Greenhouse Passive Heating (Does it Work?)

[@jeffjones9792]

I have constructed compost bins in the greenhouse. The rotting compost warms up during the seasons. Pots and boxes of plantlets on top of the compost - free heat, plus potting compost at the end of winter. I'm 78, my dad taught me this when I was a kid, goodness knows how old the idea is.

[@Iz0pen]

Does it smell or off gas ammonia?

[@Spotty-bugle]

@@Iz0penno it shouldn’t if you do it right

[@AndrewUnruh]

Very clever idea.

[@marytwombly8212]

I have a greenhouse up at 8600 feet in the foothills. I had to give up on peppers and tomatoes a while ago, but I am still successfully growing and harvesting bok Choi and lettuces- its given me a wonderful fall season of growing

[@wybuchowyukomendant]

I have 10 meters of pvc pipes 2 meters below the greenhouse, with a little computer fans pumping and sucking the air on both ends just to help a tiny bit with the airflow, and last winter it didnt go below 11c inside, even when there was -21 outside, highly efficient stuff.

[@dlobane8860]

awesome content, one thing I did was use Aquarium heaters in my 50gal drums of water to help with overcast days and colder nights. I managed to grow good number of things last winter in Colorado with minimal increase on electric bill :)

[@kevintheweedman]

I was thinking about doing the same thing. And if it gets extremely cold, put a heater in there.

[@borisjurosevic177]

What were you able to grow during the winter ?

[@DunRovinRanch-1969]

I think the aquarium heater is the way to go to get past those cold cloudy days.

[@jimmybamslam]

Awesome video. As a Canadian viewer, I appreciate that you made a point of showing the Celcius readings.

[@kobbyd7949]

I use black IBC- Containers in my greenhouse. When you buy used ones (food proof) that's not so expensive. They do a great job. But I have additional insulated the north-wall and parts of the east and the west-wall with reflective bubblefoil. When we did that last winter, we felt an immediate improvement.

[@kburkes4245]

Great video. I use a small heater below 40 in my greenhouse on very cold nights, and I may add some black water jugs. I don't have the option of pavers or gravel, but I imagine just the jugs will help some. I also have incandescent Christmas lights -- they put of a pretty good amount of heat too.

[@Power_Prawnstar]

You have great hair for an old bloke, I have an ever diminishing mop, but my beard is much fuller and browner than yours, would trade it for the mop though. Lucky bugger. Love the metric conversions, makes watching the vids even better, thanks Scott.

[@revk8611]

Thank you for this video. I do appreciate the celsius temperature on the screen. Being in Canada, it helped me get right to the point. I want to build a greenhouse next year. Excellent job

[@steve_frenchcougar1747]

you can also put a platic bin over your plants to make a greenhouse in a greenhouse but it not enough light but still good for salad and spinach

[@simplifygardening]

Such a great way to heat. I have 2 1000 Litre IBC containers of water in my tunnels and they are really helping the heat remain through the night. Great video mate and such a good thing to pass on to others

[@MikeKincaid79]

Cool videos, Scott! I've been watching all your greenhouse videos and I love how you give all this information about the temperatures inside and outside. Love your water battery design!

[@smitty9999]

Perhaps you could add a temperature probe and logger to the water in one of the barrels and then track the temperature change over time

[@GardenerScott]

Thanks for the suggestion. I've thought of doing that as part of my next heat experiment.

[@gregoutdoors7]

I have a 12x7 foot homemade cattle panels greenhouse. I installed two 55 gallon barrels of water, painted black like yours. It does work. I mess with solar panels some and considered installing a couple of 12 volt heating elements into my barrels, hooking each of them up to a 100 watt solar panel. It would heat the water even hotter during the day. I wouldn’t use them in summer because they wouldn’t be needed then. Only early or late in the year. Thanks for ur video 👍🏻

[@matthewfarrell317]

This was very interesting. We dont get cold like that here in Melbourne. That said i overwinter my capsicums outside with no protection and some of the varieties fruit during winter. Coldest we get is -2C maybe once or twice, and -1C a few more times. Average maybe 4 to 5 at night and 10 during the day in the depths of winter. I have seen people use aquarium heaters..... and compost piles

[@waynesell3681]

Great video! Glad you have your greenhouse to enjoy year round gardening. Even at 16 degrees outside and windy. Super setup!

