The Mulch Book




STOREY COMMUNICATIONS               1991


Preface, Charlotte, Vermont Fall, 1973

Mulching first began to appeal to me when I realized that it might save me and my family some work. The nicest thing about mulching is that your children may not have to do so much monotonous work in the garden.

  • The first point of The Mulch Book is that we cannot allow our children to be turned off by gardening.
  • The second point is: After months of studying the intricacies of mulching, the temptation is to think of mulch as a panacea for all gardening ills. It is not. Mulching is just one arrow in the gardener’s quiver.
  • The Mulch Book is only one brief chapter in the tremendous body of scientific information, practical experience, literature, and folklore that would compromise the “Complete Gardening Book” which because of its vast nature can never be fully written.
  • Mulching is like a double-headed axe. It is a useful tool but it can be a dangerous one if not used carefully.
  • In most cases, mulching should be used like an insurance policy, as a way of hedging your bet on the success of your garden. Ideally we should have large enough gardens, all of us, so that we could mulch part of each crop – guarding it against drought, weeds, and heat – and leave the other part without mulch. By not going the whole hog, either way, in any given year, we would all at least come up with something to eat.


Chapter 1: Introduction

The Mulch Book was originally written in the early 1970s, when the interest in vegetable gardening was peaking. At that time, the most celebrated benefit of mulching was that it reduced or eliminated time spent weeding the vegetable garden. While that advantage still holds, mulching has become an even greater factor in the area of water conservation.

Our water supply is finite and often unevenly distributed. Some gardeners may be suffering from water shortages and brush fires, while others may be building levees and raised beds. Although mulches may not do much to control excess moisture, they are essential in the battle against water loss.

They are so important, in fact, that in 1989 a bill was introduced in California that, among other things, required the use of mulches. This bill has often been referred to as the Xeriscape Act of 1989. Before you think I am using dirty words, let me explain. Xeriscaping is a relatively new garden design principle whose aim is to reduce the amount of water used on landscapes. While the idea of conserving water in the garden has been around for some time, the xeriscape concept was refined by the Denver Water Department in 1981, after a particularly dry summer. They developed what have become the seven basic principles of xeriscaping: proper planning and design; limited use of turf areas; use of efficient irrigation systems; soil improvement; mulching; use of plants that demand less water, and appropriate maintenance (weeding, fertilizing, etc.). This concept quickly spread to Florida, Texas, Arizona, and California, where droughts are a fact of life. The National Xeriscaping Council, inc. has also been established in Austin, Texas to coordinate and promote the xeriscaping movement. After all that, who would need to be convinced to use mulches?

It seems though, that mulching does deserve more justification. For one thing, mulch doesn’t even sound very nice, which may be one strike against it to begin with. In its earliest Middle English sense the word ‘mulsh’ was an adjective that meant, according to Mr. Webster, ‘softer or yielding.’ That’s not so bad. But by the time our language had evolved into what is now called Early Modern English centuries later, the ‘s’ in mulsh had become a ‘c,’ the adjective had become a noun, the word itself had come to mean ‘rotten hay,’ and something pleasant was lost in the evolution.

Now this is not to suggest that ‘rotten hay’ is necessarily undesirable nor that rotted hay is the only kind of mulch there is. There are many, many kinds of materials that can be used for mulching, as we shall see. In fact, if you use your imagination a bit you probably can dream up some things to use for mulch that are not mentioned in The Mulch Book. The point is that to the layman the thought of hoarding, handling, and spreading around heaps of old, dark, moldy hay at best is strange, not to say repulsive. To the knowledgeable gardener, on the other hand, mulch can be the most beautiful stuff in the world.

But mulching needs justification among serious and experienced gardeners, too. It is awfully hard to imagine at first glance that a subject like mulching could be very controversial. I mean, either you like to mulch your garden or you don’t, right? Not so. Highly regarded gardening authorities like Ruth Stout, known to many gardeners as the ‘complete mulcher,’ and Leonard Wickenden, a prominent biochemist and thoroughly experienced organic gardener, have carried on a mulching debate in gardening literature for years. Some people don’t know with whom to side, so they don’t bother to mulch. We’ll have a look at each of their points of view a little later on.

