Q: How deep do roots go into the ground for tomatoes and most
other vegetables in the home garden? I am thinking not very deep
and if so why do I need to waste time and gas tilling the entire
space? A: Depth is not the problem – it’s width. Roots grow
widely from the base of the stem of vegetables but they only
grow as deeply as they can find usable oxygen. Tilling increases
the area in which roots can expand. You should be mulching the
area between plants to prevent weeds.