah!

[@apex-lazer]

I just love your energy. Well done brother.

[@alexgrowsfood]

Thank you so much! It's been great to see all the love for this one

[@Orangatangerine]

The biggest factors I see here are colour, thickness of application, and density of the applied mulch. Would love to see a test using deeper wood chips and the same price amount of hemp.

[@alexgrowsfood]

Thickness is a big one for sure. Seems like a lot of people use six inches of wood chips. I tried to press them in like i might firm compost into a bed but yeah, whether that's best or not and for the others too. Also soil type and structure. I tried to keep the lumps together but I don't know how uniform they were. They were pretty coarse with some backfill too but given the clay content it might make a difference. Main issue with that is the applicability to other gardens. I think the relative measurement per inch of mulch is sound but the absolute values will differ. Also the hemp lost a lot of its weight because a lot blew away in the wind. Could imagine slightly different behaviour on a cloudy week with high wind or a sunny week and still days. We had sunny & windy for this run.

[@krazedvintagemodel]

I am pleased to hear about grass clippings doing well in your experiment. I use them because they are here, in abundance, I don't run out, and they build soil structure over time. I garden in ground, no dig, and in pots. Peace 🌻

[@alexgrowsfood]

It's amazing isn't it? Really convenient, can guarantee no chemicals and no need for transport emissions or spending money. A wonderful result.

[@wormfriend5625]

That was such a interesting and informative video. I will be using the grass on my allotment where we have no access to water and I really struggle to get water there. Thanks Alex brilliant experiment.

[@alexgrowsfood]

Great stuff. Honestly, it holds water for ages. It doesn't rain much in Cambridge (lowest rainfall in the UK) but grass is like magic. Was surprised at how flat that graph was but it clearly works even in shallow soils

[@jamiemarsh7439]

Absolutely brilliant Alex

[@deestrawser2423]

Great content! I've been using grass clippings since the 80s and they have always been the best option for my garden. Gardening is expensive these days so free grass and less watering is a win/win. It's also good to find a KZbinr that isn't trying to sell us something we don't need. Best wishes for you and your garden.

[@alexgrowsfood]

It's amazing how good the free option is, isn't it? I had expected compost I bought in to do the job for me when I set up the garden but it was a tough year. I'm not the greatest at making my own compost so this is the perfect use

[@MercifulFamilyFarms]

Great test. Informative helpful and interesting throughout!!

[@SoberOKMoments]

Very good information. Thank you.

[@alexgrowsfood]

Thank you, very welcome!

[@richardwilliams3302]

Very informative video. Thanks for sharing.

[@alexgrowsfood]

No worries! Glad you enjoyed it

[@jooose_5020]

thanku for that experiment!!

[@alexgrowsfood]

No worries! It was fun wasn't it? Glad you enjoyed it

[@Kristers_K]

I generally use geotextiles for weed control, but depending on the type, they don't always prevent water loss, particularly in the cut open planting spots, so this year i use that and a layer of straw on top. I can say for certain that straw/grass seem very effective at retaining moisture in the soil beneath it, as well as maintaining good soil temperature...interestingly enough.

[@alexgrowsfood]

That's really cool. I guess you still get decomposition and nutrients permeating through the fabric and into the soil too.

[@Spiethstar]

Think this is quite a decent study. Thanks for sharing. I'm grabbing what I can to cover the soil. Harvesting grass and other small plants and use a shredder to rip it into smaller bits is helping me in the spring and summer while in the fall and winter I shred branches to make wood chips. The goal is to get organic life in the soil first and eventually the plant should thrive on that soil as well. Don't mind watering the top layer as I'm not a fan of buying something like a irrigation system. Cheers man, lovely vibe you have filming the video.

[@alexgrowsfood]

Thank you so much! Yeah don't panic too much about watering the top, it'll still be better than no mulch. I mainly care because I think I've got a lot of clay and I'm in the driest spot in the country so it takes a while for the water to get deep in the soil. Compost/manure and maybe bark (depending on the mix) would probably be more wasteful if they absorbed more but shredded plant matter should let the water through and, in the winter, I'd worry a lot less anyway if the sun is out less and low in the sky where you are.

[@RFranks]

Good experiment! I put bark chippings at the base of my tomato plants this year and also noticed the ground seemed stayed moist longer than with just compost. I wonder how the different mulches affect the temperature of the soil too, I've heard bark chippings can make the ground slower to warm up earlier in the season which may be an issue for some plants.

[@alexgrowsfood]

I could believe it acts as an insulator, especially compared to compost, but I couldn't say what the net effect of that was. Probably depends a lot on the location and climate

[@gavinbrinck]

amazing content. i'm pretty packed full of gardening channels, but i thought i'd give it a go ! bravo. i really enjoyed the hemp experiment; as well as the bit about grass clippings being okay, so long as they don't have seed ! well done !

