cover crop for help hard clay soil
Does anyone out there know which cover crops are best for breaking up hard clay down deep? I think I read somewhere about some type of grass or grain whose roots could penetrate a couple feet through hard soil.
I have a small fenced area in which I am planting several 4x8 raised beds. The soil is all fill dirt that was excavated from a neighbor's building site and dumped behind our house. We live on the side of a small mountain in western NC and the land behind our house dropped off so steeply that it was very difficult even to climb down. When the property owners adjacent to us decided to build their huge log home, he needed to get rid of allot of dirt, so they asked us if they could dump it behind our house. NINETY truck loads later, we have a respectable back yard, and I have a spot for a garden.
The bad news is the fill dirt is all clay with lots of rocks. For my first four raised beds I dug down about 16 inches. I replaced the dirt with composted manure, peat moss, vermiculite and a little of the clay minus the rocks. I built a frame for the bed using 2x4s so when I filled it to the top I had about 20 inches of excellent soil. Things are growing great, but that was a LOT of work and buying the vermiculite and peat moss got expensive.
For the next beds, I'm wanting easier. I'm thinking of not digging at all - just laying the 2x4 frame right on top of the ground and filling it with my soil mixture kinda' Square Foot Garden like. Let earth worms and nitrogen fixing cover crops do all the hard, deep work. I know I won't have the same good results right away, but, dang, I'm tired of digging.
Anyone out there have any nitrogen-fixing wisdom for me?