[@arkaisk2]

Just the right video for me here in southern Sweden. I'm doing the same experiment, with one small greenhouse in the middle of a lawn, and another small mounted to my house facade. Both facing South. We've had a couple of nights just below zero Celsius, but with black buckets I've manage to keep every plant alive so far. And, of course, the plants I grow in there are sturdy against the cold. Fun projekt 🙂

[@lavernabouzspain]

August 2024. Hello Gardener Scott. I'm in zone 9a Pacific Northwest a normally cold and rainy area, which came in earlier than it has in years past. I'm trying to become at least 87% less reliant on the store's vegetables, so I'm trying to greenhouse through the Fall, Winter and into the Spring of 2025. Thank you for this informative video. It gives me a lot of insight of what I could possibly try doing. I have not tried the passive heat method, but I think that it might be a better alternative than my oil filled radiator, which is doing well on the 1 Setting, along with a Dust to Dawn setting of on 2hrs off 2hrs for the cool nights that are now present. However, I think I might do better with passive heat and try setting the radiator heater aside. I'm going to look at where I can place several smaller black jugs and tubs. Thanks again for the insight. God bless!

[@DustyTail]

Paint your bench top black. Also, wind would make a big difference. Wind with cool temps can cool the greenhouse down as much or more than low temps with no wind.

[@marsilt]

also pavement is relatively light. But it would be fun walking on it in hot summer day :D

[@johnc7206]

I use an aquarium heater in my water container and it usually keeps it above freezing in my small mini greenhouse. They are usually between 25watt and 100 watt so use minmum electricity. As my greenhouse is so small I only use a 25w one and it seems to do the job. I am in SE of UK so temp in winter is rarely less than minus 5 C.

[@julie-annepineau4022]

Great info, thanks. Also good to know my region isn't the only one getting unseasonably early cold in a longer stretch than usual.

[@teresashearmire3094]

I put a heavy black canvas on the north wall of my greenhouse. However, I do run an extension cord for a 250w brooder lamp for heat.

[@foxnoxness4989]

Ohhhh just what I needed, I'm jumping right into it! ❤

[@naturnaut9093]

excellent! buffering the cold by passive heat

[@heidiclark6612]

Very informative experiment! It’s amazing how good passive heating works!

[@amygilbert8429]

In the South, so we wouldn’t need the heat for as many months as in CO. Once the sun comes up, the temps rise above freezing rather quickly. I think that I would start using the water in the barrels in the Spring here and then refill them before the first freeze.

[@GrowCookPreserveWithKellyDawn]

We just put up a Planta 10x26 Sungrow this year. Heating has been a challenge during the unseasonably long cold spell in my Ohio Zone 6b region. This year I hope to incorporate as much passive form of heat production as I can, in addition to natural gas, which is very economical in our rural area. Our water table is a bit too high for typical geothermal solutions, but we are exploring alternatives. Thanks for the insight!

[@SjMk1.]

Neat! Cheers for ideas - maybe combined with raised beds and a raised + insulated floor (pallets stuffed with polystyrene on gravel base) + horticultural bubblewrap.

[@lindaferguson593]

Im planning on a sort of walipini above ground, surrounded by bales of straw stacked at 2-3 high and 2 wide. Thus mimicking the idea of being an underground application.

[@SherryEllesson]

Scott, thrilled for you that you've been able to find out the capacity of your water heat source. If you don't already have it in your library, you may enjoy a book titled the Year-Round Solar Greenhouse by Schiller and Plinke. fwiw, inexpensive little hot-oil heaters that don't take much electricity would probably run off a solar panel even with low solar gain to extend the season a fraction more.

[@GardenerScott]

Thanks! I don't have that book but will look into it. I will be experimenting with some candle heaters and similar methods.

[@SherryEllesson]

@@GardenerScott Oil lamps burning odor-free liquid paraffin generate quite a bit of heat.

[@shineyrocks390]

Scott i used Charles Dowdings hotbed method inside my greenhouse and it works well. By doing this Im also making compost plus heating the greenhouse at the same time.