[@alexgrowsfood]

Thank you so much! There are a lot of us out there, I struggle to keep up too. Hemp does blow around a lot (you can see the difference in height at the start and the end) and a little pricey so it's very convenient grass performed so similarly

[@gavinbrinck]

@@alexgrowsfood great reflection; cheers, keep it up !

[@Mrs.TJTaylor]

Brilliant! I learned something new. Think I’ll subscribe.

[@Omegawerewolfx]

I use grass clippings or coco coir. I also use ouyas or other related items for water delivery.

[@aliceinwonderland7594]

Bravo Alex, great info well timed as here in Melbourne Australia quite cold atm am keeping soil bare after tidy up weeding etc... for planting new round of veggies and herbs and will use grass clippings as we have it a lot here without any toxic additions. Cheers.

[@alexgrowsfood]

Thank you! Honestly it's such a win that a homegrown item like this is so good. Forget the compost, straight on the ground for organic goodness at no cost but a weekly mow. Sublime result

[@martincooper9982]

Very interesting, thanks for showing your experimenting.

[@TheGiggleMasterP]

Love this! The only suggestion I'd have is to partially submerge / bury the bowls in soil so that it more accurately represents what happens to an in ground garden. At least put it in an actual plant pot that doesn't have clear sides. Excellent video overall.

[@alexgrowsfood]

Thank you!!! You're right though, that definitely would be more representative. Tbh I was more worried about not measuring any evaporation at all. I did a test with water before filming and got 50ml over an afternoon and was too concerned I wouldn't measure anything in soil, let alone mulched soil. It probably makes sense to interpret this data as exaggerating/enhancing the losses over the three days across the mulches for convenience, but I'd be surprised if the relative losses were different in the ground. That being said there are a few other flaws like not accounting for initial moisture in the mulch and of course the results probably depend on the soil type anyway and I haven't (yet) done a soil test - it's clayey to some degree but that's not precise enough to be helpful. Fun yet flawed but I think still helpful.

[@laszloposzmik5829]

Thank you for the informative video! It is like a scientific experiment. Let's try in the next year in my garden,

[@alexgrowsfood]

Thank you! Good luck!

[@mmmmmmmmmmmmmmmmnmmmm]

Silica-based mulchs like straw and rice hulls are great for those who don't want to set up a soaker hose. They're not as readily absorbent as other mulches, plus when they start to break down, your plants may like the extra silica to get stronger!

[@alexgrowsfood]

Very good point. I think, of mine, grass would do best in terms of draining through the mulch but straw makes a ton of sense. It's the one I didn't have lying around otherwise it would have been there instead of hemp

[@innerjon]

Great experiment! Thanks for doing this.

[@alexgrowsfood]

Thank you! Glad you enjoyed it

[@thenaturalhuman9568]

Beautiful demonstration. I’ve been using grass clippings and it got me through a serious drought, almost ten days no rain, with just spot watering.. i was wondering how much the clippings really prevent evaporating

[@alexgrowsfood]

I can believe it! I pulled the grass back the other day and it was still really wet underneath, like wet clay still. Regret not filming it. Amazing how well the free stuff worked

[@MemoryPallace]

Amen bro! You're a natural!

[@alexgrowsfood]

Thank you!

[@YukikoAkazui]

wow this is incredibly informative! i cant believe you only have 1.8k subs for a video of this quality. I'll definitely sub and keep up with your tips!

[@alexgrowsfood]

Thank you so much! It was even smaller a few days ago, that's for sure. Reaction has been tremendous. Thank you (and everyone!)

[@VinInTheGarden]

love the video, mate. I recommend another long form experiment using the same materials but analyzing water content IN THE GROUND with a moisture meter. Cheers! Keep it up

[@alexgrowsfood]

Thanks Vin. Tbh it would depend so much on the soil and distance from the water table and my patch of ground isn't consistent enough. I was really just after evaporation data for some simulations I was running. If I get them working I'll see if I can do something on water content and try and apply it to different soil types

[@dawn9532]

I use cow manure to plant my varigated pittosporum. I’m not sure if it’s a straight manure but my dad bought a huge pile of it.

[@alexgrowsfood]

I've not really worked with manure but I imagine it'd do better than compost in terms of moisture retention if it hasn't broken down yet. And one thing I didn't really talk about was soil structure but if you create an environment that worms like and they work to keep the soil loose and un-compacted (potentially even in containers), then I'd expect you'd see a benefit too. If anyone else can comment and weigh in here, that'd be great.

[@SpringNotes]

Thank you !

[@EdurtreG]

So helpfull! I have a pot garden at S - S.W. on a concrete terrace 1-storey high with extreme winds, so not mulching is certain death. Thank you Alex.

[@alexgrowsfood]

I can believe it, no rain either so you have to be diligent and manually apply the water. I didn't really put two and two together until this experiment so I need to get on it for my strawberries

[@nimajnebrm]

Great video and experiment, though it would be interesting to see how the various mulches affect moisture levels in the ground (as opposed to a container). I have to say I really appreciate the conciseness and length of your videos.

