I want to plant under the trampoline, but there's no way I can dig over in that space. The trampoline cannot be moved.
Although the grass is dead under there, the ground is no doubt still matted with roots. The topsoil is really thin, about a 6" layer on top of clay, stones, and builder's rubble. Hell to dig!
If I just break up the surface a bit and mulch with rotted manure, will the earthworms incorporate it like they do on beds?