Mulching

MIRACLE OF THE MULCH - Toby Hemenway

 

---

At first I was a tentative mulcher. Oh, I'd heard plenty about all the good things mulches would do, like conserving water, keeping the soil cool on blazing summer days, and agreeably rotting down into nice compost when its job was done. But I could only bring myself to sprinkle stingy handfuls of straw onto my raised beds. I worried about somehow choking out the plants, or attracting slugs, or accidentally growing mushrooms in the soggy straw. I'd read Ruth Stout's No Work Gardening Book, where she describes the joys of 8-inch deep mulches, but I just didn't have the courage to wholeheartedly follow her instructions. Call it fear of mulching. But I noticed that in spots where the mulch had clumped into a thicker layer, far fewer weeds reared their greedy heads. This gave me incentive and a bit of courage, so I put down about two inches of straw on all my beds. Not only did I have far fewer weeds that year, but the soil stayed so moist that I had to reprogram my drip-irrigation timer to water only every other day, not each day as in past years.

 

A few days after laying down this deeper mulch, I noticed that the straw had been tossed onto the garden paths, strewn around the garden by some evil randomizing force. It hadn't been windy, and I was baffled. I raked the straw back up, but next morning it was back on the paths. Finally I found the culprits: towhees and robins were hunting for the worms that now, since the soil was moist right up to the surface, were migrating into the straw. I gave up fighting our feathered friends, and instead just mulched the paths too. I realized the bird activity was a good sign. A large worm population builds fertility through their nutrient-rich castings, and aerates the earth with their constant tunneling. That fall I put my beds to sleep under a blanket of stable bedding, and topped that with three or four inches of straw. The soil in my garden wasn't all that good-it still bore the gooey signs of its birth as good old Douglas County clay. I had learned from some of my permaculture books about building soil with deep mulching, and this was a low-risk, off-season experiment. By late fall, about four species of mushrooms were poking out of the mulch, and by spring the straw had completely composted, while the stable bedding was just a light sprinkling of nearly rotted shavings.

Best of all, just below the surface were a zillion worms, and the soil was darker and richer than ever. This was a lot easier than composting-I only had to move the materials once. No turning the compost pile, no wheelbarrowing loads into the garden. Just toss down the mulch and wait. Emboldened by this success, last spring I started out with about two inches of mulch, and as the plants grew tall enough, I kept piling on the straw to about six inches deep. I didn't have to water until early July except for seed beds and new transplants (it was a wet spring, but I was still impressed). I barely had a weed in any of the beds. This was great! Sometimes I'd tuck clippings or nutrient-rich comfrey leaves under the mulch, and in days they'd disappear to the worms. Don't tell my wife, but occasionally I'd just shove the kitchen compost under the straw, and sure enough, it vanished too.

Something this great has got to have a flaw, and I've found one. Because the mulch is a pretty active compost pile, sometimes those helpful little decomposer organisms thriving in all that humus get confused and go after my plants. Pillbugs, in particular, sawed down my cucumber seedlings and some other small plants that have succulent stems. So I made little collars out of plastic bottles with the tops and bottoms cut off, and that thwarted the roly-polies. I had expected trouble with slugs, but so far there has been no drastic increase. Our hill is pretty dry, so you gardeners in the moister valley may have more slug trouble. Now I've scaled up my mulching experiments. On the south side of our house is a little lawn that bakes into adobe each summer, reflecting tons of heat onto the house. The grass struggling in that clay just gives up by Fourth of July, and I figured that if I can get some shrubs and trees there, the whole place will stay cooler from the shade. But first I needed to create soil in place of the clay. Sheet mulch was the answer, and I was ready to do it big-time. Here's what I did. First I sprinkled down some lime and rock phosphate. Next I laid about a quarter-inch of newspaper over the whole area, overlapping sections of the News Review so no weeds could poke through. This is my version of herbicide, one that adds carbon to the soil as well. Then I wet the newspaper, and spread out about three inches of stable manure, compliments of my neighbor Geronimo Bayard. Next came the real score: about eight inches of spoiled alfalfa hay, supplied by Rose and Ed Estrada (thanks, guys!). I topped that with more manure (which will also keep seeds in the hay from sprouting), and sprinkled enough straw on top to coat the whole pile. I'd been watering each layer as I went. Within days the whole thing was steaming: compost was happening. It's really cooking back there, and thousands of little Inky Cap mushrooms have popped up, too. What a biological riot zone! So we shall see. Ask me in the spring how it's looking-I'm pretty optimistic, but it is an experiment, so you never know. I hope to have several inches of black gold in place of a field of adobe. If it works, we can have a lot of sheet-mulch parties: it's much more fun with friends.

Return to Newsletter Page