STONE MULCHING IN THE GARDEN

J. I. RODALE

RODALE PRESS                 1949

PART III

Chapter 3: The Reasons

• A rock mulch does not permit grass or weeds to spring up in its domain, thus competing with your plant or tree for sustenance.
• It does away with the need of either plowing or discing, leaving the bacteria, the earthworms, and other valuable organisms undisturbed.
• It conserves water, an extremely vital point in setting out trees in dry, irrigated regions. The protective stones act as a buffer against the withering effect of the wind. The flowing rains are easily captured by the rocks.
• Softer stones act as a sponge, absorbing dew and moisture, giving it back to the soil slowly.
• A stone mulch causes the earth under it to be well aerated, providing conditions that are ideal for bacteria, earthworms, and burrowing insects.
• Stones furnish a temperature regulating mechanism which is beneficial in the spring and in the fall.
• In hurricane regions the stone mulch should be built much higher in the sections nearest to the trunk to serve as a wind-break.
• Many types of stones disintegrate at the bottom, thus enriching the soil with valuable minerals in a form that is soluble.
• Many rocks are very slightly radioactive and/or possess fluorescent qualities and/or produce halos that may exert a beneficial influence on a growing plant.
• A stone-mulch improves the mycorrhizal association. The mycorrhizae are a fungous growth on the roots of plants and live in a symbiotic or partnership arrangement with their host, the roots.
• When chemical fertilizers are used the mycorrhiza is either absent or, if present, is defective. There is sufficient evidence to prove that the mycorrhizal mechanism is the bridge between the soil and human health, the state of which is obviously contingent on the quality of man’s food which itself stems from the soil.

 

Chapter 4: Letters

·         After my article on stone-mulching in Organic Gardening Magazine, it was hailed by an avalanche of letters. This chapter will comprise a selection of the most noteworthy and informative letters.

·         “The fissured limestone on this mountain top on the island of Majorca leaves almost no earth visible. But wild olives grow in the crannies, send their roots far down into the fissures, look healthy, are grafted to good varieties, and yield well.”

·         “Many efforts to transplant local cedars even a few miles failed, until rocks were placed around the foot, when they grow and flourish amazingly.”

·         “Some of the best peach orchards in the country are on exceedingly stony land; the stones hold heat well and are troublesome only in working the ground.”

• “I have seen sickly groves of limes and other fruits revived when rocks were piled high around the trunk to keep the bark from scorching and the roots from becoming dry and hot.”
• “I covered my pansy bed with two inches of gravel. The unusual rains rotted most of them out but 3 plants lived through a second winter. One of them is enormous with as many as 15 blooms, some as large as 4 inches.”
• “A friend of mine growing roses, digs down two feet and places crushed stone at the bottom to insure good drainage.”
• “I’m sure the reason why your earthworms multiply so well under your rock mulch is because they are protected from birds.”
• “It seems to me that the two worst enemies of successful gardens are evaporation and weeds. Dry gardens and weedy gardens are seldom, if ever, profitable. Rock mulch will deal with these two arch enemies sternly and efficaciously.”
• “I make mulching rocks from furnace ash using cake pans eight inches square and one and one quarter inches deep, coated with machine oil or lined with paper, with one part cement to three parts of ashes.” (I strongly advise against the use of coal ashes as it contains soluble sulphates known to kill worms.)
• “I can report surprisingly good results from rock-mulching some young fruit trees. All in all, I can only highly recommend this sound, natural way of treating our starving soil.”

 

