By Denny Schrock, Colorado State University Cooperative Extension agent, horticulture
Cut down on water use in the vegetable garden. Reduce weeding to a few minutes a week. Harvest tomatoes and cucumbers weeks before your neighbors. Protect vegetables from disease problems. All this from one amazing product.
This marvel is mulch.
Mulch in the vegetable garden helps retain soil moisture by cutting down on surface evaporation. It also protects soil structure by decreasing compaction from pounding rains or overhead irrigation. Disease problems often are fewer in mulched gardens because soil that contains disease organisms no longer splashes on plants.
Organic materials such as straw, hay, shredded leaves or grass clippings work well as mulches. You can apply dry materials such as old hay three to six inches deep. If you use fresh grass clippings, use only a thin layer each time to prevent them from matting down and developing an unpleasant odor. Also, make certain clippings come from a lawn not recently treated with weed killers. (If weed killers have been used, compost the clippings first.)
Wait to apply organic mulches until about mid-June. In addition to preventing most weed growth, they insulate the soil from the sun's warming rays. Early in the growing season, seedlings benefit from additional warmth, so allow the sun to thoroughly heat the soil before adding a covering of mulch.
Certain warm-season crops such as tomatoes, peppers, cucumbers, squash and melons take all the heat available in this area. Plastic mulch is the answer for them. Clear polyethylene warms soils best, but it also permits weed growth under the plastic. Black plastic keeps weed growth in check and still provides some warming to hasten vegetable maturity.
Plastic mulch is most easily applied before planting. Drip irrigation lines placed under the mulch make watering easy. Cover the edges with soil to keep the sheet in place. Transplant or direct seed vegetables through small slits cut in the plastic. If plantings are already started, gently pull the established plants through slits in the plastic or place strips of plastic around the plants.
The small amount of effort required to mulch the garden is readily repaid in time and money saved from less weeding, less watering and less produce lost to disease.
Photo: Judy Sedbrook
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010