[@TRguy64]

Probably has been said, but whatever areas do not receive much of any winter sun is a good place to use that foil bubble wrap stuff to insulate and reflect heat back in. Also drape another layer of plastic or even again that foil stuff on the gable ends, these doors certainly are not all that airtight.

[@FASTBACKKAT]

this encouraged me to a new greenhouse im getting, im gonna heat with barrel water ,might keep a heater out there if it gets super cold but we have had some pretty mild winters in missouri last few yrs..

[@eliandkate]

This was great to see, it’s amazing the difference your barrels made!

[@budj13]

This is a very informative video and shows the power of the thermal mass for heat storage. For me, I've run electricity to my greenhouse so I can couple supplimental electric heat to deal with the extended cold periods. I am learning a lot fhis first winter with my greenhouse. We had some very unusual cold early this year, too. Our first frost came almost 3 weeks early and we dropped to 24F in October-- unheard of historically. So, keep sharing your experiments and I'll learn from you in parallel to my own data. Thanks!

[@WYO_Dirtbag]

I've been building a sunken cold weather greenhouse in my zone 5B climate the past few months. I will have one wall of 16mm triple wall poly carbonate sheeting at a 38.8 degree angle facing south, with the rest being solid insulated walls. The sunken part is only dug down 24 inches, but I poured footers and laid 8inch concrete block. I plan to add the back wall lined with 55gallon barrels of water, have a compost pile for the winter months, and experiment with building a passive water heater with a solar powered pump to warm the barrels during the day. The other key will be having foam bubble insulation to roll down to cover the polycarbonate wall at night when it gets down to the single digits or negatives. I do have power and will have a heater for those double digit negatives.

[@WYO_Dirtbag]

The greenhouse is 10x20. I'm also wanting to make expirement with circulating the warm water heated by passive water heaters though pipes in the soil in the raised beds. Get the soil itself to also hold heat. I did put foam insulation around the block to try and also keep the frost from creeping through when we hit the severe cold. But I am hoping for year around gardening in this thing. Along with the heat, the other issue becomes the lack of daylight in the dead of winter. I think I'll have no other option but to use grow lights if I want to try growing tomatoes and cucumbers. Otherwise growing greens like kale would be a safe option for the dead of winter.

[@danielanac5093]

In conclusion it' s not necessary.I say it like an option to increase the temperature in storing heat elements.Thank you for your explication and inspiration :-)

[@honeydew4576]

Gardener Scott: This is completely off-topic, but I wanted to get this message to you. I watched a couple of your leaf mulch videos and loved them. I discovered something amazing today and wanted to share this Good News. In April this year (2023) I tried an experiment. I put a shallow square bottomless wood frame on the ground. The frame is about a foot high. I filled it with leaves and watered it in. Then I put down thick black plastic that I cut holes into for drainage. I put soil on top of the plastic, filling the square frame, and planted onions. After harvesting the onions today, I removed the soil, lifted the black plastic and discovered rich, fully broken down leaf mulch. Not a sign of any unbroken-down leaves. Just that rich black gold! I was astonished at how quickly The Lord created that mulch, and wanted to share this idea with you and others. God is good and He gives us the best ideas!

[@GardenerScott]

That's a great way to get that black gold.

[@jasonmann5019]

Fascinating video Scott. Great sharing and thank you. Jason from Melbourne Australia.

[@afmedwards]

Best video on Greenhouse Passive Heating I've found thanks

[@GardenerScott]

Thank you!

[@StaceyG-l6m]

We get snow before Holloween now! We did the last two so cold now Spring Windy up to 50 gusts and Hail Z& thunder big drops pushing camper around!

[@KodaCoplayer]

I had this idea and had to look up if it worked. I’m planning on a mushroom enclosure indoors and I have my pepper garden greenhoused, but couldn’t get any heat retention. Thank you for the video!