[@alexgrowsfood]

Thank you so much! I put a lot of work in to try and never ever waste your time and to avoid rambling or repeating myself so thank you for saying that. 5-8 minutes is easier to film & edit too. Agree it would have been cool to see the real-world conditions but there are so many variables and I'm not sure what equipment I'd use to measure it (and I really wanted the timelapse of the scales). I spent the last few weeks reading up on vadose zone hydrology and running finite element simulations but I didn't have enough parameters. Soil type and structure have an effect and I don't have a bed that's consistent in that respect over a long enough length. But also it depends on things like initial saturation too (water moves through soil faster in wetter soil) which also depends on your soil type so direct applicability is possibly relatively limited anyway because the parameter space is large. I really just needed the evaporation data for my soil and the mulches so that's the thrust of this video and the conclusion really is limited to 'how well does a mulch change evaporation rates for an almost saturated (predominately-clay) soil surface (and assuming a very very shallow water table). I think if I had access to more soil types and on land away from buildings and underground pipes, I'd be up for it. My main guess though based on the simulations (with incorrect timescales due to parameter issues) is that the excess water would initially go down deeper into the soil and the surface would dry quicker. It would be slow in clay but I'd expect to see an effect still and then I'd expect to see more similar moisture depletion as the soil at the surface can (slowly) draw on water below and from the sides. The (likely) lower temperature would probably slow evaporation too. Basically I'd expect you'd see less of a dramatic change in that graph but the relative losses due only to evaporation would be similar. Sorry that was a bit nerdy but it is a super interesting topic. But the tl;dr is I think the soil type and the location will have quite a big effect and I couldn't figure out how to take good readings of the water content in-ground.

[@MyrtleBeachWebAngel]

Oh I just love these studies! I'm always testing things at home and my bf doesn't even ask anyone when he sees temperature gauges, notebooks, and jars of who even knows what 😂

[@alexgrowsfood]

Love it! Tbh all the best labs are at home & sometimes you really do need bespoke data

[@marksminis]

Finally! Some science to measure which is best! Thanks again Alex great info! ❤ Now I just need to find that hemp…

[@alexgrowsfood]

Thanks Mark! Imo grass is probably better anyway tbh. It's free and doesn't blow away as much or breakdown as fast. No pesticides either

[@marksminis]

@@alexgrowsfood ha, but no grass clippings around here. Grass lawns take up too much water and we live in a desert so everyone has artificial turf 🥵

[@eddieable]

Bloody excellent video. I was surprised by the compost results, although to be fair all compost is made differently and perhaps certain inputs hold water better than others. I'd love to see sugarcane mulch tested in the future. It's commonly used in Australia. I bet it acts very similar to the hay.

[@alexgrowsfood]

Yeah I imagine different composts behave differently. This one was quite chunky, quite woody, but quite broken down. It was peat free and I imagine peat-based will have very different behaviour. One that was composted with a lot of leftover food would behave differently to one from composted with a ton of wood chips and it would depend on the compost duration. I think the main issue is that there isn't a barrier / the interface is too similar while the grass has a lot of air in between and the path for soaking and wicking upwards is more complex and narrower so it's slower. That's my guess anyway. A lot of viewers have suggested the colour difference and the increased sun absorption might be the cause. And yes, I think you're probably right about the sugarcane mulch. Somewhere between grass and straw from the looks of things and I bet straw behaves similarly too.

[@TaLeng2023]

What's your opinion on mulching during the rainy season and how to effectively do it? I read it's preferable to having bare dirt since the soil won't erode as quickly and dirt isn't splashing on the plants and spreading diseases.

[@alexgrowsfood]

I like the idea of never having bare soil so that everything underneath is definitely protected (and insects have a place to nest) but it's hard to do well. This year I let a load of weeds grow and left the dead annuals in place which did some good but has been a nightmare to sort out this year. I think the sensible choice really is to look at collecting leaves (maybe even storing some dry) and scattering them on top. The other option is to under-sow with something like clover that can be removed relatively easily and never really grows high anyway. Or to pay to bring something in - I guess manure in the autumn makes sense if the bed is unused. The main thing is make sure that the soil can still get oxygen and some more solid barriers aren't as good for this. Slugs will love it but my understanding is limiting the amount of bare soil is long term a good strategy for water retention and by covering it with something that breaks down slowly you're more naturally feeding the veg patch. Totally think you're reading the right stuff

[@jacquelineclauson4891]

Great experiment, good to know.

[@jeningle8288]

I'm using Equinola horse bedding, which is rape seed straw. Tony C Smith here on you tube started to use it so I followed on. So far I agree with Alex here, good water retention and the slugs and snail attacks have lessened.

[@alexgrowsfood]

Oh cool! Thanks for sharing. I've not monitored slug attacks but I could believe some of them are better than others. I do organic so from the looks of things I couldn't promote that specific product but I imagine straw is close to grass or hemp in performance. A few others have been mentioned including sugarbeet straw which also apparently do quite well.

