As the weather cools, it’s time to think about covering our gardens with mulch. The hard part is trying to figure out which kind of ground cover works best for your needs and the proper ways to use it! Gardening guru Ciscoe Morris offers a few tips about the different types of mulch:
Bark: Looks attractive and gives good weed control. If put down over an inch thick, or allowed to build up around plants, it can pack down and prevent air and moisture from reaching plant roots. Don't overdo it, and if it's already getting very thick, go out with a hook or similar tool and fluff it up. Bark is pretty much sterile and contains few microorganisms. Bark should never be mixed into the soil. As is true with any raw organic material, when it's mixed into the soil, the microorganisms in the soil use all the nutrition in the soil in the process of breaking the raw material down, resulting in a major nutrient deficiency.
Wood chips: This is what is left over after the arborist puts tree branches through the grinder. It's free, but can be hard to find. Call your local tree care company, or if you see someone working ask for the chips. Tell them how much you want and where to put them so you don't come home to a 30 yard pile in your driveway. Wood chips give good weed control. They don't pack down, so can be used without fear of blocking air and moisture. The chips bread down in one year and turn into beautiful topsoil. This also should only be used where you don't often move plants, because as is true with bark, if you mix the chips into the soil it will rob the soil of nutrients.
Leaves: Small ones can be raked right into the beds. Large leaves should be run over with the lawn mower, then raked or spread in the beds. The leaves attract gazillions of worms. They break down relatively slowly, and some people don't like the messy look, but using leaves as mulch does much to improve the soil. Don't mix the leaves into the soil, or again a nutrient deficiency will occur.
Compost: A very good mulch for use in mixed borders, perennial gardens and vegetable gardens, anywhere you tend to move plants often. Since compost is already broken down, it can be mixed into the soil whenever you plant, and it will actually improve the soil. It can be put 3 inches thick. Weeds grow in it, but are much easier to pull out since they tend to grow up in the compost layer. Compost is loaded with beneficial organisms that are good for your soil.
Manure: If the manure that you buy in the bag doesn't stink, it's been defanged, which means it's been composted. It isn't high in nutrients like fresh manure, but you also don't have to worry about it burning your plants. It's pretty much the same thing as compost.
Zoo Doo: My favorite mulch. It has some nutrition, and lots of other good microorganisms and minerals. Every year the Seattle Zoo has a lottery to sell this product. Use it the same way you would with compost.
When spreading mulch, remember it will kill evergreen ground covers and perennials if you cover them. Also never let it build up around tree or shrub trunks and stems. It can cause disease problems, and rodents get under the mulch and chew on the bark. Start at ground level by the trunk and increase the level as you move away from the trunk.
It's a good idea to mulch lawns with compost in spring and fall. Rake it out on the lawn, making sure to cover no more than 1/2 the height of the grass leaves. Mulching the lawn adds gazillions of beneficial organisms that help keep harmful fungi and other troublemakers from gaining an upper hand. This can be part of an over all lawn renovation, including aerating, and over seeding. If you overseed your lawn, only apply the compost about 1/4 inch thick.
Gardening with Ciscoe airs every Saturday morning on KING5. Visit www.ciscoe.com for more tips and ideas.