Some object to mulching for purely aesthetic reasons. Lots of gardeners prefer the traditional look of arrow-straight rows and bare, immaculately cultivated earth. There are still plenty of these ‘model’ gardens around, and that sort of thing is fine if you have lots time and patience, plenty of water, and maybe a few slave laborers around your house who can help you maintain this kind of elegance. Most of us do not. Let’s face it: except for the very affluent, the days of the full-time hired gardener are gone forever. Besides, mulch does not have to be unattractive, as we shall also see.

Because my garden is here in a northern sector of the country, I know that what works well specifically for me may not necessarily work well for you in your garden. You also should remember that there is no one ‘right’ way and no one ‘wrong’ way to mulch. There are good ways and there are not-so-good ways. This book offers suggestions about some ways to mulch your gardens to make them happier, healthier, and more rewarding. I will also try to make you aware of certain dangers and pitfalls, but I will never say, ‘This is the way.’ That is for you to decide.

Chapter 2: Here’s Why: The Benefits of Mulching

Mulching has many benefits, not the least of which, as far as I’m concerned, is that you can walk around in your garden on rainy days and not have three inches of sticky mud on the soles of your shoes when you come back inside.

  • According to Dr. Rakov, the three major benefits of mulch are: the reduction of water losses from the soil, the suppression of weed growth, and the protection from soil temperature extremes.


Soil moisture retention

  • Moisture evaporation from soil covered with mulch is reduced anywhere from 10% to 50%.


Weed suppression

  • One study has found weeding time to be reduced by almost two-thirds through the use of mulches, but the mulch must be weed-free; be deep enough to prevent existing weeds from germinating; and mulches won’t smother all weeds.


Soil temperature

  • The effect of mulching on soil temperature is probably one of the most often overlooked benefits. Mulch is insulation. It keeps the soil around your plant’s roots cooler during hot days and warmer during cooler nights.
  • It’s those rapid changes in temperature that not only threaten aboveground growth, but may send tender plant roots into shock.
  • Winter mulches are usually applied in the fall, after the plants are dormant, and are removed the following spring.
  • Mulches used to control soil temperature in the summer – ‘growing’ or ‘cultural’ mulches – are applied in the spring and stay in place for the majority of the growing season.
  • The purpose may be to raise the soil temperature – black plastic around tomatoes and peppers. In others, mulch may be applied to keep the soil temperatures down.
  • Extremely high soil temperatures can inhibit root growth and may actually damage some shallow-rooted plants. A mulch can reduce soil temperature by as much as 10 degrees F.


Stabilizes and improves the soil

  • Mulching prevents soil compaction and crusting of the soil surface by absorbing the impact of falling raindrops. Water penetrates through loose, granulated soil but runs off hard, compacted earth. Mulch will control wind and water erosion by slowing water runoff and will help to hold soil in place, even on steep slopes.
  • Mulch can be considered a soil conditioner. Many of the organic mulches, like shredded leaves or bark chips, will add organic matter to your soils as they decompose.
  • Mulching will also encourage earthworms, which further aerate the soil and release nutrients in the form of ‘castings.’ Mulching keeps your soil friable without your having to work at it.
  • Mulch stimulates increased microbial activity in the soil. Certain bacteria are every bit as important as worms. This means, as Ruth Stout suggests, that your garden is operating very much like a compost heap.


Helps you grow healthier plants

  • Mulched plants, especially vegetables, are less diseased and more uniform than those without mulch.
  • Mulching protects ripening vegetables, like tomatoes, melons, pumpkins, and squash, from coming in direct contact with the soil, which means fewer ‘bad’ spots, rotten places, and mold.
  • Mulching helps to reduce plant stress. Healthy, strong plants tend to be bothered less by insects and other pests.


Nutrient availability

  • Organic mulch can contribute to the potassium availability of the soil and can also contribute nitrogen, phosphorus, and several trace elements to the soil chemistry.
  • Dr. Rakow suggests supplementing mulched areas with some other fertilizer source, since the mulch alone may not be enough.


Environmentally sound

  • Using mulches for weed control helps cut down our use and dependence on chemical herbicides and is an excellent way to reduce and recycle yard waste.



  • Many folks mulch just because they like the way it looks.