[@finlaymorgan1405]

I just wish my greenhouse was big enough to have space for water tanks instead of more tomatoes, i hve instead sealed it to the neighbour's wall to increase the thermal mass, i will see how it fares this winter

[@KayWessel]

Very interesting! I live in Skien in Norway which is in the same zone, but not as cold just now. Only -2C now. I guess it would be possible to extend my growing period by 1 month by insulating the outside with some thin insulation during the night. My compost is still running at 70C, so it would be possible to exchange some heat from the compost. It depends how long this cold period will last. If less than 5 days I guess it could be possible to keep the plants alive during the first cold period.

[@aloras405]

I want to get a greenhouse but I want to be able to heat it through the winter so I can grow in it all year. I will have to do two different heating systems. I will have a a passive system but then for those cold stretches, I will have an active heater.

[@GardenerScott]

That is a good approach.

[@StaceyG-l6m]

In Spk.,Wa. Want a green house & I’m going to do it after new camper going to re do old camper so love these green house shows!!✅✌️❤️🙏🌍🌈😎

[@bennaylor1988]

Scott, great video and excellent insights. Interested to know what your plan is for the water barrels over winter. I too live in an area with extreme winters (Souther Ontario, Canada), and am curious if you will drain the barrels completely and refill in spring, partially drain, or feel the volumne of water will take too long to actually freeze that it'll be ok in the greenhouse over winter. Thanks again for the content.

[@GardenerScott]

Thanks! I'm planning to continue monitoring with the barrels and jugs filled. Because it takes so much energy to freeze water, I'm not too worried. In a previous greenhouse, a 1500-gallon open tank never iced over even when the air temperature was below freezing.

[@jennaandparkerstaggs1113]

Hey Scott- I love your content. I have a green house, a outbuilding type with clear corrugated plastic for the roof and upper walls. This is my first winter with it. I’m thinking of adding a “layer” of thick mil clear plastic on the inside to possibly trap some air between the plastic and the structure. To be able to reuse it, hopefully, I’m planning on lining the edges of all the plastic with tape, and then will tape up the plastic sheeting. If that doesn’t work I’m going to staple it on. We will see if it works!

[@GardenerScott]

Thanks! Adding a layer of plastic can trap air and be a better insulator. Good luck.

[@JackieHorsley-z8s]

I enjoyed your video I Purchased a hoop house this year I have not really used It very much just Mainly for storage I have Decided Iam going to try to over winter some plants In It this year I think I am going to try the water Bottle method so fare this fall we have had some really warm Temperatures that have been Sticking around so If I am going to try the water Bottle method I guess I better get on It lol.

[@auntieclimactick]

I just found your videos and they are just what I was Looking for! Thank you so much for making them. I am in NC in zone 8b, I moved here from Ohio zone 6b. I was really looking forward to gardening in a longer season but omg it gets pretty hot and the bugs get SO MUCH BIGGER because they also have a longer growing season! Yikes! Reality has taught me some hard lessons in comparison to my “longer gardening season fantasies”. So I do finally get to have a fall or even winter garden. I have several 7’x7’ pop up poly greenhouses, several brown galvanized raised beds. I had decided to put these greenhouses up against the house to absorb heat from the house at night and be blocked from the wind, with buckets of water and pavers inside for the thermal mass effect that you have mentioned. I also have thick black plastic on the ground and I was going to either put pavers down or stack them but I was wondering if your pavers where also painted black wouldn’t they absorb more heat and stay hotter longer? And I was wondering if my brown metal beds wouldn’t also retain heat being a dark color and metal, keeping my soil and roots warmer? I love these little pop up greenhouses because I will be able to flip them off the beds in the spring and replace them the following fall. Or that’s the plan anyway. Does it seem feasible?

[@GardenerScott]

Darker colors will absorb more heat. Because they absorb more heat they will stay warm longer. Pop up covers can be very effective at extending the growing season.

[@amyberchtold2728]

Excellent video, as usual. This was perfect for me as we bought a greenhouse last spring and it just sat there because the people that bought it did not research how to keep it going without heat....now I know what to tell them. I wonder if the plants need to be in ground vs in pots though. Thank you!

