Fall for the Benefits of Mulch

Mulch is a natural way to enhance organic matter and retain moisture in urban soils. September is a great time to add it to your landscape.

There’s much to love about mulch. It’s a natural way to enhance organic matter and retain moisture in urban soils, it’s available in both organic and inorganic forms, and in different shapes and sizes.

Most people think of mulch as raw or partially decomposed pieces of wood or bark. While this is true, mulch can also consist of black plastic, straw, pine needles, pecan shells and decomposed granite.

All mulches reduce soil moisture loss, but I prefer organic varieties because of the carbon they add to the soil. Carbon is the energy food for all micro and macro organisms living in the soil and essential for the health of the environment.

Inorganic mulch like decomposed and rolled granite are added to the landscape with the assumption they facilitate drainage for xeric plants or reduce maintenance. But that’s not true. They seldom provide any nutritional benefit and actually increase urban heat, flooding and maintenance so we very rarely recommend inorganic mulches.


mulchOrganic Mulches

  • Hardwood chips or shreds
  • Bark chips or shreds
  • Pecan shells
  • Straw
  • Pine needles

Inorganic Mulches

  • Rock of various sizes
  • Decomposed granite
  • Black plastic
  • Rubber chips


What else can mulch do for you? Mulch reduces soil temperature to facilitate root growth, inhibits weed germination and growth, provides soil structure that allows air and water to penetrate, and encourages beneficial soil organisms like bacteria, fungi and earthworms.

We strongly advise applications of one to two inches of mulch in May and September to achieve maximum benefits, so now is a great time for that application. Your locally owned nursery has just the product for your landscape.

Picture of Mark Peterson
Mark Peterson
Mark A. Peterson was a conservation project coordinator for San Antonio Water System before retiring. With over 30 years of experience as an urban forester and arborist, Mark is probably the only person you know who actually prunes trees for fun. When not expounding on the benefits of trees and limited lawns, you're likely to find him hiking San Antonio's wilderness parks or expounding on the virtues of geography and history to his friends.
Dig Deeper

Find expert advice on garden basics, landscape design, watering and year-round maintenance.