News / Life / Clark County Life

Gardening With Allen: Apply mulch to improve soil

By Allen Wilson

Published: April 8, 2023, 6:00am

Applying mulch or bark dust helps build up the organic matter in your soil, making heavy clay soil less dense. (Allen Wilson)

I have a heavy clay soil. What is the best way to improve it so my plants will grow better?

The most important thing I have ever learned about gardening is this: The key to improving plant growth with clay soil or any other soil is to continue to add organic matter on a regular basis.

It sounds like you are in a hurry to improve your soil. So you need to bring in some extra organic matter. The cheapest and best source of organic matter in our area is the finely chopped up bark from lumber trees that we refer to as bark dust.

Apply 2 to 3 yards of bark dust over 1000 square feet of soil and rototill it into your soil 8 inches deep and you will get an immediate large improvement. That will cost you about $100 to $150 per 1,000 square feet if you pick it and till it yourself. It will cost more if you have it delivered or hire someone else to do the job.

If you hire someone to landscape your home, the first thing they will want to do is apply several inches of topsoil over your clay soil before planting. Instead, specify that they till in 2 to 3 inches of bark dust. You will end up with better soil than the topsoil.

When I was a new young homeowner with more time but less money, I picked up free organic matter that my neighbors were discarding. I asked for all their grass clippings and raked up their leaves in the fall. These were piled on my unlandscaped soil and tilled in just like the bark dust, with similar immediate improvement.

The owner of the apartment complex where we now live allowed us to plant flowers on two sides of a large corner apartment. There is a large mature cedar tree on one side which continually drops needles around our flowers. When the landscape maintenance contractor started raking up those needles, I immediately stopped him.

“Don’t take my mulch,” I said.

When my wife said, “It will look better if they remove it,” I said, “No, leave it. We will cover it with bark dust.”

Many gardeners and landscapers apply an inch or more of bark dust yearly as a mulch around trees, shrubs and flowers. That alone will prevent 90 percent of weed growth by shading the weed seeds. If you want 100 percent, apply a weed barrier fabric first.

Make use of all your natural organic matter such as lawn clippings and leaves. If you don’t like their appearance as a mulch, compost them in the corner of the back yard until they turn a nice dark color or cover them with bark dust.

Allen Wilson is a Vancouver gardening specialist. allenw98663@yahoo.com

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