A few years ago, a gardening friend suggested I place a layer of compost in my flower beds before mulching with my usual shredded bark mulch. As my garden seemed happy and required less care that summer, I continued using compost between the soil and bark until one day I just stopped using the shredded bark top layer altogether. Rich in organic matter and beneficial bacteria, compost is traditionally used as a soil amendment, but it makes a fine mulch as well.
Most materials typically used as mulch do not greatly affect the organic makeup of the underlying soil. Compost is different. It improves the texture and nutrient content of the soil and contributes beneficial bacteria as it provides the protection of a mulch.
Top-dressing with compost can really simplify your gardening routine. I begin in the spring by pulling the previous season’s application away from the base of plants to allow the soil to warm. Once things are growing nicely, I work the old compost into the soil, pull any visible weeds and add a 2-to 3-inch layer of fresh compost. It is best to leave a little space around the stems or crowns of plants to allow for air circulation and prevent rot. If you like the look of shredded bark or wood chips, a thin layer can be added on top of the compost.
Other than freshening up areas of mulch that become bare during the summer, deadheading spent blooms and, of course, watering during the Texas heat, I do not have to put much effort into keeping beds tidy and nourished throughout the summer. When using compost as mulch, I find that most of my plantings are happy enough without the use of additional fertilizers and, provided the compost has been “cooked” properly, weeds are minimal.
After tidying up spent foliage in the fall, I lay down a little extra compost to help protect roots from winter damage and give a boost to winter growers. Following this simple regimen has yielded great results in my garden as most plants seem to appreciate the slow, steady release of nutrients that decomposing compost provides.
I hope you will give mulching with compost a try. To learn more about the benefits of different types of mulch and making your own compost, visit aggie-horticulture.tamu.edu.
The Smith County Master Gardener program is a volunteer organization in connection with the Texas A&M AgriLife Extension Service.