Chapter 3: To Give the Devils Their Due: Some Drawbacks to Mulching

  • I thought I’d introduce you to a few of the controversies associated with mulching.
  • Ruth Stout, who had a very green thumb and a way with words, wrote three famous gardening books – How to Have a Green Thumb without an Aching Back, Gardening without Work, The No-Work Garden Book.


The Stout system

  • “Make your garden your compost pile. My way is simply to keep a thick mulch of any vegetable matter that rots on both my garden and flower garden all year round. A compost heap is too much trouble. Just spread the mulch where you would have spread the compost anyway. In time it will rot and become rich dirt. For the past twenty-six years I have used no fertilizer of any kind on any part of my garden except rotting mulch and cottonseed meal. I broadcast the latter in the winter at the rate of five pounds to every one hundred square feet of my plot. I’m not really convinced that my soil needs the meal, but I have been told it does for nitrogen. However, if drivers weren’t driving in here quite often to inspect my system, I think I would skip the cottonseed meal for a season and see if it made any difference. But as long as I am exhibiting the excellent results which I get from my method, with so little work, I can’t afford to have a failure.”


The attack

  • Along came Leonard Wickenden, the ‘gardeners organic gardener,’ who didn’t buy Ruth Stout’s act.


The rebuttal

  • Ruth Stout’s rebuttal is characteristically unscientific.


Sorting it out

  • If you are not entirely convinced by Ruth Stout’s rebuttal, let me put in my two cent’s worth.


Problems and solutions

  • By far, the vast majority of my own experiences directly contradict the claims of Mr. Wickenden. I believe that with every problem comes a solution. Let’s look at these one by one.


Can’t do it all

  • It’s true mulches can’t smother every weed.


Creates nitrogen deficiencies

  • Any fresh, light-colored, unweathered organic mulch will steal nitrogen from your plants during the earliest stages of decomposition. Eventually, though, these will add nutrients to the soil as they decompose.


Inhibits water penetration

  • If you decide to use plastics, be sure the ground is moistened first. Make slits or holes in the vicinity of your plants to allow for watering.


Fire hazard

  • Some mulches, like sawdust, are particularly susceptible to spontaneous combustion.


Creates a breeding ground for insects, slugs, and snails

  • The decaying, rich-smelling organic mulches are alive with all sorts of creepy-crawling insect things, most of which aren’t doing any harm. I just leave them to their creeping and crawling.
  • You will find an increase in the slug and snail populations, particularly in years with a wet spring. Pull back the mulch and sprinkle salt or one of the chemical slug controls.
  • A light dusting of wood ashes or diatomaceous earth on the ground at the base of my plants works well.


Blocks air exchange

  • If organic mulches are applied too deeply or repeatedly, they can restrict air movement. Sometimes we add another 4 inches of mulch when we only need 1 inch to freshen the appearance.


Rodents live in mulch

  • Never apply an organic mulch all the way up to the base of your trees or shrubs. Leave a space between the mulch and the plant.


Ugly, unpleasant, and difficult to handle

  • I agree with Mr. Wickenden. Mulching is a matter personal judgment. If you select the wrong mulch for your situation it can be a big head ache. If your mulching repertoire is such that you can choose the right mulch at the right time, you can enhance the attractiveness and productivity of your garden while expending a minimum of effort, time, and money.


Chapter 4: A Few Definitions

Chapter 5: Types of Mulch

  • Here is a rundown on the different types of mulches and how you can benefit from them.


Chapter 6: Tips for Making the Most of Mulch

  • I’ll make specific recommendations for mulching vegetables, fruits, and ornamental plants a little later, but for now let’s start with some general tips for getting the most out of your mulch.


Chapter 7: Here’s How with vegetables

Chapter 8: Here’s How with Fruits

Chapter 9: Here’s How with Ornamentals


  • The most comforting thing about gardening is that no one has all the answers. Any gardener who claims to know it all should be drummed out of the gardening corps – not because he is a know-it-all, but because somewhere along the line he has lost that sense of mystery, that feeling of humble uncertainty that all gardeners should have.
  • The botanical scientists and horticultural experimenters must keep on with their good work. They must continue to give us direction and reduce as much as possible the chances of us failing with our gardens.
  • If this generation, or even the next, has trouble distinguishing between scientific fact and old wives’ remedies that seem to work in the garden, no one should worry about it too much.


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