Crystal

What you need to do is lay a really THICK layer of easily decomposed stuff onto the clay area and keep it moist. Plant some clay-tolerant cover crop and let the roots penetrate the soil to loosen it. When you cut the cover crop, the roots stay in the clay, decompose abnd create lots of tiny channels for aeration and drainage.

If the clay is not too hard, you can use oats (it's an annual). Sow them one to 1.5 months before your frost date. It will grow tall enough but not set seeds yet. Then the frost would kill them. Next year you can cut them down, mix in with the clay a little (some people say that such mixing is not even needed), and you can grow on them.

After a couple of years, you soil will improve greatly.

You can search the net for "green manure" or "green manure for clay soil."

Couple questions....

If I add gypsum can I do that and plant at the same time? Or do the gypsum and plants have to be time separated?

If I go with the oat solution, where do I get a very small amount of oat seeds?

As for clover, what is that? I only know the tiny three leafed kind that you occasionally find four-leafed ones in.

I have a bed in the back that has been dug up and amended but only to about a foot. It has mostly perennials growing in it and they're doing okay but not great. If I try to improve it through oats/clover/gypsum/etc. what would be the best way to go about that? I'm guessing I'd have to move the plants to pots for awhile or something? Clematis, black bugbane, tickseed, and goats beard is what's in there now; along with a few annuals.

Crystal

When I first started gardening here my DH tilled in sawdust, mushroom manure, cattle manure, and I planted a cover crop which was later tilled in. It was a blend that our local farm/feed store made up that was field peas, vetch, and annual rye. Our feed store sells various seeds in bulk so one can bag as little or much as needed. I also continued composting everything I could. The key is to keep adding organics continuously and over time the soil will improve. The good thing about clay is that it holds moisture and nutrients well so once you get it past that concrete stage it will be easier to work and your garden will do well.

We've always tilled organics in when starting a new bed as I think it's faster than just piling on the mulch. I know the worms can move thru the heavy unamended clay but one really can't plant in it and expect most plants to do well. My DH always goes over it at least twice to mix the soil/amendments as deep as possible. Then I expect the worms to aerate it deeper and I do everything I can to feed those little workers.

Before you pot up all your perennials you might try using alfalfa tea as a fertilizer/soil builder. I also bury kitchen scraps between my perennials which feeds the worms and in turn their castings feed my plants. Also if you mulch your perennial beds with a blend of grass clippings and mulched leaves it will really help as the worms love both of those and your plants will have the benefit of mulch.

I've never used gypsum as I don't think it's recommended for this type of clay. I also avoid sand. Lots of organic matter is the best for clay soil.

What does alfalfa tea do? How do you prepare it?

The alfalfa tea will help to feed the plants so they have a better chance of surviving while you are improving the soil with compost and mulch and by burying organics between the plants. I think it also makes the soil more habitable for the earthworms. Every perennial I dig up has many worms in the roots. While I don't know a lot about the life of earthworms I think they probably eat any roots that decay and perhaps also eat healthy roots. I expect the alfalfa tea helps to develop a healthy root system. Anyhow I know the worms don't hurt my plants and their castings are one of the best fertilizers so I like to encourage and feed them and the alfalfa tea feeds both plants and worms.

I know some people don't agree that alfalfa tea is very useful but I really like it and don't use a lot of other fertilizers. My plants seem to be healthy and I have few garden problems so something must be working! Alfalfa pellets can be purchased at your local farm and feed store and are quite inexpensive.

There are a lot of recipes for alfalfa tea which you'll find if you google. I don't follow those recipes as many recommend epsom salts which I'm not sure is necessary in my soil. If you know your soil is deficient in magnesium it would be helpful altho many recipes seem to use what I consider too much. Also I use the tea very diluted and more often than most recipes recommend.

To make the tea I put a few cups of alfalfa pellets in a 5 gallon bucket and fill bucket half full. Stir, or blast more water into the bucket with the hose every day. This aerates the tea. I just bail out about 1/2 quart and add it to water in my watering can. I keep adding water to the bucket until what's left looks very diluted then I use it full strength. The residue left in the bottom of the pail can be composted but I usually put it around the plants. Some people think the tea has to stink to be good but I prefer to aerate it sufficiently so it doesn't. Mine smells like alfalfa hay that's slightly fermented and not at all unpleasant. For some plants that are growing vigorously I water with diluted tea almost every time I water.