The magic of mulch

Joe Lamp'l
Scripps Howard News Service

I'm fond of saying that there are three things you can do to eliminate 95 percent of your gardening challenges. First, put the right plant in the right place. Second, improve the soil by adding plenty of compost and organic matter. Third, add mulch.

Of all the ways I can suggest to save time and work in our landscapes and gardens, the generous use of mulch is a key component for allowing that to happen. Here are some of the main ways mulch gives back so much.

Weed suppression

One of the most loathed tasks for any gardener or weekend warrior is weeding. Although mulch won't guarantee a weed-free landscape, it does greatly suppress seed germination by blocking sunlight to the soil surface-- an important ingredient many weed seeds need to germinate. Unfortunately, weeds are weeds, partly because of their ability to sprout and grow in the most challenging conditions. Birds, wind, pets and people will always be couriers of weed seeds, so they'll still sprout in your mulch. But when they do, they're easier to pull out since much of their roots are in the loose top layer of mulch.

Moisture retention

You don't need to be a horticulturist to know just how quickly exposed soil surfaces can dry out under the hot sun. Over time, moisture below the surface evaporates away. Unfortunately, many roots suffer from the dehydrating effects of exposed surfaces. A 3-inch or so layer of mulch acts to provide a protective, insulating barrier from the evaporative effects of the sun and heat, holding in precious moisture far longer and deeper than exposed surfaces.

Moderates soil temperatures

Similarly, that same layer of mulch moderates soil temperatures by helping to keep temperatures below grade cooler in summer and warmer in winter. Think of mulch as a thermal insulating blanket. Having a generous layer of mulch around plants and trees can literally make the difference between life and death when it comes to extreme temperatures in summer and winter.

Reduces plant disease

Many disease pathogens reside in soil and can easily be splashed up onto plant foliage, which can then become infected. Mulch reduces the chance of this happening by providing a protective layer, blocking the splashing of pathogens onto stems and leaves.

Improves soil

As opposed to rubber mulch, any natural mulch will break down and decompose in a relatively timely manner. As it does, it improves the existing soil with important organic matter, a vital ingredient to sustaining soil quality and nutrients.

Buyer Beware

Unfortunately, decomposing mulch can also add material you would never want in your soil. This includes substances, such as arsenic, from pressure-treated wood. Play it safe with the mulch or soil you buy and look for the certification seal from The Mulch and Soil Council on approved bags. It ensures that the product you are buying is free of unacceptable chemical materials.

I almost learned about contaminated mulch the hard way when I nearly purchased a load containing old pressure-treated wood. As an eco-friendly gardener and a father, I never would have knowingly made such a purchase. I believe so strongly in sharing this message that I became a compensated spokesman for the Mulch and Soil Council in 2007.

Aesthetically pleasing

Finally, there is no denying the eye-pleasing appeal that mulch adds to any landscaped bed. On top of the valuable benefits mulch offers to the health of plants, a generous layer of mulch adds the finishing touch that complements and sets off your landscape or garden beautifully.

So the next time you're looking for simple ways to dress up your landscape and reduce the amount of work needed to keep it looking great, put the right plant in the right place, improve the soil and add mulch.