The Earth: Mulching

In my fields, I have practiced mulching for many years and have become a believer in its benefits. I have found that it keeps the soil moist and friable, uniform in temperature, and easy to work. It also helps keep the rain from splashing mud on plants, the ground moisture from evaporating, and weeds from growing. Every garden needs a little mulch.

Mulch is a layer of material, organic or inorganic, spread on the ground near plants or in the aisles. It protects the soil from the effects of the wind, rain, and the hot sun. During a long dry spell, I get by with a lot less watering. Mulch moderates the soil temperature keeping it a little cooler in summer and warmer in winter. The best part is that it cuts down on the time spent on garden upkeep.

Materials Used

Any number of materials are used for mulch – grass clippings, paper, straw, sawdust, or polyethylene black plastic film. I prefer to use organic materials because they can be incorporated in the soil after the growing season, thus adding valuable nutrients.

The Earth: Mulching 1

  • Grass clippings are one of the best and most commonly used mulches. When they decompose, they leave nitrogen in the soil. Clippings must be left to dry for a day or two by spreading them in the sun before they are used. If they are fresh and moist they will mat and rot, becoming slimy and foul smelling.
  • Newspaper is great when used under other mulches. Never use newspaper by itself because it acts as a wick and pulls moisture from the soil. I place four sheets of newspaper (black print only; colored print has toxins in it) on the area I want to mulch. I then spread the grass clippings or straw on top, covering the paper completely. When paper is used, only two or three inches of an other material are placed on top. Huge quantities of mulching material are not needed. Newspaper, used with a mulch, is also good because the paper will block weeds from coming up through the mulch. Any seeds in the mulch material will not go down into the soil to sprout.
  • Straw is a good mulch, but weed seeds may come with it. This is why paper under the straw will save a lot of headaches. Avoid hay as mulch — usually it brings weed problems.
  • Sawdust is an excellent mulch, but must be partially decomposed before applying. Otherwise it will deplete the soil of nutrients as it breaks down. If fresh sawdust is used, apply extra nitrogen to the soil under the sawdust. I use newspaper instead of nitrogen under the fresh sawdust.
  • Black plastic does not build the soil or contribute nutrients, but it does deter weeds and conserves moisture. Rain does not penetrate this material, so drip irrigation must be placed under it. A problem with black plastic is that it tends to absorb the heat of the sun and raise the soil temperature – sometimes very high. A layer of straw or grass clippings on top of the plastic will help.

The initial cost of these mulches is offset by the fact that they can be recycled from year to year.

Special Benefits of Mulch:

  • Insect Barrier – Some insects, including the Colorado potato beetle, striped cucumber beetle and spotted cucumber beetle, will avoid a mulch of straw.
  • Water Conservation – Many times conserving water will be as important as watering the crops. During July or August dry spells, make sure the garden loses as little water as possible. Mulching helps protect bare soil from evaporation.
  • Erosion – A layer of mulch will protect your soil from rain that causes erosion.
  • Weeding – Mulching prevents weeds from growing. Weeds need light to grow and mulch shades out the light.

Do’s and Dont’s of Mulching

  1. Mulching too early in the spring keeps the soil from warming up and encourages rot during excessively wet periods.
  2. Wait until the soil has warmed up in the late Spring, then put mulch on the spring crops. This will help to delay bolting.
  3. Mulch the summer crops late in June when the soil has warmed and will continue to remain warm. This prevents the soil from becoming hot and dry. Mulching will keep the soil at an even temperature around the plant roots.
  4. Leave a gap between mulch and plant stems for air circulation.
  5. The best time to mulch is right after a rain.
  6. If the mulch is left on over the winter, it will encourage earthworms and beneficial microorganisms. They will eventually devour the organic mulch and turn it into good humus

At the end of the season, when the mulch is turned into the soil, it will be broken down and continue to enrich the soil’s humus content.

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