[@marthaldyer]

I love the scientific approach:). I wonder how leaf mulch would rate?

[@alexgrowsfood]

Thanks Martha! Hard to say but I would guess leaves themselves would be somewhere in between grass and bark and, over time as it breaks down and looks more like leaf mould, it'll probably start behaving more like compost. Would probably depend on the type of leaf (I suspect different composts would behave differently too).

[@thehuntfortruth]

This is actually a really good video

[@alexgrowsfood]

Ah thank you so much! Glad you enjoyed it

[@bigjohn6458]

now i want to try this experiment with pine shavings and other mulch types.

[@alexgrowsfood]

Do it! I reckon pine shavings would do really well - bark in the worst case and hemp in the best case. It's basically hemp but with coarser particles. I just happened to have these ones lying around.

[@TheRealHonestInquiry]

A great demonstration. It would also be interesting to take temperature readings of the soil. Thanks for pointing out that compost is not a mulch, as I tire of correcting the many experienced YT gardeners that recommend it as such. Anything that wicks water, by definition, cannot function as an effective mulch.

[@alexgrowsfood]

Thank you. Honestly, I had more or less absorbed the information that compost was a mulch and took it as a given which is why I included it in the test series. I did a quick Google to check because it seemed very different but it 'confirmed' it was a mulch. I try very hard not to repeat information without testing it and it worked out here. It had some effect here on final moisture in the core but, given the mass changes were similar, that might be because I didn't fill the no-mulch bowl all the way up or pack the surface as densely as I did with the compost. Agree it would have been nice to see the temperature at the surface and in the core given how sunny it was but it was pretty windy so I presume things were closer to air temperature (c. 20-25C highs, 10-15C lows) than they would have been on still days.

[@ddhqj2023]

I used chopped straw last year and it was great. I used a new bale this year and it's driving me nuts with wheat seeds germinating in it. Not sure what I'm going to do next year.

[@alexgrowsfood]

Sounds like the farmer messed up when harvesting. It's tough to source things well. Probably worth considering elsewhere next year. I try to use on site where possible but appreciate it's not always an option and the timings aren't perfect

[@omegamale7880]

Testing leaves for their mulching effectiveness would have been of interest to me but leaves would come with certain factors to account for such as the size of the leaves.

[@alexgrowsfood]

Totally. Leaf size but also shape and all sorts will affect how much water it traps but also how fast it breaks down or any initial moisture content is released. Compost is probably the same, I just happened to have these materials lying around. Imagine they'd do well though, bark or higher would be my guess but as they break down it'd probably be more like compost/soil.

[@davebean2886]

Thank you for the video and your testing technique! Any chance you or someone else could repeat watering after the mulch has been applied? Also it would be interesting to include a layer of live grass on top for an additional test.

[@alexgrowsfood]

No worries, glad you enjoyed it! I'm not sure how soon but it would be interesting. I suspect a similar set of results though as grass won't be able to absorb as much as the bark and that won't be able to absorb as much as the compost. I sort of expect the compost to be wetter and evaporate earlier and the grass to dry quickly and the excess to get trapped below. Grass or any living mulch would be interesting but you would get transpiration losses too. I really can't remember what I read about it though - if I recall it's beneficial though. Something like clover that fixes nitrogen and doesn't grow too tall is probably manageable, I guess that's why they under-sow.

[@BelindaB777]

Thank you for your experiment, I've always wondered about this 💚

[@alexgrowsfood]

No worries, hope you enjoyed the video!

[@BelindaB777]

@@alexgrowsfood yes It did I've never seen hemp in stores, but I have plenty of grass clippings thanks again...

[@saethman]

Interesting. Would be nice to see this experiment again where you add the water on top of the mulch (this experiment was more of a "evaporation prevention" experiment, would be nice to see if the results would differ from a precipitation-soakthrough-evaporationprevetion experiment)

[@alexgrowsfood]

Yeah I very much wanted to measure evaporation rates to support some hydrology simulations I was running. It's also an easier setup because watering the bowl and waiting for it to seep into the soil is dependent on the mulch but also the soil type and structure and it could be quite slow and differ a lot between areas. We then probably want to look at moisture build up and then it matters how often and when in the day I water the bowls. Agree it would be cool to know the net effect of adding mulch from a top water scenario but I very much chose the simple option (just measuring evaporation for an irregular bottom watering scenario). Might follow up though on water content if I can get my simulation working and apply it to different soil types.

[@daniellapain1576]

Now try mixing everything together as a mulch and try it. I suspect it will do really well or at least hit a middle ground with the rest but with the advantages of also being a slow release fertilizer as it breaks down since there is variety.