Chapter 5: Farming With Stones

• His father had one field that was littered thick with small stones. He could always reap a bumper crop of rye there, because that particular grain craves a damp soil.
• Open Virgil’s book on Agriculture and you will find a discussion of stone mulching in the vineyard. Columella, palladius, Pliny, and Theophrastus are equally reliable witnesses to the practice of stone mulching.
• Modern scientific farming has much to learn by perusing the literature of the past, and by applying some of the venerable old-time practices in both fertilizer usage and crop growing.
• We have much to learn from China. Yet in the face of this, the United States has sent agricultural missions there in the last few years to teach her how to farm in the Western manner – we who have ruined 51% of our soils in only one century.
• Dr. Lowdermilk, who taught China American methods of fighting erosion says: “About Lanchow we were introduced to pebble mulching as a means of conserving moisture in farmlands. This practice is old. It consists of the heavy task of digging out river gravels and spreading them over fields to a depth of three to four inches. The layer of pebbles causes all the rain to soak into the soil and reduces evaporation loss, thus increasing effectiveness of a scanty rainfall of about 12 inches. The favorite crops for pebble mulch are melons, watermelons, cantaloupes, and cotton.”
• I don’t recommend the broad or indiscriminate application of rock mulches to the farm. This book deals with rock-mulching in the garden and small fruit orchard, but several letters have been received from people who have applied it to a large acreage.
• Seumas Ridge writes: “I often saw an Aran man planting potato slits on the naked rock, and covering them with weed and dabs of clay. Yet, the finest crops in Eire grow there, when the year comes favorable.”

 

Chapter 6: The Stone Vegetable Garden

• I experimented with a combination of Faulkner’s plowless method of gardening and rock mulching.
• There is no question that keeping your best surface top-soil always near the surface has numerous advantages.
• We laid stones in neat rows, the stone sections being about two feet wide and the soil section being eight to ten inches. The only cultivation would be in the rows, which would get a vigorous stirring before each planting.
• Before putting down the stones we applied a generous dressing of compost and built up the level of soil in the rows with soil and compost. We made one serious mistake. We should have given the land one farewell plowing.
• This stone vegetable garden is ideal for Mr. Lazyman, for weeding is pared down to a minimum. One of the principal advantages is the conservation of moisture under the rocks, and for this reason such a garden should be ideal for arid country.
• The stones also precipitate more dew, as well as prevent the hot sun from reaching the roots.
• As an erosion preventative it is ideal. It stops ordinary as well as sheet or wind erosion. In fact such erosion is non-existent. It is ideal for use on steep or inclined land.
• There is an affinity between an earthworm and a rock. Pick up a sizeable rock in a field and your chances of seeing an earthworm or two right on the soil surface is very good.
• The earthworm likes the darkness, moisture and warmth under the rock, but in addition, he actually chews on it.
• In our stone garden there are a dozen kinds of rock. There is a sufficiency in them of practically every kind of mineral needed by the soil.
• Every row and section is numbered so that you can rotate crops year to year.
• The asparagus bed will find a secure home in the rock rows and stay put.
• We started 14 rows of strawberries last fall. Harvesting is marvelously simple. You can control the acidity or alkalinity of each row. When we made our strawberry bed we brought in acid soil from the woods and there will never be an application of lime there. We will dig in from time to time thoroughly decayed acid leaf mould.
• Turnips, parsley and watermelons prefer an acid soil. Our Vegetable Pocket Guide tabulates plants with the lime preferences.
• We had steady rain of three days duration and when it stopped I went into the garden immediately and began weeding. In neighboring gardens they didn’t dare enter for three or four days.
• This method is a great time-saver. You limit your self to working in only eight or nine inches of row.
• It is in the row that you put most of your compost so that as the years pass, it will become extremely rich. The ground there should become a marvelous seedbed for starting plants.
• Sir Albert Howard in his Agricultural Testament explains how he witnessed a condition of infestation of aphids. They were present where the soil was extremely hard but absent where the soil was softer.
• The general beauty seems to be enhanced if one confines oneself to low-growing vegetables.
• When the head of a big system of parks saw the amazing one-year growth of asparagus in the stones, he went home and immediately put out a new bed of asparagus in a rock setting.

 

PART TWO

 

Introduction

• In Part Two will be reproduced a few articles that have appeared in Organic Magazine, written by persons who have applied rock mulches of various kinds.

 

Chapter 7: The Vegetable Rock Garden by Raymond Green

Chapter 8: My Rock Orchard by Robert E. Baum

Chapter 9: Pot-Holers and Rock-Pilers

Chapter 10: Rock Mulch by John C. Gifford

Chapter 11: Increase of Earthworm Activity through Rock Mulching by Herbert Clarence White

