To mulch or not to mulch? Each year I consider whether to take that extra step.
Mulch is a protective covering applied to the soil’s surface. A tree shedding its leaves on the ground, where they decompose and thereby add nutrients to the soil, is the prototypical mulcher. Gardeners and farmers mulch too, for diverse reasons.
The No. 1 benefit, according to Patricia Rowe-Dutton’s classic 1957 book “The Mulching of Vegetables,” is conserving moisture. Mulch applied to moist soil will help keep it that way, so you’ll irrigate less. I’ve heard it said that a good mulch gives plants the equivalent of four inches of rain as they grow — moisture that is captured and not lost to evaporation.
Mulch also has a steadying effect on soil temperature, keeping it warmer at night, cooler by day. This is a plus for hot-climate gardeners growing lettuce, but tricky for cool-climate ones ripening peppers, who should mulch only after the ground has warmed up. Mulch can offer winter protection for tender plants. A mulch of natural materials enriches the soil as it decays, just as with that leaf-dropping tree.
For me, mulch, above all, discourages weeds. Every spring, as my garden has annexed a bit more of the yard, I’ve made a delusional vow to keep it weed-free with regular cultivation. But the only sure-fire solution has been mulch.
My perennial beds grow bushy early on, and they soon shade out most weeds. The shrubs are permanently mulched with shredded bark or leaves. But beds of annual crops are vulnerable to annual weeds that carpet them with seedlings. Rowe-Dutton, in her “Index of Mulching Materials,” lists more than 50 things used to cover the soil. Some are a little bizarre. Aluminum foil? Slate roofing tiles? Asphalt paper? (I think we’d call that tar paper today.) In any case, I don’t want them in my garden.
Sometimes I’ll see a stack of newspapers or catalogues bound for recycling, and wonder if I should pave a garden path with them. But in the end the only mulches I like are natural ones, pleasing to look at and beneficial to the soil.
There are many such coverings to choose from. Pine needles are elegant if you have a good supply. Peat moss is easy to apply but tends to crust over. A light mulch of grass clippings soon loses its bulk but is good for a quick crop of bush peas. Spread it too thickly, and it develops a strong silagelike reek.
My favorites are hay and straw — whichever is most affordable and easy to find. Of the two, hay, which is field-grown grass cut before going to seed, puts more nutrients into your garden’s soil. Straw — the stalks that are left standing in the field after the hay has been cut and harvested as a secondary crop — is less likely to contain seeds of grass or weeds, but costs more. Look for bales of both at garden centers, feed stores, in classified ads and through the gardening grapevine. Apply in fistfuls or in flakes, the booklike pages that open up when you cut the strings from a bale. Check the soil beneath from time to time. Most likely it will be dark, crumbly, alive with tunneling earthworms and scurrying beetles, and grateful for that extra four inches of rain.
