Fall has officially arrived. Around here, that means getting my garden ready for a long winter’s nap. Of course there are all of the typical fall chores – removing dying annuals, planting spring bulbs, cleaning out iris and daylily beds, draining hoses, putting tools away – but this year there’s going to be a new task on the fall list. From now on, I’m going to be adding mulching to my fall chores.
There are two broad categories of mulch, inorganic mulch and organic mulch. Inorganic mulches consist of non-living materials such as geotextiles (landscape fabrics), plastics, rubber mats and stone.
Inorganic mulches are long-lasting. Beds covered with landscape fabric and rock, for example, tend to stay intact and rarely need more than a quick top-dressing to retain their appearances. Plastic sheeting or rubber mats used as mulch do not allow weeds to burst through, keeping beds weed free but unnatural in appearance. Unfortunately, their impermeable surfaces also keep moisture and oxygen from reaching the soil below, robbing plants of nutrients necessary for long-term survival. Both plastic and rubber mulches also have another drawback. They both degrade over time, leaching plastic and polluting chemicals into our water systems.
Organic mulches are made from a wide variety of living materials. Wood, straw, grass clippings, cocoa hulls and compost are just a few of the more common ones.
Organic mulches are, by their very nature, relatively short-lived. They tend to break down within a season or two, so they do need to be periodically replaced. As they break down however, they add essential microbes to the soil, which eventually results in healthier, more productive soil. Using the right organic mulch for the situation and applying it correctly, organic mulches not only let water seep through to the soil underneath, they can also be effective at preventing weeds from taking over.
Here in the Midwest, our winters are changing. We are experiencing unusual extremes in both temperatures and moisture levels. One day, we can wake up to below zero temperatures and a foot of snow covering everything in sight. Over the next few days, temperatures can soar into the 50s and 60s turning the snow-covered ground into mushy bogs.
Cycles of freezing and thawing can cause plants to heave out of the ground, exposing delicate root systems to harsh air temperatures. Tender perennials and newly planted ornamentals typically cannot withstand this damage to their root systems and will often die. A layer of mulch applied in the late fall, can help to keep ground temperatures regulated and minimize the effects of freezing and thawing moisture in the soil.
Another scenario that is becoming common here is a winter with warmer temperatures but without much precipitation. Having a layer of fresh, fall-applied mulch will help keep any existing moisture from rapidly evaporating. Adequate moisture throughout the winter gives plants a more successful start in the spring. (As an aside, make sure that your plants go into the winter well-watered. Plants going into winter stressed from a dry fall have difficulty coming back in the spring.)
Finally, a layer of mulch applied in the fall can help prevent weeds from popping through in the early spring.
The barrier that several inches of mulch provides limits the amount of sunlight newly sprouted weeds receive, which cuts off photosynthesis and limits their growth. Beds are cleaner to begin the spring season.
While I love the crisp, clean look of a freshly mulched bed in the spring, I’ve come to realize that the benefits of fall mulching outweigh the aesthetics of spring. Besides, the idea of a newly mulched landscape as a backdrop to winter is appealing too!