Miles Flansburg wrote:Any plants that grow in your area that have deep roots will do the digging for you.
And not to scare you but some of the best things for this are "weeds". Look around your area for a place that has been scraped clear and see what weeds have come up. Those are the ones you want !
Mick Fisch wrote:
Plant deep rooted things. Stuff that will send a tiny little rootlet into the hardpan, then grow the rootlet thicker and shatter the hardpan. Then, once it dies, it rots in place and put organic matter in the hardpan.
Bountiful gardens offers a fodder radish (basically a daikon varient) that they say is good for breaking up hardpan. You grow it over the fall and winter, then leave the root to break down and add humus.
I haven't grown this plant and don't own shares in bountiful gardens, just naming a possibility that comes to mind.