Mulch Can Cover A Multitude of Sins As Well As Weeds

From Gene Logsdon
Garden Farm Skills

Sometimes I think that Ruth Stout, the Queen of Mulch in the early days of organic gardening, did more to hurt the practice than to help it. She made it sound so easy and carefree. That’s okay because I daresay she persuaded more people to start gardening than any other single writer at that time. We all rushed out to gather up leaves and grass clippings from the four winds to pile on our gardens and then, tra la la, fell back in our hammocks and waited for harvest. Ruth put gardening on Easy Street.

As the old song puts in, “it ain’t necessarily so,”  as we all found out. Mulching is one of the very best gardening practices, but like everything else, you have to master the details if you are hoping for quality time in the hammock.

The rule of timing: The sin that mulching so often covers, in addition to weeds, is cold wet soil from applying the stuff too early. Do not start mulching until the soil has warmed up completely. I suppose on pure sand or in the deep South, this rule is not as critical, but whatever, especially on clay and loam soils, you will experience much grief if you layer on the mulch early in spring or worse, put it on late in fall or through the winter under the mistaken notion that you are protecting the soil from winter’s cold. The soil benefits from winter’s cold.

Mulching too early means you can’t work up a nice seedbed until late in the spring.  Transplants set into cold, mulched soil will sit there, blue and shivering, until July. I am talking now about organic mulches— hay, leaves, straw, grass clippings etc. Black plastic “mulch” can be put on early, and it will help warm the soil up. But that’s a subject for another time.

Here in northern Ohio, (you can make your own determinations accordingly), we do not put on organic mulches until June and then aren’t in a hurry. Right after a good rain is the best time, so as to prevent that moisture from evaporating into the air. Mulching in a normal year can take the place of watering. In a dry year, it can cut watering by half.

First we mulch early vegetables, perhaps even a little before June, especially leafy vegetables so that rain doesn’t bounce mud on them. Then comes the twin pole bean rows where the vines are climbing wooden poles anchored to a center wire overhead. That means a sort of tunnel underneath, impossible to get to with the tiller and hard even to hoe. Then we do potatoes before the plants fall and flounce all over.  After that we do the viney melons, squashes, sweet potatoes, etc. before the plants crawl out all over the place and make mulching difficult. Last comes tomatoes, eggplants and peppers which especially need to be growing vigorously in warm soil before mulching. Do not mulch onions up close. The bulbs need air and sunlight to grow properly. I usually do not mulch the sweet corn either since it is easy to cultivate weeds between the rows with the tiller.

Exceptions to the rule of timing:
I put leaf mulch on the asparagus row as soon as possible after the first spears appear. That will be early, the last week of April here, but obviously the soil is warm enough or the shoots wouldn’t be coming up. Asparagus spears will come right up through the mulch but delay weeds. Then in June, on hands and knees, I crawl along the bed and manually turn over that leaf mulch, at the same time pulling out weeds, especially the zillions of little asparagus seedlings that have started to grow despite the mulch.

I mulch the raspberry patch heavily as soon as the raspberry leaves start coming out. I just throw leaf mulch with a fork over the patch and let them fall helter-skelter among the canes. New canes will come up right through a leaf mulch but most weeds won’t, at least for a month or so.

In a northern climate like ours, strawberries should be mulched in winter after the ground has frozen. Wheat or oat straw is the preferred mulch (rich in potassium). This mulch keeps the ground from thawing and freezing repeatedly over winter, which will heave strawberry plants out of the ground. Winter mulch also delays spring growth, therefore spring blossoming, therefore fewer frost-killed blossoms. Also, mulch protects the berry plants from deer which often take a craving for the first growth in spring. After the plants are pushing hard to get up through the mulch, pull the straw back to the edges of the strawberry bed where it will keep the subsequent berries clean and row middles relatively free of weeds.

Depth of mulch: As a general rule four inches is about right. Fluffier materials can go on thicker but you don’t want more mulch than will decompose over winter. If you grind up the leaves or other mulches as with a lawn mower, they are usually dense enough so that four inches or even three will do the job. Grass clippings, being fine, can work well at three inches. Sawdust will do the job at three inches. The trick is to snuggle the mulches up close to the growing plants where it is hardest to control weeds. Some weeds will still come up close to the plants you are mulching.

Materials for mulching: It is not a good idea to use fresh barn manure close to leafy vegetables to be eaten directly and besides the ammonia nitrogen will wilt the plants. Barn manure bedding from the previous year is fine, and two or three years old is  better.  I like sheep manure bedding, trampled in the barn by the sheep to a hard, dry mass. I peel it up with a manure fork in layers that are only an inch or two thick, but impenetrable to weeds.

