By Nicky Boyette – As the song goes, “Wintertime, and the gardener is mulching.” Autumn winds from Canada will have blown leaves out of trees and into your flower beds and gardens, and voila! You have mulch!
According to the Clemson University Cooperative Extension, “Mulching is one of the most important ways to maintain healthy landscape plants. A mulch is any material applied to the soil surface for protection or improvement of the area covered.” Leaves are abundant and easily available, so they are a typical mulching choice, as are grass clippings, straw, bark and other materials.
Mulch is serious business in the horticultural world. There is even a Mulch and Soil Council, founded in 1972, which creates industry standards for the bags of mulch and potting soil a consumer buys. It will have its next annual meeting in Nashville in September. The MSC created standards for labeling and product performance, but our discussion will be a less regulated and more informal, backyard view of mulching.
Kinds of mulch
There are organic and inorganic mulches. Inorganic mulches would be products such as black plastics and weed barrier cloths, which keep the soil warmer and weeds down. The gardener would need to get water beneath these, but they do help keep the soil moist. However, lots more fun than dealing with long sheets of plastic and weed cloth are the organic mulches.
Among the most available organic sources for mulch are leaves, straw, hay, pine needles and grass clippings.
If you can’t find leaves for your garden or flowerbeds, you’re not looking. Eureka Springs is a Tree City USA member, and every route out of town is through the woods. Leaves are abundant and excellent as mulch. Some larger leaves, such as oak and sycamore, are nomadic in that they will go where the wind or destiny takes them. They make good mulch, however, so it is worth the effort to keep them where they will be useful. A lucky gardener will have room for a leaf or debris pile as a repository where leaves and other end-of-year plant matter can just hang around, take some time off and eventually break down into a wonderful, tilthy mulch.
Or a gardener can find a way to keep the leaves in place. Cover a dormant asparagus bed with leaves, for example, then scatter on top some of the wonderful, tilthy leaf mulch from the bottom of the debris pile. A crafty gardener could spread leaves on a recently planted garlic bed and hold the leaves in place with an old worn-out hammock. Leaves stay through the winter, garlic sprouts uninhibited, soil is loose and friable, and the hammock pulls away easily when the time is right. Gardening is art and science.
Leaves are different. Oak leaves are generally acidic which is good for strawberries and blueberries, but not all vegetables or berries appreciate acidity. Without getting too chemical about it, a reasonable best-effort solution would be to combine all the leaves, grass clippings and compost you have. Mix it up. One for all, all for one, into the garden we go.
Pine needles stay in place well, and according to the United States Department of Agriculture, they do not make the soil significantly more acidic. They also provide a neat and tidy appearance to a strawberry bed, for instance.
Grass clippings work well because they are easy to work with and can be tucked easily around plants in beds. They keep soil moist, last through the season, and add nitrogen when they deteriorate.
Straw and hay are also effective, long-lasting mulches because they break down slowly and provide a solid cover in the meantime. However, hay farmers often use herbicides in fields to increase yields, and the bales you bring home might have residues of scary, nasty chemical concoctions. Gardeners might want to ask about the straw they buy. Uncontaminated straw does eventually break down nicely and add wonderful texture to the soil.
Ruth Stout was a renegade organic gardener who attracted the attention of other gardeners in the 1950s and ‘60s because she mulched heavily and worked only a little. She claimed after a few years of maintaining as much as seven inches of straw permanently on her garden beds, she never added manure again… just more straw. Academicians and horticulturists toured her garden to see for themselves, and she once said she got tired just hearing about all the work her guests went to raising their vegetables.
Shredded bark, wood chips and sawdust have a place in the pantheon of mulches because they are effective at keeping weeds down, but as they decompose they use up nitrogen in the soil. Therefore, to take advantage of the good part of their behavior and avoid the bad, a gardener could use them to cover pathways. Lay down a thick layer of cardboard or chipboard products such as pizza or beer boxes on the pathway and apply a healthy dose of the shredded bark. It will look wonderful and weed-free for a year or two, but then you have to do it again because weed seeds will grow on anything and beer boxes decompose. So you will need more beer boxes.
Why mulch?
Nature mulches itself. Soil in the woods beneath years of fallen leaves is loamy and easily crumbled. A gardener’s job is to take care of the soil and the soil will take care of the plants, so the lesson for gardeners is to do your garden soil a favor by assiduously adding whatever mulch you have on hand. Benefits include:
- soil retains moisture better
- soil temperature is moderated; tomato plants do not bear fruit if the soil is too hot, so mulch; a thick layer of leaves will get garlic through the winter
- soil texture improves dramatically over time; life under layers of leaves and straw begins to develop thriving economies; even under a small pile of woody stems and twigs like sage or oregano branches, living communities begin to change the texture of the soil
- decaying mulch adds nutrients to the soil
- fewer weeds sprout and the ones that do are easy to remove
- roots grow deeper with less effort
The soil here in the Ozarks is full of rocks. All sizes. Adding mulch for years will not remove them. Ruth Stout’s garden was in Connecticut and I do not remember her ever mentioning rocks. Nevertheless, our Ozark rocks do not diminish the benefits of her strategy of applying a healthy layer of mulch to our garden beds. So gather the rocks like Easter eggs, put them where they belong and replace them with…