Friendly Friday Thread

Where can I find information about actual soil composition/mixes?

I'm considering buying a piece of property which has some 5' wide by 4' deep by 22' long trenches with gravel bottoms. I have access to supplies of cheap sand and raw clay and can buy peat moss, top soil, worm castings, and composted manure at packagers' cost. I'm thinking this would be an ideal situation for mixing up some soil and using Jeavons biointensive gardening.

But I have no idea of what percentages of each thing to use!

I know all about soil pH and how to use a soil test kit, but most plant descriptions only say 'well-drained soil' or 'heavy soil' or other such things without stating what they mean by that. I guess I could make up some test batches, put them in buckets with holes in the bottom, pour on some water, and use a moisture meter to see how long they stay damp at different levels, but I still wouldn't know how those measurements would relate to descriptions. Does 'well-drained soil' mean it dries out in an hour, a day, a week . . .?

I've Googled every combination of keywords I can think of, and got no useful results. There are sites which tell what they think are the "ideal" proportions of different things for garden soil (and they vary widely), but none say which description they match or what plants do well in it.

Does anyone know of a useful guide that tells the proper soil mixture for different kinds of plants?

/r/gardening Thread