Not much beats mulch for retaining soil moisture in a dry climate like New Mexico’s.

Mother Nature covers the ground under plants with their cast offs, so humans would be wise to leave them there.

So what exactly is mulch? Mulch is often confused with compost, which is the dead remains of living matter that have been digested by microbes, insects, worms, and fungi to create rich soil. Mulch is simply any ground cover. This protective layer could be leaves, straw, wood chips, grass clippings, pecan shells, newspaper, black plastic, or even rocks that are placed around the base of a plant.

Reasons to use mulch:

  1. Slow the evaporation of water.
  2. Cool the ground around the roots in summer.
  3. Prevent the roots from freezing in winter.
  4. Discourage weed seeds from sprouting or finding light.
  5. Decorate or define planting areas.
  6. Keep soil and soil-borne diseases from splashing onto plant leaves during rain or watering.

Factors affecting your choice of mulch material:

  1. Price – what you can access for free or find readily available will be a tempting choice.
  2. Weight – if the land is sloping, a heavier mulch will stay in place better in wind and rain.
  3. Color – a dark mulch will retain more heat than a lighter mulch, and some folks like to expand the outdoor palette or give distinct areas contrasting colors.
  4. Durability – clearly rocks last longer than newspaper, but they’re also harder to get rid of if you change your mind.

Cautions and considerations include:

  1. Weed killers in the mulch (such as in grass clippings) could kill your plants, so know your source.
  2. Overheating of the ground and die-off of soil life may occur when black plastic is used.
  3. Colored dyes in newspaper or magazines rarely contain lead these days, so no worries on that front.
  4. Soil compaction from a heavy mulch such as river rock on clay can block root growth.
  5. Seeds in straw or especially hay can sprout in mulched beds.
  6. Matting of unshredded materials may prevent moisture from penetrating to the root zone.
  7. Weed barrier (aka landscape fabric) sheds microplastics into the soil that plants then take up.

Free sources of wood chips are:

East Mountain Transfer Station, 711 NM-333 in Tijeras, 505-281-9110, open 7am-5pm every day. You can load yourself or pay them $5/scoop.

ChipDrop puts you on a list that tree trimmers will call if they come to your area. You have to take their whole load, which could be as much as ten cubic yards.

—If you or a neighbor has a tree trimmed or removed, you can ask the arborist to leave the chips in your driveway.

by Donna Deitweiler