Since you tilled the leaves in, you'll need to add some form of nitrogen to help them decompose since they're high carbon.

As a general rule, you probably want to avoid tilling clay when it's wet. If it's damp, that's okay, but it can be a problem when it's wet. Lumps of clay are okay and probably desirable. If you break up the lumps too much, you'll end up having it pulverized.

The peat moss has no nutrients in it, and the soil bacteria do not like it anyway so they won't digest it. The leaves will have a lot of nutrients, so whether you would need to add anything, other than compost, will depend on what a good, reliable soil test might show, and how active the Soil Food Web might be there.
Not too far inland from Lake Michigan around Chicago the soil is clay, along the beach front it is sand but it quickly becomes clay just a short distance from Michigan Avenue.

Thanks for the replies... I'm actually about 60 miles outside Chicago but still a lot of clay, at least in the area I'm in. I'll bag some grass when I mow again this week and mix that in with the leaves.

I did deal with the clay problem at my last house here and had a lot of trouble growing some plants but I didn't start with both leaves and grass and didn't till in nearly as many leaves as I did here. I put the peat in just to mix things up and it was suggested I use that from a local nursery. I know there are no nutrients in peat and the little I used probably won't do a lot anyway as far as holding moisture.

Brian

I've got clay and I'm doing lasagna beds to make flower beds. The first year it helps, the second year (this year) the soil looks really really good. I've also been mulching the beds with leaves every fall.

yeah, i'll have to say, lasagna bedding is one of the coolest things i've witnessed in the garden, it's amazing how much progress my once lifeless soil changed over the past year.

I would try spreading some coffee grounds in the soil, but not too much. I'm finding that it modifies the structure of clay.

Any links to creating a lasagna bed? I've never done it and never heard of it until I came here.

Brian

Since you have put the leaves in and their breakdown will rob the soil of some of its nitrogen, you have two choices. Wait to plant and let the soil food web break them down over time and the soil will be better prepared later. Or you can offset the loss by adding nitrogen (the grass clippings are one good source). As kimmsr stated, you will not know how much nitrogen (or anything else) unless you get a soil test. Without one you will be guessing, but that works for some people too.

I usually try to add my leaves in the fall to beds that I will not be using over the winter. There is plenty of time for them to break down over the off season. They are a great addition though (to the soil or the compost).

Steve

Hey Brian -

Here are a couple of links to get you started.

Lasagna Gardening 101

Lasagna Gardening

Val

Thanks all, I'll look into finding a soil tester, I had one at my old place but that was years ago. I'd like to test ph as well, especially for a spot I want to put some Hydrangea.

I just moved here last July and didn't have time to sort this bed out then. 3 sides of the house including this one were covered in river stones and it was a major chore removing what I was able to last fall. Hopefully I'll get the other areas cleaned up, the west side of my house is bare and needs a lot of work, but I want to get leaves and grass mixed on that side as well as the front before winter.

I also know clay is good but too much is bad, turns to concrete and that's why I mixed in some peat but more so the leaves. As I said in my OP there was landscape fabric covering the borders and nothing was ever able to get down into the soil/clay. Just another project of many I want to do around here but eventually things will look good.

Brian

Contact your counties office of the University of Illinois USDA Cooperative Extension Service about having that soil test done.
Anyplace that sells any product, ie. a nursery that sells peat moss, will tell you that you need that product and many of those places would sell you ground up glass if they thought they could convince you it was good for your soil.

Here is a link that might be useful: UI CES

Ground up glass, that would be great mixed with my compost then added to the beds! That would break down the clay clods! ;)

Steve

And it's oh so good on root veggies, sort of pre-chews it for you.

I have read that adding sand helps the drainage in clay soils.
Terry

Terry, if you add enough sand to clay it could, but Cornell will tell you that it takes 75 percent sand by volume (most others say 45 percent) if you are going to amend clay with sand and that much sand simply makes that process much too expensive.

Someone at our local Farm store told me that gypsum modifies clay. Anyone tried it?

Gypsum does not alter the structure of a clay soil, unless the area is sodic. The chemical reaction between the calcium sulfate and sodium chloride enables the clay particles to flocculate normally. That gypsum improves all clay soils is a myth that just won't die.

Dotty, I have used gypsum extensively in the coastal regions of S. Carolina, where salt water intrusion, occasional flooding, soil contamination from aerosol salt causes problems on golf courses, lawns, nurseries, and landscapes. Gypsum not only improves the texture of the soils, but allows the sodium to be leached.

The best amendment for a clay soil is organic matter. If the site is a wet location in the first place, fix it before amending.

Why not just buy a truckload of compost and till it in or if you're in no hurry just spread it on top.