Gardening with Laurie: Compost, mulch are not the same thing

By Laurie Garretson
July 10, 2014 at 2:10 a.m.

Laurie Garretson

Laurie Garretson

Two words most often misused in the gardening world have to be compost and mulch. People frequently confuse mulch with compost. While compost can actually be used as a mulch, it is more times used as a soil amendment. Mulch is anything that can be used to cover the surface of soil in your landscape.

Mulch can be organic, like shredded leaves, or inorganic, like old shredded tires. There have been lots of research throughout the years to test different types of mulches. It is usually found that organic mulches perform better than inorganic mulches.

Inorganic mulch will not add anything back to the soil like organic mulches do. Consequently, it cannot improve the health of the soil. Rubber mulch made from recycled tires can leach toxic heavy metals into the soil and runoff water. Inorganic mulches can provide some of the benefits that organic mulches do, such as reducing weed growth and retarding water loss.

Organic mulches come in many sizes and from many sources. Shredded forms of organic mulches tend to bind together and work well on slopes. Smaller pieces of bark nuggets or chipped up wood work well in beds planted with tender annuals or perennials. Larger pieces of organic material, such as large, decorative bark, work well in windy areas and in large planting areas.

Different colored, dyed mulches are the newest forms of mulch on the market. It's been discovered that when black-colored mulch is used in a sunny area, it absorbs enough heat and raises the soil temperature enough to burn the lower growing foliage on plants. This heating action could be beneficial in the case of warming the soil for fall tomatoes, for example.

The point is to know your options when choosing what to cover your gardens and beds with and to remember just how important mulch is. Mulching will reduce your water needs. With the soil covered, there will be less evaporation, which means mulch will reduce your water needs.

The soil's temperature fluctuates less when mulched. Mulching keeps the soil cooler in the summer and warmer during cooler months. This action makes for healthier root growth and overall healthier plants.

Weeds will be much less of a problem for gardeners who mulch all their beds and gardens. Keeping sunlight from the soil greatly reduces weed seeds from sprouting, and those that do sprout will be much easier to remove.

Mulching helps prevent the soil from crusting. Crusting is when the soil literally forms a hard, shell-like coating on the surface. Crusting causes water to run off rather than be absorbed into the soil.

Organic mulches are a very important part of an organic garden. With time, organic mulches will improve the microbial activity in the soil, improve the nutrient levels, improve the structure of the soil and improve many other factors of the soils overall health.

Until next time, let's try to garden with nature not against it, and maybe, all our weeds will become wildflowers.

Laurie Garretson is a Victoria gardener and nursery owner. Send your gardening questions to or in care of the Advocate, P.O. Box 1518, Victoria, TX 77902.



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