Magic of mulch evident in lack of weeds

posted May 14, 2018 7:47 a.m. (CDT)
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by / Bev Carney | Gardening Columnist

Recently a friend mentioned that she was not looking forward to weeding her garden. Much to my surprise, she had never tried using mulch.

Mulch does a spectacular job of suppressing weeds, and some types of mulch can even enhance the soil fertility and tilth. All mulches help keep the soil moisture consistent and keep the soil cool on those blistering hot days. In short, mulch is a miracle.

What sort of mulch should you use? There are many types from which to choose.

In the vegetable garden, you will have better luck with organic products which will break down over time. As they decompose, organic mulches help enrich the soil and your crops. You will be surprised at how quickly this decomposition takes place. A 5-inch layer of hay, applied in early June, will probably be reduced to a very thin layer come fall.

Hay is my all-time favorite product. I prefer alfalfa hay for its rich nutrient content but any old hay will do. We started using hay 28 years ago, and over the years our soil has dramatically changed from heavy clay to a lovely dark loam. Conventional wisdom says that hay will make your garden weedy, but we have never had that problem. When you plant, spread a light layer of hay and as the season progresses, be sure to top that up to a mulch of 4 or 5 inches. Straw also works well in the garden, but it doesn’t have the same nutrient content. These products can be pricey if your garden is large. You can get by using significantly less if you first lay down a layer of cardboard or several layers of newspaper over the ground. Topped with a couple of inches of hay, it is attractive and serves the purpose.

Shredded leaves make an excellent temporary mulch. They are rich in nutrients, attractive to look at and easy to spread. However they break down quickly and in my experience they make an ideal seedbed for many weed seeds that blow in on the winds. I find them ideal for the first layer of mulch around tiny seedlings.

Sawdust or wood shavings can also make a good mulch. When wet, these products can tend to compact and a thick layer can absorb the rains and moisture and keep the water from reaching plant roots, so don’t mulch too thickly. When friends empty their chicken coop, I gladly take their old bedding of sawdust mixed with manure and use it sparingly as a mulch.

For flower beds, trees and shrubs, many gardeners use wood chips. Sometimes you can find these free or quite cheap from tree trimming companies or your city services. Wood chips decompose slowly and can be an attractive mulch for more stable areas. I find they get in my way if used in an annual flower or vegetable bed. In seldom-disturbed areas such as a fence row, perennial bed or around the base of trees, they do their job very well. Keep wood chips away from the trunks of trees and the stalks of shrubs. Nestled right up to the bark, wood chips provide a safe place for chewing mice.

Landscape fabric is a popular option for a mulch product. It can be easy to use and somewhat effective. Don’t use it under organic mulches because you will lose the benefit of their nutrients as they decompose. The main problem with landscape fabric is that dirt gets on top of it and plant residue decomposes and soon you have a seed bed for weed seeds. To solve that problem, remove and replace the fabric every year or two.

Beverly Carney can be reached at

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