When I talk about my rocky plots, I don't think many understand what I mean. I'm not talking about some rocks mixed into the soil. All but one of my plots are along the spine of long narrow hog-back ridges. Those ridges exist because of the thick layers of chert preventing them from eroding away. And not chert gravel, but chert rock - often in layers about 4-inches thick. These plots CAN be tilled after some soaking rains (see first picture below). But once tilled, a couple of good rains will wash away what little powdery soil we have, leaving just the rock. The second picture below is literally the middle of one of my plots several rains after being tilled. That is why I have learned (thanks to Mega) to always keep something growing in the plots, and to keep a layer of mulch over the soil to prevent soil erosion and moisture loss. Let ground like in the second picture stand exposed in July and August and it will literally turn to concrete not even a pickaxe will penetrate.