Mulch Wisely This Spring

By Chris Williams on April 13, 2016.

Pests love shredded hardwood mulch. We’ve said it before and we’re saying it again, hopefully in time to prevent the mulch pileup that happens when gardeners undertake their spring chores. You can have that clean, landscaped look that mulch provides with 2 inches of mulch just as well as with 6 inches, and you’ll save money, too.

Why is Too Much Mulch a Pest Problem?

Organic mulch holds moisture. Foundation pests love moisture. Many of them can only survive in damp environments. After a heavy rain or even after lawn watering, it takes a long time for 6 inches of mulch to dry out and that keeps pests happy (see Pests in Mulch).

Mulch provides a food source. The other thing pests love about wood mulch is that it’s organic and for some pests, provides a food source along with the moisture. Many of the foundation pests that live around the perimeter of our homes (earwigs, pillbugs, millipedes, cockroaches, crickets, etc.) feed on decaying organic material and rotting wood mulch qualifies. Some insect predators live in mulch just to feed on the many other insects taking shelter there.

Termites appreciate a good mulch border, too. Shredded wood mulch allows termites to survive around the foundation of your home because it provides the moisture they require. A thick mulch layer can also allow termites to bypass any termite soil treatment as they can move through the mulch to reach your home instead of having to tunnel through treated soil.

If You Must Mulch, Mulch Wisely to Avoid Pests

  • Go lightly on the wood mulch; all you need is 2-3 inches after settling (see Apply That Mulch With Insects in Mind). Make sure that mulched areas don’t remain wet from downspouts or sprinklers.
  • If you want to apply mulch thickly, at least pull it away from your house. Leave a 12 to 24-inch deep, dry, mulch-free border around your home’s foundation.
  • Consider an alternative to wood mulch or other organic mulches. Inorganic mulches include gravel, pebbles, rock chips, woven landscaping fabrics, and probably newer, shredded things that we haven’t heard of yet. Inorganic mulches offer no food and less protection for pests.

Photo Credit : “Mulch-soil filter for greywater treatment (2921680616)” | CC BY 2.0 via Wikimedia Commons.



We’re not satisfied until you are. Learn More