Dig It! Mulch Musings
by Sage & Snow Garden Club
September 28, 2008
Mulch is any material that covers the ground, keeps the ground moist, suppresses weeds, and/or reduces temperature fluctuations. The following are mulch types and their uses:
Loose mulches allow air and water through, so weeds that have roots can push through loose mulch. Organic loose mulches (grass clippings, leaves or compost) improve the soil as they decompose and attract earthworms.
Barrier mulches, such as cardboard or perforated plastic, suppress weed growth, including seedlings, and allow applied organic mulches to add organic matter to the soil. Barrier mulches need to be covered with loose mulch to keep them from degrading in the sun or blowing away.
Winterizing mulches are thick mulches applied to newly planted areas or to plants that may be susceptible to winter kill. These mulches include straw, leaves, and pine branches and are applied 6-12 inches thick after the ground freezes (or is close to freezing). In spring, draw mulch away from plants so the sun's warmth can penetrate the soil.
Cardboard makes a great weed barrier and allows moisture to get through. Put a layer of cardboard down and pile organic mulch on top or, for a fertility boost, pile manure over the cardboard. Next spring, poke holes through the crumbled layers and you are ready for your planting. This layering is called "lasagna gardening".
Lawn clippings build soil structure, moderate soil temperature, and conserve moisture. Allow the clippings to dry before applying and ensure there are no grass seeds. Apply a 1-4 inch layer that does not form a dense mat.
Chopped leaves suppress weeds, build soil structure, and reduce soil temperature. Be sure to tear, chop or compost leaves since whole leaves will mat and not allow moisture to penetrate. Use leaves as mulch in winter or spring in a 3-inch layer. Leaves in our area tend to make the soil slightly more alkaline.
Pine needles build soil structure, suppress weeds, and increase soil acidity (good for acid-loving plants). Apply a 2-4 inch layer around shrubs and trees.
Bark nuggetsconserve moisture and suppress weeds. Apply a 2-3 inch layer around shrubs and trees, preferably over rollout mulch.
Straw or hay builds soil structure, suppresses weeds, moderates soil temperature, and conserves moisture. Apply a 6-inch layer at planting time and as needed through the growing season. Straw usually contains fewer weed seeds than hay.
Newspaper suppresses weeds and conserves moisture. Use it in pathways between beds or rows. Cover with a thin layer of more attractive mulch and turn under when partially decomposed.
Plastic weed barriers are reusable, suppress weeds and conserve moisture. Use under other mulches. Black plastic sheeting warms the soil (so you can plant earlier) and suppresses weeds. The light reflective patterns that accompany red plastic mulch benefit tomatoes and some other crops and deter nematodes. Lay down plastic and anchor with rocks or soil.
Landscape fabric suppresses weeds. Lay down at planting time and cut slits for plants.
Some dos and don'ts:
Do not pile mulch (except winter mulches) next to plants. Do not apply mulch too heavily or directly next to tree and shrub trunks, since this may cause rotting of the trunk. You can double mulch by laying down a sheet of perforated plastic first, then adding fabric mulch, newspaper (with predominantly black ink) or pieces of cardboard and, finally, another mulch on top.
Rose and garden areas:
If roses break dormancy during warm spells in winter this will damage spring growth and jeopardize next year’s flowering. Currently, instead of deadheading pull petals off any flowers and let hips form to tell the plant to start reserving energy for winter. Do not cut back the stems/canes, however when leaves begin to change color, start at the bottom of the plant and wind the canes together with twine to keep them from breaking in wind or snow. When the ground is cold enough to stand on without making a footprint and the forecast shows cold weather ahead, pile soil over the base of the plant. After the ground freezes completely, pile mulch on the soil, especially if in an area that does not receive a high snow pack. Wait until the last possible day to add mulch, since mice and voles will burrow in and chew the canes all winter. Snow is a terrific insulator, so in those garden areas where snow pack is high in winter, you may not need any additional winter mulch.
Please join the Sage and Snow Garden Club at noon on the second Tuesday of each month in the Pinedale library. Contact us at Box 2280, Pinedale, WY, 82941, by email at firstname.lastname@example.org or call 859-8606. To find out more about the Garden Club, go to www.pindealeonline.com and click on the link under "clubs".