Last week I invited Lindsey out to help weed the raised beds. About half of them had a couple inches of bark and sawdust on them, which I’d spread around the tomatoes and squash. The rest were mulch-free. Other than the mulch, the beds had been treated exactly the same the years before; that is, they were top-dressed with an inch or two of manure.
After the proper amount of motherly persuasion, Lindsey accepted my invitation, and we weeded the bare beds first. By the time we were ready to begin the mulched beds, it was warming up, so I took off my sweatshirt and draped it over the grape trellis and worked bare-armed.
“Look,” Lindsey said. “The part that was covered is much moister, and the color and texture are so much better.”
“That’s why I always warn you to wear sunscreen.” I put my sun-browned hand on my white arm. “See the difference?” I asked.
“You need lotion,” Lindsey said. “Too bad your brown hands aren’t as rich as this mulched soil.”
And it was. It was dark brown and earthy, and moist all the way to the surface. The texture was granular, the way the best soil is. The other beds were greyish and dry on the surface, although they looked richer when I dug in. The unmulched soil was also caked, and didn’t accept moisture very well. Mulch, especially organic mulch, is a boon to gardens everywhere, but especially to Nevada gardens.
Inorganic mulches have their place. Decorative rock is useful where you don’t wish to plant, or where you have heat-tolerant shrubs. It’s best used with weed-barrier, because few things beat up your hands like digging weeds out of gravel. Black plastic warms the soil quickly, and is useful for plants which really love heat, like sweet potatoes.
However, only organic mulches improve the soil. Grass clippings, leaves, bark, straw, hay, shredded paper and coffee grounds are all useful. Ed Klemish once told me the best thing he ever put on his garden was rotten alfalfa hay.
Although organic mulches do eventually add nitrogen to the soil, they will also absorb nitrogen as they decompose. If the mulch is on the surface of generally rich soil, it won’t rob your plants. I’m a lazy gardener, so I won’t turn the mulch under, but if I did, and the mulch was not at all decomposed, I’d add some manure or good compost with it, or give it time in moist conditions to rot.
If you add another layer of mulch every year, and perhaps a bit of manure, there should be no need to dig your garden. Mulch not only prevents soil from drying out, it also helps to avoid run-off in a couple of ways. It physically impedes the water, and it preserves the tilth, or springiness of the soil. Tilth allows air and moisture to penetrate the soil.
But wait—there’s more. Organic mulch helps level out temperature extremes in the soil. Mulched soils will be cooler in the heat of the day and warmer during the night than bare soils. Most garden plants like to avoid those temperature extremes.
Because they are cooler and moister, mulched soils encourage our little buddies, the earthworms. That’s probably why the texture of the mulched beds is markedly better.
Lindsey wants me to tell you that the absolute best thing about mulch is that it helps prevent weeds, and the weeds that do grow will be much easier to pull, since the soil will be looser and moister.
Now that Lindsey can spend less time weeding, I can introduce other chores. I’ll try to think of something for her to do while she finishes up the laundry and does the dishes.
When Teresa Howell is not trying to decide if she should give up lotion and just mulch her hands, she teaches English at Great Basin College.