[@jerrydeanswanson79]

Thanks for the video. Appreciated. Been using many of your ideas in my 12x16 Cattle Panel greenhouse design. Am about 4 weeks into the job. At the point of putting up the plastic...when Wisconsin threw a few inches of snow at me...smiles. Anyway...supposed to be in the 60's next week. Work is coming along well. I plan to post work-in-progress photos on my business website when I am done. I will give you a link when it's done. And the way I like to build things...there has not been a lot of cost/benefit analysis going on here...smiles. I'm a Master Gardener, 73, and always wanted a greenhouse. Bout time, eh? About heating...I like the passive methods you used. Might do the gravel and paver thing. I don't know if I want to give up the space the barrels take. Question is...for those days when the passive can't carry the heating load...what do you do? I have seen some growers who recommend the Mr. Heater tank-top propane heaters to supplement their greenhouse heat. Jeez...on Amazon they are only $35. Hard to beat that price and I have relied on Mr. Heater equipment in the past with no issues. Anyway...that's my Plan A.

[@GardenerScott]

I don't' have supplemental heat in the greenhouse so on days when the passive heat can't carry the load, it gets cold in the greenhouse. After a season of documenting the temperature changes without heat, next year I'll experiment with easy heating. Something like Mr. Heater may be on the agenda.

[@jerrydeanswanson79]

One of my goals is to have a better permanent home for my 41-year old Hibiscus tree. It has had a flat-top for many years, as I needed to limit its height, so I could drag it through the patio door twice a year...smiles. And we have a couple nice Figs that would also approve of a better environment. @@GardenerScott

[@Leekle2ManE]

This reminds me of an episode of a british show called A Year at Kew. In the episode, the worker in charge of the Tropicals house lost several plants on a rather cold night. She couldn't quite figure out what had gone wrong. The culprit? She had drained the large pond located in that room. Without the pond to retain heat, the room got too cold for the tropicals. I don't think she returned for season 2 of the show.

[@GardenerScott]

That's a hard lesson to learn and a great job to lose.

[@HeatherDuffy1313]

Tarping at night over the 4 day cold stretch would've helped. Even tho tarping's terrible with no snow, lol. I'm going to run out of indoor space before last frost. Thank you for the outline and showing results! ❤

[@GardenerScott]

I wanted to see what would happen with no other protection. Next year I can use extra cover to help.

[@HeatherDuffy1313]

It's still pretty good! And I'm surprised your pepper plants did so well at 27°!

[@441rider]

I have a small greenhouse with tubs of water and for summer run duct tube 3" into te tub to transfer summer heat from roof area into it. When it freezes in Canada keeping the water from icing is trick. May need car diesel heater or solar 12v powered 100w heater for 4 weeks on 2-3 sealed 100ah batts..

[@StaceyG-l6m]

Good job anyway the freezing weather goes 🙏✅✌️❤️

[@jamessever8936]

You should try painting the table black too@

[@StaceyG-l6m]

Black is Back!✅❤️✌️🙏🌍🌈😎🥸🦋🫶

[@jazz-as-taff3427]

Thank you, scot, for a great video. Very informative a d gqve me many ideas growing in winter

[@zakkrueck2362]

i would love to see more videos about your greenhouse over the winter GS. i too have a Sungrow, which i am still modifying and tinkering with in order to make it warmer over the winter, like by building cold frames inside.

[@GardenerScott]

I am planning on at least one GH video during the winter, maybe more.

[@mikebertrand5769]

Great video, Scott! Have you ever thought about putting a little solar panel with a battery that would charge a battery and either use little heat mats or even a couple lights just for the coldest day.

[@GardenerScott]

Yes, I am planning on adding solar panels and batteries too. I want to follow a gradual implementation. Last winter I monitored the greenhouse with no passive heating. This year I have the water. Next year I'll add a heat source.

[@petrusvandermerwe-ln7vs]

nice vid glad i discovered yor channel thz

[@maggiemomo9259]

This is great info..

[@jamessever8936]

Did y'all see the doggie in the back?!?! LOL

[@lindaferguson593]

Have you thought about doing a vestibule entry to keep most cold air from entering into greenhouse when you go inside it?

[@GardenerScott]

Cold air seeps through other areas throughout the night and the polycarbonate panels gradually cool it as well.

[@lindaferguson593]

@GardenerScott ok....

[@davidpopoola3805]

Thanks so much for the incredible video. This has taught me so much. Thoughts on the best materials to use for the water containers? Would thicker, more opaque plastic be better or worse for keeping the greenhouse warm do you think?

[@GardenerScott]

My plastic containers are thick and opaque and work well. Both metal and plastic will work. A study by Small Farm Magazine showed no advantage to using either so whichever you have access to is a good option.

[@shaunnichols8170]

I wonder if using a propane heater would help for the more challenging days of charging those batteries.

[@GardenerScott]

Great idea. I recently filled my propane tank with the thought that I'd try that this year.

[@kirkchurchil8216]

Have you thought about getting a small “Mr. Heater”? I’m going to get one for my hoop house I’m building right now and plan on using it for emergency situations when it’s super cold. You can hook up a thermostat to them so it will only turn on when you really need it. If you use propane the only gases emitted are co2 and water by what I’ve read so the plants can use all the by products from the system.

[@GardenerScott]

I'm considering propane because I don't have electricity. Thanks for the suggestion.

[@kirkchurchil8216]

@@GardenerScott yeah I installed one in my garage, no electricity needed works great. Video was good by the way 👍👍👍

[@dragonchild36]

Hi, Gardener Scott! Sophie here in Austin. I've been enjoying your videos for a few years now. Thank you for making them. Here in TX, I often have to open my GH for airflow. Could you please tell me how you deal with your GH air circulation during winter when it's so cold? Thanks.

[@GardenerScott]

Hi, Sophie. I monitor the thermometer in my greenhouse and open the door or window when the temperature rises during sunny days. I'll keep it closed when it's cold and cloudy. Because I just have a few plants growing in it, air circulation is not as important as when the greenhouse is filled with plants during warmer months.

[@zakkrueck2362]

better to leave the snow on top or take it off? i bought a floor squeegee to get mine off.

[@GardenerScott]

The snow helps hold the temperature a bit more stable at night, but removing it during the day lets more sun in to warm it up.

[@frstchan]

I live in south Sweden and we have surprisingly mild winters however we have very little sunlight. So heating from the sun wont help.

[@GardenerScott]

The sun is needed for the water to be most effective.

[@bevbarry9637]

We don't get those kinds of temperatures here in Melbourne, Australia. I am still trying to get over you standing there in those temperatures with no gloves or jacket! I am also struggling with temperature in my greenhouse, it is too hot during the day and needs opening up to get below 30C and then it needs to be closed up at just the right time to keep a bit of warmth in there so my seeds and seedlings don't suffer. Big learning curve going on for me this year.

[@GardenerScott]

After many years of cold exposure and my dry humidity it's not difficult to spend a brief period outside when it's that cold.

[@bevbarry9637]

It's amazing how the human body can acclimate to different environments and from my own experience I know that it only takes going through a season once or twice for it to become the new normal.

[@johnjude2685]

If weather drops can you quickly drain the barrels or you have antifreeze to prevent busting from expanding?

[@GardenerScott]

The water mass shouldn't freeze even in severe cold as long as I can get regular sun, but I'll keep monitoring it.

[@stephengerth1189]

Got the same type of greenhouse, but in northern Sweden (lat 64). Got 1 rain barrel/ reservoir 200 liters grow lettuce and some Swiss chard into the end of November. When the cold sets in do you empty the barrels?

[@GardenerScott]

No, I keep the water in the barrels to help warm the greenhouse.

[@BoothbyGardens]

I won't be growing anything in my greenhouse over winter, but I do have a large garbage bin that I'll be filling with water to gauge how that will impact the greenhouse temps over winter to determine if 2025 will be feasible for winter growing. For now, I've got my tomatoes and cucumbers going in my grow tent indoors.

[@rebeccakrebel7413]

What directional side of the greenhouse are your barrels on?

[@GardenerScott]

They are on the back side. For me, that is north. The sun shines on the front.

[@SunnyNot]

What are those green planters in the back? (with yellow fruit tree) They look really handy

[@GardenerScott]

They are Oasis boxes from the UK. I wasn't impressed by them.

[@zakkrueck2362]

my greenhouse is also 18" underground.

[@felixyusupov7299]

Maybe your should install a mini wood burner. As long as you are using external air for combustion it will only add heat to the small space.

