About Mulching

Mulching is one of gardening’s oldest techniques. The English word was probably derived from the German vernacular, molsch, meaning soft and rotten. It is probable that mulch in olden days was a litter of straw that farmers and gardeners used to keep the soil cool and moist.

Mulches imitate the layer of fallen leaves and dead plants that cover the ground in wild settings. They insulate the soil from the temperature changes and drying of the atmosphere. Without a mulch, the soil surface gets very cold on spring and fall nights and very hot during hot weather. It loses its water rapidly to the dry air and becomes inhospitable to plants. During hot weather, plant roots growing in the top few inches of soil exposed to the sun die from overheating and drought.

Soil under a few inches of mulch remains at near the same temperature day and night. Because the mulch traps dead air above it, that air quickly becomes saturated, preventing further evaporation. With moisture and agreeable temperatures, plant roots can utilize the soil right to the surface. Sometimes they even grow into the mulch. For this reason, adding a few inches of mulch has the effect of giving your plants deeper soil to grow in.

Mulch comes in a wide variety of forms, textures and colors, from pebbles and rocks to wood chips to cocoa beans. While each has its advantages, choosing and using a mulch is a great way to improve your garden, keeping soil moist and cool to help encourage healthy plants.

Why Mulch?

Weed control

Since they will be denied light, weed seedlings will not grow.

Temperature control

Mulches insulate plants from drastic temperature changes.

Attractive appearance

Mulches provide a neat, uniform look to your landscaping.

Moisture retention

Mulches reduce the speed of water evaporation while keeping an even supply of water on the upper levels of the soil.

Prevention of compaction

Mulches break the fall of water drops, which can cause the soil to compact and inhibit plant growth.

Soil texture improvement

The soil underneath the mulch benefits as well. For example, clay soils get improved aeration, and sandy soils retain water better.

When deciding on a mulch for your lawn or garden, remember these mulch recommendations:

  • Mulch should be long-lasting and not easily washed away by rain.
  • Mulch should have a loose structure that allows water to pass through it quickly.
  • Mulches and barks differ in texture and color. Choose what’s best for you.
  • Pebbles, rocks and gravel can make useful and attractive mulches. However, they do not shut out light entirely, so weed seeds may germinate beneath them.

Applying Mulch

  • Late spring is the best time to apply mulch. This will help reduce soil temperature and save water. An early spring application will slow the natural warming process of the soil.
  • Fine mulches should be applied 1 to 2 inches deep. Coarse or fluffy mulches should be put on 3 to 4 inches deep.
  • Apply the mulch evenly. Level it with a rake or your hands. Don’t pack it down.
  • After application, wet the mulch thoroughly, then pull it back a few inches from the stem or trunk. This allows adequate air circulation to the base of the plant.

How Much Do You Need?

Depth of mulch Coverage: 2-cu-ft bag Coverage: 3-cu-ft bag
4 inches 6 sq. ft. 9 sq. ft.
3 inches 8 sq. ft. 12 sq. ft.
2 inches 12 sq. ft. 18 sq. ft.