[@alexgrowsfood]

I think it would be interesting. I reckon layering would have the best effect so you have multiple interfaces and evaporation would be rate limited by the slowest interface. My guess would be a blend would be an average or skew to the worst performer (I'm just guessing, agree it would be interesting to try). In reality you'd probably have something like a no-dig bed with compost, covered in grass clippings/straw with a thicker layer of woodchip or bark around the edges/through the paths. Much more exciting but harder to test

[@Watchoutforsnakez]

What a nice video. I thought I was soooo great for using compost to mulch. 😂

[@alexgrowsfood]

Same. 2022 was all no-dig beds at half thickness and called it done, but turns out it's very soil-like. Deeper compost will help (water takes a long time to move, especially in clay) but yeah... Compost with grass clippings on top is the way imo

[@artur_pinski]

Great scientific approach. I wonder how hay/straw would perform... Probably, in terms of volume, cost, and water retention, a mix of hay, grass clippings, and bark would perform best. What do you think?

[@alexgrowsfood]

Thank you! I imagine hay would be a lot like grass, I imagine straw wouldn't be too similar but my guess is they pack less efficiently by volume and allow more air flow to/from the soil (and any soaking up of moisture to be faster and more coherent) so I'd guess a little lower. I doubt there is much in it though and it'll depend on exactly how it's cut up. My guess is a mix would promote more evaporation than pure grass/straw (more gaps, darker overall surface colour) but layering might do a better job. In reality you'd probably have something like compost over a bed, with grass/hay on top and using straw in pots and a thicker layer of bark/woodchip on the paths and around trees. Think this is a standard picture and it sort of makes sense really.

[@artur_pinski]

Thank you for replying! I am more interested in mulching around the trees, so mix or layering seems like a better option. Would you mind telling which program you have used for plotting your data? I know a few but do not recognize this one :)

[@alexgrowsfood]

@@artur_pinski No worries. I use matplotlib in Python for all my plotting. I have lots of snippets of code lying around from my PhD days. I swapped the font and use other default/custom parameters so it's not the easiest to spot. The line animation was a crop effect in the video editor though.

[@jeffa847]

I think the light color of the two winners has a lot to do with their success. I grow cover crop over the fall winter and spring and then chop it down and leave it in place and it turns a light tan color and have noticed an improvement in water retention even over the shredded leaves that I used to have in place (I still put the shredded leaves on but they get covered by the cover crop) The light color reflects the sun. Based on my casual observations I think you would see an even greater difference if you were measuring how fast plants used up their water with different mulches. I saw a dryland farmer YT video and I no doubt have these numbers wrong but it was something like once the SOIL gets over 80 degrees 70% of the water the plant uses is just to cool itself - similar to us sweating. I suppose this might be a downside for certain crops that like really hot conditions or in some areas where it is cold but most crops like their soil cooler than it is in most places in July and Aug. I do notice that I have to pull the 2 or 3" of shredded leaves off to top of the soil in the spring to get early spinach going but I can usually pull it back around as soon as they are 6 inches tall.

[@alexgrowsfood]

I could believe it. I specifically decided not to put plants in it to simplify things but my understanding is most water loss is via transpiration. I would like to see how a living mulch compares but maybe that's one for later. Agree colour probably has some impact here although the grey soil and black compost did quite similarly in terms of gradient (evaporation rate) later on so I think much of it is down to the materials ability to transport water. I did try to do a test with water but I made a mess of it but it looked like the heating effect on the soil and compost was present, I just can't confirm for sure. A test in the shade would probably be the easiest way of finding out

[@richardpreston4320]

Great video!! I thought it would be the case...but now we know!! Thank you!

[@alexgrowsfood]

Thanks Richard! I hadn't really considered it before but needed the data for something else. Pretty chuffed that one won though

[@GARDENER42]

I use grass clippings to mulch my 30litre potato containers. best free water retention material there is. Was surprised at how ineffective home made compost was.

[@alexgrowsfood]

Amazing. Yeah it's remarkable. I guess compost is so soil-like that it basically behaves the same and the water transfer at the interface is basically unobstructed - unlike grass/hemp. I did suggest that the compost lost more because it might have had more water initially but it also had less clay content so the water can move much faster, including to the surface. If hemp was free/legal to grow (without an expensive licence) I'd do it but, failing that, looks like grass is terrific and it grows itself.

[@jhouriet]

salt marsh hay is useful here in New England!

[@alexgrowsfood]

Thank you for highlighting this. I'd not heard of that but sounds like a cool option. I really need to travel more, the wildlife you have is so interesting. From the name alone, I was a bit concerned it might soak up salt like samphire being a tidal marsh plant and deposit it in the soil but that doesn't look to be the case at all.

[@Lochness19]

Only thing with grass is if you don't use pesticides, there will be weeds that are shorter and can flower at shorter heights. Do you think cedar mulch and woodchips would perform similar to the bark mulch?

