Bugs From Mulch

Decomposers

• Organic mulch materials decompose into an earthy, black, soil-like substance called humus or compost. Bugs and insects called decomposers break down bulky mulch materials. Moisture in the mulch layer attracts sow bugs, millipedes, earwigs and centipedes. In a compost pile, these creatures and others do the important job of creating the smaller pieces of material that become compost. Layered mulch in the garden turns into composted material faster during rainy periods when the soil is moist.

Bugs That Like Mulch

• Common bugs attracted to mulch as a food source are rove beetles, ground beetles and lighting bugs. A mulch layer provides the right environment for the lightening bug larvae to hatch and grow. These are beneficial insect predators that eat harmful insects. However, cutworms, slugs and snails also hide under mulch layers, coming out at night to eat plants. Pulling the mulch layer away from a plant base helps eliminate this problem.

Mulch Layer Depth

• Two to 3 inches is the depth most often recommended for finely shredded mulch layers and 3 to 4 inches for bulky materials, such as chipped wood. Layers of organic materials, such as dry leaves or straw, circulate enough air to prevent the development of insect problems. The ideal mulch layer allows water and air to enter and exit the soil. Heavily compacted mulch releases chemical compounds that damage plant roots. Compacted mulch also encourages bug infestation.

Grass Mulch

• Bugs and insects are attracted to mulch made from grass clippings if unmixed with compost or dried leaves. Grass clippings are a beneficial nitrogen source for plants and soil but easily become compacted. The nitrogen-based heat and ammonia released by fermentation kills or injures nearby plants. Allow grass clippings to dry before using them as mulch and do not use clippings exposed to herbicides.