wxcrawler

I cannot help you with a definitive answer. However, i can say that I made my own planter soil and it is the best I have. I recall buying a large bag of perlite and adding it in over time. However, I also used coco coir and mixed it in with my clay along with that perlite. After one season (bugs working the soil) I had some very good soil. It's my shallow hugelkulture plot. Everything thrived in it until last fall. Nutes are depleted, I think.
Oddly, I no longer see the perlite! That was one of the few times I put money into the garden. I do not know if it was the coir or the perlite that helped the most. I tend to think it was the coarse coco coir.

Heh. with bare clay, almost any amendment will be an improvement. I'd say add your mix, but also mix in a lot of compost and organic material - composted manure, leaves, grass clippings, sawdust or wood chips. Once you've added the compost et al, wait a couple of weeks and then add a couple of inches of coarse-grained sand, such as builder's sand. Perlite will work, too.

Get a soil test (county extension agent). That'll tell you what else needs to be added.

Don't expect instant results. It'll take a couple or three years to get the soil where you want it to be.

I would get your hands on some woodchips. Also check out the soil forum for interbay mulch / lasagna gardening / composting in place. I have built a raised bed with a wood chip base and I was pleased with the results. However it shrinks :) so take that into account.

Do you have access to coffee grounds? Stsrbucks gives them away if you don't.

Lee, It will work just fine. I add old container mix to my clay soil all the time. The key is to mix them together well. Because you are building those raised beds, your plant roots will be fine even in periods of heavy rainfall. You're doing it the right way.

What would be the wrong way? To dig out and remove all the clay and replace it with the container mix dumped into that excavated hole without blending any clay with it. If a person does that, they have essentially created a grade-level pond/bathtub filled with a growing mix, and that pond/bathtub will hold water forever because of the surrounding clay.

Raised beds are almost always better for gardeners in our state than grade level ones, precisely because they allow heavy rainfall to drain away. (If I were in extreme western OK, I might choose to go with sunken beds or waffle beds than raised beds but they have different issues in western OK than the rest of us do since their rainfall is so much lower.) Raised beds allow that excess moisture to drain away even when the clay beneath them drains more slowly than the raised beds.

Amending clay to improve drainage is a never-ending job. Being able to recycle old soil-less mix into the raised beds is a terrific way to continually improve your soil. I add every kind of organic matter I can get my hands on to my soil and it has improved so much over the 15 years we've been here that people have a hard time believing the brown loamy soil in our garden once was dense red clay.

Dawn

I read this earlier and was going to post a picture but hated to show all my junk, I always have some kind of project going on and my place is always junky.

I live in a low area and have a terrible drainage problem. Look at the holes that have had water in them for months, but yet my garden is dry enough to till. The only difference in my wet lawn a my workable garden is organic matter. Enough organic matter will cure most gardening problems. You can see some of my hay and shaving in the background, I am out of leaves.

You have heard that the three most important things in a business are Location, Location, Location. I also believe the three most important things in a garden are Organic matter, organic matter, organic matter.

Larry

Thanks for the replies, everyone. I started dumping my old mix today. My old (full) containers have been sitting in my backyard since last year, where they never get sun during the winter. I was shocked when I dumped some of them out and the cores were still frozen solid. I guess that's a testament to how cold this winter has been.

Lee