CO-Horts Blog

Monday, November 29, 2021

Don't Forget About Mulch!

If there is one tip I could give for just about any landscape situation, it would be mulch. Mulching is a great thing to do for your soil and your plants, and a great natural way to keep weeds down. There are many types of mulch and using them correctly can be beneficial for many reasons.
A mulch is a material that is applied to the soil surface. Mulches function to protect and improve soil. Different types of mulch have different advantages for your landscape. Generally speaking, mulches reduce the amount of moisture that evaporates from the soil, which conserves water. Mulching a planting bed can reduce the need to water by 50%. Mulches also stabilize soil temperature. This can be beneficial for shallow rooted plants that are susceptible to freeze damage during the winter. Many mulches will help improve the structure and fertility of the soils they are added to. For some types of mulch this may require mixing them into the soil at some point during the year. One of my biggest gardening battles has been with controlling weeds. Mulch can inhibit the germination of weed seeds, which is a big help! Your trees will also benefit from mulching around the trunk. Trees that have mulch around their trunks grow larger and healthier than trees that have turf growing all the way to their base. The mulch “donut” should be two to three feet wide. Leave two to four inches of bare ground near the base of the trunk, if it is touching the trunk it increases the chance of your tree suffering from girdling roots. There are two categories of mulch, organic and inorganic. The difference between the two is that organic mulches were once alive, and inorganic mulches were not. Grass clippings are an easily obtainable organic mulch. They are perfect to mulch a vegetable bed. Add a 1/4-inch-thick layer and let it dry before adding the next layer. Adding a couple sheets of newspaper (avoid glossy sheets) under the clippings will give extra defense against weed seeds. Make sure you are not using clippings that have been treated with herbicides, which can be harmful to your vegetable plants.
Wood chips are another popular choice of organic mulch. They are good for areas that do not need the soil worked every year, such as between raised beds or in perennial plantings. They are better suited for the soil surface, working them into the soil (without composting them first) can tie up soil nitrogen, leaving an insufficient amount for your plants.
Pea gravel is an example of an inorganic mulch. It is visually appealing in a landscape area where you don’t have plants, or where your plantings are permanent. It can cause heat to build up around plants, however, which may increase water requirements, so it is better suited for water wise, heat tolerant plants.


  1. Your blog confirmed that I’m using my grass clippings, wood chips, and pea gravel in the right places! Thanks.

  2. How thick or deep should wood chip mulch and rock mulch be applied?