[@GardenerScott]

My next experiment will include simple heating like that.

[@alicias9928]

Do you have a video about what all that water does in the summer? Do you take it out?

[@GardenerScott]

The water stays in the greenhouse all year. It absorbs heat and helps moderate the temperature in summer. Here's my summer greenhouse video: kzbin.info/www/bejne/nXW1m5eXe9Ciqas

[@hanhbui9329]

Love the video with all the helpful information. @GardenerScott, I am just curious, when I have a few days without much sun, would it help if I fill up the jugs with hot water (I can boil them inside and pour it into jugs)? Thank you.

[@GardenerScott]

Jugs with hot water will release that heat to the air. It might make a difference if the sun can't do the warming.

[@hanhbui9329]

@@GardenerScott Thank you. I will try that. I have a big dragon fruit plant and a fig plant in a flimsy tent "greenhouse". Before I bring them inside in November, I just want to see if they can stay outside for the rest of the month when the temperature during the day is still good but is in the 40s at night (zone 5b).

[@hanhbui9329]

Also, does it help if the containers are aluminum or not plastic? I can put the whole pot of hot water (covered) in there instead of pouring hot water into jugs?

[@GardenerScott]

The aluminum will transfer heat faster. Both absorbing and releasing.

[@hanhbui9329]

@@GardenerScott Thanks. I will have to look for old aluminum pots :-).

[@alanmcrae8594]

Great experiment and the viewer comments contain a lot of additional real world information as well. Can you tell us what weather station system/model you are using? (I see it monitors both outside & inside conditions, plus it monitors UV radiation, etc.) NOTE: just found your (Video #410) Ambient Weather Weather Station. Seems like the key to winter greenhouse growing is going to be monitoring environmental conditions as accurately as possible and having a greenhouse environmental control system that combines both passive & active systems to keep conditions within acceptable ranges on the least amount of electricity possible. This should be doable with modern technologies and result in four season food harvests in almost any climate zone. A full featured weather station is a great start to monitoring conditions, so it would be helpful to hear your assessment of the system you are using. (Also, does it log historical data so you can look back and analyze control system performance under different weather conditions?)

[@GardenerScott]

I have a newer system that I show in this video: kzbin.info/www/bejne/ZoWTnWhnaZWlfsU It's a Tempest system. Tempest Weather Station shop.tempest.earth/?ref=gardenerscott Use code "GARDENERSCOTT" for 10% off It logs historical data and gives accurate forecasts.

[@janetc3707]

Do you ever have to change the water in the barrels? Does it become stagnant?

[@GardenerScott]

They are sealed. The water may become stagnant if the barrels aren't clean to start, but that is not a problem as a heat source.

[@ferq86]

How about putting a heat generating resistance in the water to overcome freezing days without sun?

[@GardenerScott]

That is an option.

[@suel1634]

Great topic. I've been thinking about building a greenhouse, and using passive heating is one of the options I was looking at. I've also been looking into subterranean ones where half the greenhouse is below ground with a sharp angle roof that allows passive heating in the cooler months and shades the water barrels in the hotter months. Do you have any experience with this?

[@GardenerScott]

I have a gardener friend with a walipini greenhouse. He has more stable and moderate temperatures with that kind of buried greenhouse. He doesn't use water barrels but it does retain some heat until the severe cold temperatures set in in.

[@Maria-In-Motion]

Love your videos. How many barrels do you have in the GH and how many gallons are they each? I’m looking into the Planta Sungrow Urban for my backyard. I need it to be 100% off grid. Do you do rain catchment? If so, do you have a gutter system on your Planta?

[@GardenerScott]

I have three 55-gallon barrels, along with a couple 34-gallon bins and many 1-gallon jugs for a total near 250 gallons. I don't have a gutter system but I have wood chip mulch all around the greenhouse so the soil outside is moist from any runoff.

[@Austin1990]

Engineer here. The actual number of gallons may not matter as much as the area of sunlight that warms them. That area determines how much energy the water is charged with. The amount of water will determine the temperature of the water after absorbing all that sun energy. The warmer the water, the more it will heat the greenhouse, but how long before the water cools off will ultimately be restricted by how much sun energy it soaked up.