Straw, hay, tree leaves and grass clippings are of course all fine. I pile them near the garden for use the next year. I don’t want them to compost much before use. Finished compost will not smother weeds. Half composted materials may not last out the whole growing season before decomposing. Old hay that is full of weeds seeds is not so desirable, but if you watch carefully when the weed seeds germinate, you can turn the hay mulch over thereby killing the weeds. Chopped up cornstalks, bagasse (dried sugarcane pulp), peat moss, cocoa bean hulls and other commercial products are good but comparatively expensive.

Sawdust or wood shavings, after having served as bedding for chickens, or if well rotted, make a very nice mulch, easy to work in and around garden plants. Fresh sawdust or shavings are less desirable but the caution often given, that they will rob nitrogen from the soil, is not true enough to worry about on a good, rich soil. Reason?  Something almost magical takes place in that inch or so of no man’s land between good soil and the layer of decomposing mulch. Scientists tell me that oil microbes run wild there and create nitrogen as fast as the decomposition process is removing it. This process is otherwise called sheet composting and in my experience is just as effective as a soil builder as going through the laborious process of making compost in piles.

Warnings. If you do a lot of mulch gardening, you will have plenty of earthworms (good) but also a plague of moles (bad).  Also mulch does not control all weeds. Thistles will, given a little time, come right up through most organic mulches. Towards the end of the growing season, grasses will creep in from the edge of the lawn. By fall most kinds of weeds will find their way through the mulch but much fewer in number than not mulching.

On the other hand, mulching works very well on our two most bothersome  weeds:  chickweed and purslane. Yes, I know. Both are quite edible. So? After you eat a ton of the stuff, what do you do with the next four tons?
See also Gene’s Organic Garden and Small Farm Skills – Hoemanship
Gene and Carol Logsdon have a small-scale experimental farm in Wyandot County, Ohio.
Gene is author of
The Mother of All Arts: Agrarianism and the Creative Impulse (Culture of the Land),
The Last of the Husbandmen: A Novel of Farming Life, and All Flesh Is Grass: Pleasures & Promises Of Pasture Farming |
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Margaret, black plastic mulch is handy for larger commercial operations and a layer of it will warm up the ground in early spring quite dramatically. But to me it is ugly and I don’t use it anymore. I have enough plant residue mulch of all kinds. Gene

Hi Gene, In your post you refer to black plastic mulch as a subject for another time. I’m eager to hear your thoughts about it, if you get a chance. Thanks!

The above comments most interesting. Growing mulch intrigues me. I wonder if one could just let chickweed grow under and around taller vegetables? I don’t notice many weeds growing up through chickweed and it stays fairly low growing. Would chickweed take too much of the nutrients away from the other vegetables?
Commercial purslane? Ought to be outlawed in my opinion.
Yes, straw bales are going up in price. So is everything else I buy, seems to me. But our dear government says inflation is under control and so it’s all right to print a trillion dollars worth of paper money that has no backing. Next year we may be able to mulch with paper dollars. Gene Logsdon

I like to grow my mulch for some things. A mix of annual rye and red clover works well between my asparagus rows. I like to plant buckwheat between the tomato rows. I snap it off as it grows, around the area of a leaf node on the stem (not that I really look closely when I am grabbing a handful!). Then I lay that handful down around the tomato stem. The buckwheat grows back fast, so it isn’t long before I have a nice thick stand between rows and a healthy layer of drying ones around the plants. Dwarf white clover works well around brassicas and tills up pretty easy the next spring. Chickling vetch is good between bush beans because it dies off over winter (usually!) and you can either till it in or just leave it as a cover mulch and plant through it.

Straw is getting ridiculous in price. $4-$5 a bale last fall! I thought $3 was bad. Seed is cheaper!

I am so enjoying these blogs, Gene. Thanks for taking the time to do it. I keeps me pacified now in between your book writing! 😉

I have found from careful experiments that applying fresh grass cuttings of any sort to soil as a mulch will actually decrease the amount of humus in the soil and cause it to go hard and difficult to sow. I believe the rapidly released sugars from the green grass leach into the soil and encourage the microbes there to feed upon the humus.

Mulching can be useful but I don’t think it is a miracle cure for creating rich soil. I basically use it when I generate it from other activities (slashing/pruning/animal bedding) but I wouldnt go out of my way to buy it and shovel it around. In the subtropics I find green manure crops, slashed in place and allowed to regrow several times, are far more effective at creating healthy soil.

What do you do with the chickweed and purslane – feed it to your chickens of course. I am in Alabama and delay mulching some parts of the garden to LET the chickweed grow along with lambsquarters (which we eat and feed some to the chickens but they much prefer chickweed). I never have enough for our manure producing biddies. Don’t have wild purslane and commercial varieties don’t do well here. Ah well.

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