I am growing some plants indoors under LED lights. I've noticed with some of the plants, like tomato, pumpkin and broccoli, that they just lay on the ground. Is there any kind of support that is necessary for them? I believe tomatoes need some, and I have a few rods I purchased they can climb up. But the way my setup is, it is a rack, and the tomatoes, for example, only have 15 inches vertically to grow. The rods would not fit in the containers, unless I take them off of the shelf.