Walls of water, grasses & raspberries

Last year I started my tomato plants in walls of water. The walls did protect my plants from cold temperatures, so that I had earlier tomatoes than usual. But one of the walls fell over. By the time I noticed, part of the tomato plant had been smashed under the wall. The plant recovered but never grew as big as the others. Have you ever heard of this happening? Yes, occasionally. It happened to me once, when I first was using walls of water but never again. Let me pass on a few tricks for keeping the walls upright: Before setting a wall in place, level the ground. Be scrupulous about the circl...