[@alexgrowsfood]

I suspect so although it would depend on the wood and the coarseness and if there is any properly broken down material in there (mine has a lot of compost-like dust). From what people have been saying, they use six inch layers which I expect would bridge the gap between my experiment and their gardens. So use more if you need a better mulch effect. Only thing I'd say about grass is if you mow once a week or every two weeks on a high setting you should be able to get most flowers before they set seed and you can always hand weed lawns rather than spraying. I go around with a hoe and use the corner to lever out dandelions. With the exception of buttercups, the other flowers tend to be easy to pull out anyway, or they fail to spread if cut early so I don't target daisies or anything like that. And general comment for anyone reading this, spraying areas near a veg patch is a big no-no so if you've got grass paths like I do, then hand weeding and regular mowing is usually best.

[@Lochness19]

@@alexgrowsfood The cedar mulch I have has quite a lot of fine material, maybe only 1/4 wood chip sized and 70% smaller, softer bits and fibers and a tiny bit that's fine enough to blow away. I'm trying to work on my dandelions but there's almost as much dandellions as grass and a fair bit of lawn, maybe 4000sf of lawn. There's other weedy flowers too.

[@mr.champlinssciencechannel906]

It probably makes a difference how thick the layer on top of the soil is.

[@alexgrowsfood]

It definitely should. It would act to amplify the differences I suspect (assuming evaporation is mostly/entirely at the surface). I tried to keep them similar here but for bark some people suggest about 6 inches is good. My guess is compost would still struggle unless it was very stodgy. But all of them will depend on the exact composition and material anyway (and probably the same for the soil underneath too)

[@bdogsmom]

wonderful video! very useful information :) thank you :)

[@alexgrowsfood]

No worries, Maureen! Very glad you enjoyed it!

[@bobnewkirk7003]

That meets with expectation. with the lighter colored mulches you will have more reflection of the sunlight so the mulches themselves will be much cooler. the opposite is also true of the compost where the soil surface heated up more allowing more evaporation to occur. likely in your test conditions sun intensity is the primary drying force once you cover the surface with something. you could repeat the experiment with a white construction paper and a black construction paper to test to make sure. great showcase.

[@alexgrowsfood]

Feel like a dump physicist not testing the heating effect due to colour. Probably had an effect although hard to say what the temperature was under the mulch. They don't feel dissimilar to me but I suspect we're getting faster evaporation at the surface due to material structure and material temperature and wind and light. Initially I had considered air temperature and humidity but you're right, locally it would have been hotter in the top layer of the mulch under direct sun. Think if I were to do it again I'd find a shaded spot that still had exposure to high wind. I had assumed that would be the main driver but it would be interesting to see how much each component contributed

[@bobnewkirk7003]

@@alexgrowsfood your methodology is sound. you can repeat the experiment and test any number of variables so long as you keep something at baseline for reference between tests. If you have access to a IR thermometer it might be an interesting showcase during peak hours for sunlight. its entirely possible that the material composition is playing a role which is why I suggested the colored paper test. You could also do different particle sizes with something like Gravel or Wood (plane fines, shavings, sawdust) so long as you can source similar materials.

[@barbaraarsenault1192]

Useful video.

[@alexgrowsfood]

Thank you! Glad it was helpful

[@MatanicFabrications]

Dude you're awesome!

[@alexgrowsfood]

Thanks buddy! Glad you liked it

[@helentc]

Great video! Can you clarify what the hemp is? Is it seed or the hull? Thank yoU!

[@alexgrowsfood]

I'm not absolutely certain but, to me, it looks like they've chopped up or shredded the dried stems. They are very flat, very small rectangular pieces. I've been using AubiChick which is meant to be organically grown and used for chicks and chickens rather than the larger pieces they make for horses. They state they use the 'core of the plant'

[@whereisrenato]

Assuming all the bowls have the same relative evaporation loss, do you think the actual glass bowl somehow alters the way water evaporates? not to mention light has an effect on exposed soil, glass and exposure, perhaps it could cause an unnatural reaction to evaporation. this is just an idea, it's a great experiment i'll do in my garden, thank you

[@alexgrowsfood]

Great question! Yes, I definitely think there is a difference in absolute evaporation here but mainly in that the water can't fall deep into the soil so my soil would remain wetter than if it were in the ground, especially if it was relatively dry down to the water table. The hydraulic conductivity is also dependent on water content so if the water can drain into the soil, I'd expect less evaporation there than in the high moisture content soil in the bowls. Conductivity also depends a lot on soil composition and structure which is very location dependent - and I know my bed gets more compacted as you go along it so it was important to take samples from one area. It's also likely the temperature of the soil would have been lower in the ground than in the bowls and probable that there would have been a slight reduction in wind speed. My goal here was really just to see the relative effect of the mulches on evaporation rate for a given water content in a way that's easy to measure - I needed parameters for a simulation. I think the soil and other local effects probably make getting an absolute number that's applicable elsewhere quite difficult unless I also did a series on soil types anyway. And my understanding of accurately measuring soil moisture in the field is that you need to extract a sample and then bake it and weigh the difference which also limits the number of samples and the method for taking the sample needs to produce consistent shapes and depths. The bowls seemed a more reliable and easy way of getting evaporation rates for the sample sample at near saturation and near-dry. That was a bit nerdy but it's a very interesting topic and there's a lot going on under the ground, it's just hard to quantity and get more general results.