• During the past eight months since that article appeared, some very interesting, if not startling results have been observed by this writer, especially with regard to the tremendous increase in the earthworm population and activity under the fruit trees and grape vines where the rock mulches were applied over the heavy leaf mulches.
• My three-inch leaf mulches were disappearing as if by magic. Whereas in the Boysenberry patch it took nine to ten months for the earthworm population to devour the three-inch mulch, under the rock mulches the same amount of leaves vanished completely in only sixty days.
• The conditions created by the presence of these cobblestones, stimulated earthworm activity by at least 500%.
• On average it takes about 15 minutes to remove the rocks, apply the leaf mulch and restore the rocks to their former position on top of the leaf mulch.
• The extra time employed in gathering the raw materials and applying these leaf-and-rock mulches is largely, if not wholly compensated for in saving both the time and effort in the after-care of the orchard.
• First in importance to the California gardener is the saving in irrigation. The problem of weeding is automatically solved; no weeds will grow through the heavy leaf-and-rock mulch.
• The problem of fertilizing the orchard is largely solved, for the earthworms convert the mineral-rich leaf mulches into water soluble plant food and distribute it where the feeder roots can take it up most readily.
• The large earthworm population also cultivates and aerates the soil without the danger of disturbing the tender feeder roots near the surface.
• Last but not least, is the large degree of immunity conferred upon the trees and vines thus treated, with the consequent saving in time and materials for poisonous sprays, as well as expensive spraying equipment, which in many orchards has reached an all-time high.
• The soil thus enriched seems to impart a keeping quality and extra flavor to the fruit, not found in fruit that has been grown in soils that have been poisoned by artificial fertilizers and lethal sprays.
• Sound cell structure in tree and fruit also results in a remarkable ‘resistance’ to virus and fungous diseases, and most remarkable of all – a large degree of freedom from insect pests of every description.
• The crowning achievement in this little experiment came when I discovered up to three inches of pure, black, velvety earthworm castings under my trees that had been rock-mulched. Three inches of castings in only four months!
• I am still a bit breathless over this latest discovery. Twice the results in one-third of the time! That is a 600% gain over the results obtained in my Boysenberry patch, as reported in the June issue.
• As I write these lines I am getting a bit dizzy, for if the statisticians are correct, a single one-inch layer of topsoil over an acre of land will weigh approximately 428,571 pounds. Three inches of earthworm castings over an  equal area will weigh 1,285,713 pounds – nearly 643 tons of topsoil – rich neutral colloidal humus, the finest plant food known to agriculture in only four months!
• The remarkable thing about all this is that these results were obtained without ‘planting’ one domesticated red manure worm, or a single wild grey worm in the soil. They just ‘moved in’ when I provided simple living conditions and good food in the form of elm and oak leaves.
• According to statistics from the Government Experiment Stations, and confirmed by leading scientists, the soil which passes through the bodies of these little animals is somehow miraculously changed in both texture and quality. Minerals ‘hidden’ in the soil, which are unavailable for plant nutrition are suddenly released and made available.
• It has been demonstrated that earthworm castings contain 300% more magnesium, 500% more nitrogen, 700% more available phosphates, and 1100% more potassium than the soil from which they came.
• Worms constitute a perpetual fertilizer factory; and once a large earthworm population is established in the soil, little else need be done to keep the land fertile and in top physical condition.
• As Mr. Oliver reports in his famous earthworm classic: “Most soils are deficient in elements necessary for plant life not because the elements are not present, but because they are unavailable to the plant roots. All the elements are in the soil, but which are hidden and unavailable to the plant roots, are broken down by the earthworm and made available. Man has yet to invent, devise or manufacture any machine, any solid or liquid fertilizer as efficient as the earthworm. In this invertebrate animal, Nature has a perpetual soil builder, a four-in-one creature that acts upon the soil as chemist, triturator, cultivator and distributor of plant food. Few creatures equal the burrowing earthworm as a necessity to better health and greater growth to plant and vegetable life, and therefore, indirectly it is of the utmost importance to man.”
• What a pity that modern (so-called ‘improved’) agricultural methods, through the free use of lethal sprays and poisonous chemical fertilizers result in the wholesale destruction and ruthless slaughter of these beneficient little helpers and friends of mankind.
• It would seem that in following popular agricultural procedures the American farmer and gardener is actually ‘killing the goose that lays the golden egg.’ Henceforth our motto should be, ‘LET THEM LIVE!’
• Should not a ‘Soil Building Program’ in place of an ‘Insect Extermination Program’ be the order of the day in America’s new agriculture?