Mulch in the Landscape

Mulches are useful for a number of purposes: Through the summer growing season, use mulch to conserve water, to keep the soil cool, and to keep out weeds; through the winter, use mulch to protect roots and stems from winter injury; In early spring, a dark composting mulch can help to warm the soil. Using a dark mulch in sunny areas may warm the soil if it is not spread very thick.

Mulches conserve water: Using mulch reduces the evaporation of water from the soil. Mulch absorbs rainfall, preventing runoff and allowing for better penetration of water from heavy rains into the soil. Mulches also save water by reducing competition from weeds. With the improved moisture conditions, your garden will need less or even no supplemental watering during dry spells.

Mulches regulate soil temperature: Mulches can either decrease or increase soil temperature. Loose materials such as mulch act as an insulating layer and reflect heat and prevent sunlight from reaching the soil. The insulation results in cooler soil temperature. Thin layers of dark mulch can increase soil temperatures. The insulating action of mulch also aids in preventing heat loss during extreme cold spells in winter.

Mulches provide weed control: Proper mulching, deep and dense enough to prevent light from penetrating down to the soil surface, will keep weeds from germinating.

When to spread mulch: Spread your mulch over the soil after your plants are well established and when the soil is warm enough to promote active root growth.

When to remove winter mulch: Remove mulch before the growing season begins; this will allow the sun to begin warming the soil. For late snow melts, remove mulch as soon as the snow has melted. Most protective uses of mulch serve to protect plants with tender roots and stems from harsh winter cold spells.

Re-mulching during the year: Because mulch compacts as the season wears on, you may have to add additional mulch to keep it thick enough for your purposes. You will not have to scrape off existing mulch in midseason, just spread more mulch over the existing layer.