[@dollyperry3020]

Excellent video! I shared it.

[@alexgrowsfood]

Thanks Dolly!

Cool, thanks!

[@kentikxd]

Love your content! I don’t understand why there are so few subscribers and views

[@alexgrowsfood]

Thank you! Ha, I think YT just doesn't love my videos like you guys do. But comments like yours are worth more than view counts

[@garfield7-7-7]

Thanks for this information! Do you think you could do another study showing how much water is absorbed with the mulch already placed on top? I water with a hose so I am just wondering what would allow for the most water to pass through and actually get to the ground 😊

[@alexgrowsfood]

Thank you! This is a really interesting idea, it's just figuring out the practicalities of it. I actually did this one because I wanted to simulate the water content in soil and needed some evaporation data but there are loads of variables at play. One thing that really might make a difference is the soil type (water moves through clay sometimes thousands of times slower than sandy/loamy soils) and the initial water content (water moves slower when the soil is drier). I think it forces the experiment you suggest to be an even spray application of water and then try to capture the initial evaporation step. That probably means more or less taking simultaneous and continuous/minutely readings over an afternoon. Then after a while you'd start to pick up measurements of the evaporation from the soil (which should be slower) - basically you'd see an initial drop at the start of the graph which would be the losses from the mulch and then a slower decline for the soil. It's probably do-able for all of them except the compost and that would get a measurement of the water that didn't make it to the soil. Not sure when but I'll write it down and that's how I would probably do it, if that's helpful for now. My suspicion is that grass would win here because it can't store that much water and it would pass through. Compost could be a dark horse if it's very loose/sandy/loamy in structure, anything peaty or heavy would probably dry out before it got too deep. One other variable is how deep we want the water to go. In my preliminary simulations the water moved so slowly downwards that evaporation dominated everything but my parameters (e.g. hydraulic conductivity) didn't account for saturation making water move faster. A bit nerdy but the tl;dr is mulches where moisture is absorbed really well on soil where water moves really slowly is probably less good than materials that don't absorb much and on light easy to work soils. It's a super interesting topic though and thanks for the idea. It's definitely made the list

[@ProBioMech]

That was an excellent video

[@alexgrowsfood]

Thank you so much!!! Glad you liked it

[@bruce-le-smith]

great video, thank you!

[@alexgrowsfood]

No worries, glad you liked it!

[@RogerKeulen]

I cover the soil with plants.

[@alexgrowsfood]

Tbh this definitely helps too! Still some evaporation losses and some move to transpiration but definitely better than bare soil - even if it's just a living mulch. Another video maybe

[@RogerKeulen]

@@alexgrowsfood I live in Holland. It's summer now and the next two weeks will be rain again. Evaporation is only a problem in full sun or soil that's not covered. Like most modern garden here. They have a large gravel pit (with f**king plastic) or just bair soil with just a couple of plants that you almost can't see. I have a compost bin, but not enough compost. Thus i compost every part of my garden only every 3 years. But when i do composting, it's a very thick layer. I have worms here that have the tickness of my pink finger.

[@terryjones8588]

In your next test, would you put down two or three layers of cardboard under your bark covering. That's what I do for my trees. More videos like this please. Thanks!!!

[@alexgrowsfood]

Thanks Terry! It's a good point and cardboard will probably help a bunch. I think in real systems it wouldn't be as simple as this anyway - the compost would probably be over cardboard too for no-dig and you might even decide to put grass on top of that. Also layer thickness will have a big effect on bark/grass/hemp/leaves and some effect on compost. I think what you are doing for your trees is probably perfect. There's someone here who uses 6 inches of wood chip, if you're doing that you're probably doing plenty. The exact behaviour will probably depend a lot on your soil type.

[@xperimental1974]

is that because hemp mulch has less big pores compared to barks/chips? so water is not easily loose through small pores?

[@alexgrowsfood]

I think so. My guess is either water can't transfer vertically as fast because it has to transfer between linear grains (mostly within the material) or the air can't get to it so humidity around the grains are high and evaporation stays low. I think that's why grass did a little worse than hemp but much better than bark. The main counter arguments are colour: hemp is white so potentially a lower temperature at the surface and evaporation slows and also the bark had decayed slightly so had some soil-like / compost-like material in it and because those particles are so small you get a different dynamics (I think the water moves externally to the material - like a suspension or via surface tension on a microscale and can move pretty well in all directions). It's been a while and I've not looked into the microscale mechanics in that much depth but that would be my guess.

