Mulch Matters in your Garden
By Mallory Kelley
Regional Extension Agent
Mulch for your Landscape
Mulch is a natural process that occurs regularly in nature with fallen leaves, twigs, and spent flowers. There are so many benefits to using mulch and they provide a protective covering for the soil and keep your garden and landscape healthy.
Mulches can be in the form of organic or inorganic. Organic mulches are made up of plant material and will decompose and become part of the soil. Organic mulches must be replenished periodically due to their rate of decomposition. Inorganic mulches are not composed of plant material and are often seen in the form of plastics or rock type formations.
Mulching helps the soil hold moisture and helps prevent weed seed germination. Mulches also help keep the soil cooler and when mulch decomposes it increases organic matter which helps with soil aeration and water absorption.
Organic mulches are less expensive and can be created through leaves and grass clippings that are already present in your landscape. Bark mulches or wood chips are made from different types of trees and are very attractive in the landscape. These mulches have a slow decomposition rate, but should not be used next to foundations as they can attract termites. Other types of organic mulches include, leaves from your trees, grass clipping, pine straw, and even old newspapers.
This year there has been lots of interest in using newspaper as a mulch in the landscape and in the vegetable garden as a weed barrier. This is a great idea as it also helps enrich the soil as the newspaper breaks down over time, but it also helps retain moisture. When using the newspaper use multiple sheets or even a whole section of the paper at a time (6-10 pages thick) for the best weed control especially throughout the summer months when weeds are most prevalent.
Inorganic mulches such as gravel, crushed stone, and plastics are more expensive, but are permanent additions to the landscape. They come in a variety of different colors, textures and materials. These inorganic mulches can add a great element to the landscape, but keep in mind that these types of mulches will be much warmer in the summer months removing more water from the soil and can scorch nearby plants. Plastics are good inorganic mulches, but can cause the soil to remain too wet resulting in root disease problems. Black plastic is not very durable and tends to break down quickly. It is often a good idea to cover plastic mulches with a thin layer of pine needles or wood chips to help slow down the decomposition of some plastics and also to help keep the plastic cooler in summer months.
Tips to most efficiently use mulch in your landscape:
- Always remove existing weeds before applying mulch.
- If applying mulch in the fall, wait until the soil has cooled before applying as this can encourage weed seed germination.
- Keep mulch depth uniform throughout your planting beds and around trees (2-4 inches for organic and 1-2 inches for inorganic mulches).
- Never let mulch build up around the trunk of trees or shrubs. After a few years of mulch application if you see this buildup occurring rake away old mulch and apply a new layer.
- If the mulch starts to smell like vinegar, ammonia, sulfur, or silage the mulch has gone bad. The smell is unpleasant in the landscape and can damage your plants. To cure this problem in your landscape turn the mulch once or twice a month- Good aeration should eliminate the problem quickly.
For more information on mulches for your landscape or garden please visit one of the following sites: