Cool, looking forward to seeing the patch as it grows. I'm thinking they should be thick enough that they will shade out the grass. I planted a 250 yard strip (approx 12 foot wide) of cow peas years ago and man they did great. By late summer they were up waist high. Deer kept using them all the way up until I mowed them down for a fall food plot. If you think about it, set up an exclusion cage. I used to make them out of 1/2 hardware cloth and some rebar. I drove in four pieces of rebar or fence post and wrapped the hardware cloth around it to exclude a small section from the deer grazing. This let me know how much the plot was being grazed by the deer compared to the excluded area that they could not reach. It is surprising seeing the difference.