[@homesteadknowhow]

lighter colors resist heating up. That can make a big difference. Legitimate compost works best when naturally incorporated into the soil, not as a single layer on top. Wood mulch tends to work alright, but it does best with a lot more volume because its large pieces don't catch evaporating water very well. I mulched my garden with hay this year. I acquired 100 bales of moldy alfalfa/grass hay and it's done pretty well. I've never seen so many worms and nightcrawlers out there.

[@alexgrowsfood]

Agree, didn't really think about it at the time, although I think the high wind and ambient temperatures played a good part. I think the main thing is how much easier it is to get a hold of grass and it worked so well. How thick do you mean when you use bark? I was pretty happy with the inch in the bowl, but imagine loss is proportional to thickness. Definitely see why people use it in their walkways

[@homesteadknowhow]

@alexgrowsfood When I use wood mulch (usually fresh arborist chips) I use 6 inches at a minimum. At that depth, it's really quite hard to beat the benefits to soil function and healthy soil biology. I personally don't use grass clippings because I only cut my grass about 4 or 5 times a year (2 to 4 feet tall) and use it for animal feed and nesting material. With grass clippings, a thicker layer tends to mat together and choke out the soil causing too little airflow for healthy garden soil. Grass clippings are best used not much thicker than an inch or two around your plants.

[@homesteadknowhow]

@alexgrowsfood When I use wood mulch (usually fresh arborist chips) I use 6 inches at a minimum. At that depth, it's really quite hard to beat the benefits to soil function and healthy soil biology. I personally don't use grass clippings because I only cut my grass about 4 or 5 times a year (2 to 4 feet tall) and use it for animal feed and nesting material. With grass clippings, a thicker layer tends to mat together and choke out the soil, causing too little airflow for healthy garden soil. Grass clippings are best when used not much thicker than an inch or two around your plants.

[@P.I.E.]

The problem I have with using any kind of mulch is that I like for my seeds to sprout naturally. I prefer no mulch in my containers. It allows me to re seed and also to notice any issues with the soil.

[@alexgrowsfood]

Yeah, this can be a bother. In principle the grass can break down so by next season the seeds should find their way to the bottom but it's probably going to be less reliable than directly coming into contact. Might be worth an initial mulch early in the season and not topping-up and leaving it to decay/thin out by the autumn. I've not tried it but could be worth experimenting on a small area

[@P.I.E.]

@@alexgrowsfood all I have is containers (for now). Plus, I tend to over-seed. It works for me. I would also be interested in a larger scale experiment.

[@lynnevans7248]

This is great!!!😊

[@alexgrowsfood]

Thank you so much!

[@MrDjafal1]

@Alexgrowsfood how is sand in comparison, could u please test it ❣

[@alexgrowsfood]

I'm not sure about sand. It gets quite hot and is quite small so good at restricting airflow but it also soaks up water. My guess would be it doesn't do as well as the top two and it won't feed the soil. If I do another set I'll write it down but it would have to be a complete set to account for the weather which is the main driver.

[@BroqueCowgirlHomestead]

@Yogi Hollow Farm interesting.

[@GaiaCarney]

Thanks for creating & sharing this @alexgrowsfood 🌱 I have a stubborn family member, set in their ways, who is anti-mulch!? Their garden soil is as dry as talcum powder 😵 Perhaps your video can help . . .

[@alexgrowsfood]

No worries. There are a few limitations with this experiment which may affect applicability to your garden - being in a bowl, using my clayey soil, breaking the soil structure to test, initial moisture content of mulch and soil etc. but the relative evaporation rates (the gradients on the graph) should hold true, especially towards the end of the experiment. The best thing to do is a side-by-side test. Find a 1m patch and cover it with grass, wait for a sunny forecast and then water it and check the moisture each day. There will be some water transfer horizontally under the ground but the difference should still be pretty compelling a few days in. You can use a moisture sensor or you can dig it up, weigh it, bake it till dry and weigh it again, or I suspect even just touching the surface and a few cm down will be enough.

[@mariannerogers8003]

My friend puts hay over her garden. Soil stays moist but also houses a HUNDREDS of slugs which come out of the hay at night and eat all her plants. I use grass clippings, which shade the soil but light enough to not encourage slugs. If you use a heavy layer of hay, I suggest, that you invest in slug pellets or you won’t be harvesting much after the slugs dine on your food.

[@alexgrowsfood]

Thanks Marianne. You're right about that but I tend to find slugs will make a home in anything wet that isn't exposed soil/compost. Although it has been a terrible year for slugs - I went outside with a torch on Friday night at 11pm after a week of scorching heat to find my phone and there were hundreds in the grass. One of the downsides of preventing the surface from drying is that you create that nice moist habitat. Imagine bottom watering via a soaker or drip hose is better but won't eliminate the problem either. While they probably do work very well, I can't advocate pellets and normally just accept a certain number of losses but thinner mulch layers are one approach for sure. Otherwise you might want to delay planting until your plants are substantial and are less appealing or more resilient to damage. I also tested several slug barriers like copper and wool here kzbin.info/www/bejne/ZqmyqqhmjteGacU although the results were mixed.