[@soniamarshall9293]

Would it be better if the barrels have no table over the barrels also would like to know if the barrels have its cover on?

[@GardenerScott]

It might be better without the table but I needed the space for working and growing plants. The barrels do have covers.

[@craigdawson7632]

What are your thoughts on underfloor air geothermal with a soak pit for drainage and cold air soak. What are your spec's there? Average rainfall Min Max temps Average sunlight hours 🤤took min a min to realize you were talking in F not C 🤣 I was listening while doing other stuff. 16C is a good outdoor temp for summer. Data logging is under rated.

[@GardenerScott]

Geothermal heating can be very effective for greenhouses. The biggest limitation is the initial cost and construction. My annual precipitation is about 16 inches. The temps range from -15F to 100F. We get about 350 hours of sun in July and 220 in November.

[@brandyburgess8267]

is it true to add aquarium heater to water barrels to heat up the greenhouse?

[@GardenerScott]

You can do that, but a regular air heater might be more efficient.

[@brandyburgess8267]

@@GardenerScott thanks

[@ginaortega3901]

Could I use clear milk jugs filled with water or do I need black?

[@GardenerScott]

Clear works fine. The black just increases heat absorption a bit.

[@gjsmimi4474]

Gardener Scott, is your greenhouse double layered?

[@GardenerScott]

It is a double-layer polycarbonate.

[@stephenhope7319]

Gardener Scott, what is the name of the plant to your immediate left in the beginning of this video? I had one come up in one of my planters this year and do not remember planting it. It grew 3 feet this season so I am ready to leave it in the planter and see what happens. Looks like a fig but unsure. Thanks . ( btw, Sacramento, zone 9b, can it be left outdoors over my winter?)

[@naurekk]

I think you are right about it being a fig, Picture This (plant ID) app says it is a fig as well

[@stephenhope7319]

Thanks for that info. I was kind of surprised that it grew 36 inches tall in one season. @@naurekk

[@GardenerScott]

The plants to my immediate left are pepper plants. Just behind me to the left is a Chicago fig.

[@catejordan7244]

Curious, does it get too hot in the summer? Is the venting enough to keep it cool enough to grow in during the heat of the summer?

[@GardenerScott]

It can easily get too hot. Venting is important and other methods may be needed. Here's how I did it this year: kzbin.info/www/bejne/nXW1m5eXe9Ciqas

[@monicam.8006]

May I proffer an April 1st video for you, please. Take some of the B.S. gardening stints on the internet today, and re-create them.

[@GardenerScott]

Thanks for the suggestion. I have some videos like that where I dispel myths. I'll start thinking about the April Fool's aspect.

[@danielanac5093]

with a sistem (like an solar cooker with mirror to heat more the water) it will work?

[@GardenerScott]

Solar cookers can generate focused heat. As long as there is a system for storing that heat it can work.

[@stringstriker3418]

Could you add some boiling water to your water barrels?

[@GardenerScott]

My barrels are sealed and covered so it isn't an option for me now.

[@michaelgusovsky]

good info, thank you. but, don't you think your greenhouse would resist cold better if you had used wood framing instead of aluminum? aluminum is a conductor of heat.

[@GardenerScott]

It was a kit and the metal framing gives it the strength I need for my weather. A wood frame does make a difference in greenhouse design and the temperature variation.

[@michaelgusovsky]

@@GardenerScott makes sense.

[@markthurst9751]

Is a heat lamp a good way to supplement heat in a greenhouse? I was considering that or some way to heat my water tank.

[@GardenerScott]

It can provide good heat as long as it doesn't pose any risk of fire.

[@Trinithies]

I live in the NE and my platform of the greenhouse is pressure treated What should I add to platform to keep the heat inside of the greenhouse?

[@GardenerScott]

Consider cement backer boards and/or concrete pavers.

[@themeindertsmas5502]

Do you need to change or condition the water in the barrels, so they don't get rank? Would it help to dye the water black?

[@GardenerScott]

Adding chlorine bleach when filling can help. The containers are sealed and filled with clean water so there is little likelihood of rankness. Dying the water isn't necessary.