Compost can be used in many ways to improve the clay soils in Kansas. It takes time and several applications of compost to turn the clay into a lush, growing media.

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Composting - Where to Use It

So you’ve built your backyard compost bin and you’ve had success. You’ve turned your leaves and food scraps into that black gold that’s just wonderful for our Kansas soils. Now the questions is, “what do you do with it after you have it?” Compost is the best thing you can add to our native Kansas soils to help break up that heavy clay structure that we have.

Clay soils tend to have negative factors. They tend to be very wet when it rains in Kansas, and then when it dries, you can carve them into bricks and build a house. The best use of the compost is to work it directly into the soil to help improve that structure. Keep in mind that the roots grow six to eight inches, or more, so you’ll want to spade the compost into that depth to get a nice, deep root zone.

You can add compost in the fall to our vegetable gardens. That’s the ideal time because as you’re preparing in the fall, you can course spade to work the compost in, and let it break down over the winter. Then in March or April, you’re ready to plant your vegetables.

And in the annual flower garden, you can follow the same procedure. As the frosted annuals come out, you can spade the soil, add the compost, and then you’ll be ready for next spring.

When you’re working compost into the soil, you’ll probably need to add a minimum of one to four inches. That’s a fairly wide range, but the more that you can put in, the better it becomes.

Remember, it takes time. Don’t think that you’re going to see the soil transform in one year because our clay particles are so tough to break down. It may take several years of continually adding compost to get that rich, loamy soil that we see in garden magazines and books.

Another use for compost is to use it as a topdress. A lot of people will buy mulch in the spring to put around their flowers, trees and shrubs. A one to three inch layer of compost around those plant materials can help control moisture, cool the soil, and keep weeds down. It eventually works it way into the soil, to help improve it.

Compost can also be used in our lawns. It can be broadcast over the surface in a very light layer – one eighth to one fourth of an inch at the most. You don’t want to cover the grass. You just want it to filter down into the soil surface and help break down thatch. The best time to add the compost to the soil is when you time it with core aeration. So, for a cool season lawn such as bluegrass and tall fescue, you would probably do that in the fall during September or October.

For those of us that grow warm season grasses such as Zoysia or Bermuda, the lawns are core aerated usually in late May or early June. That would be the best time. Just pull the plugs out, and the compost filters into the holes and helps to break up the soil.

So as you can see, there are a lot of uses for compost. You probably won’t generate enough compost in your backyard that you’re going to say “Wow, I have excess!” because there are so may uses from the vegetable garden, the flower garden, mulching trees and shrubs, or in your lawn.

As I said earlier, compost is black gold. It helps take those Kansas clay soils and turns it into a lush, growing media that we dream about.

This feature story prepared with Dennis Patton, Kansas State University Research and Extension Horticulture Agent, Johnson County. For more information, visit your local county extension office or visit our website at

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