A good layer of natural mulch will save gardeners work

There are three things you can do to eliminate 95 percent of your gardening challenge — put the right plant in the right place; improve the soil by adding plenty of compost and organic matter; and add mulch.

The generous use of mulch is a key component to saving time and work.

Here are some of the main ways mulch gives back so much.

Weed suppression: Although mulch won't guarantee a weed-free landscape, it does greatly suppress seed germination by blocking sunlight to the soil surface. Unfortunately, weeds are weeds, partly because of their ability to sprout and grow in the most challenging conditions. 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.

Moderates soil temperatures: Similarly, that same layer of mulch moderates soil temperatures by helping to keep temperatures 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.

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: 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.

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.

Joe Lamp'l, host of "GardenSMART" on PBS, is a master gardener and author.