Raising and Culturing Earthworms
Excerpts from Thomas J. Barrett's Harnessing the Earthworm
(Bruce Humphries: Boston, 1947; copyright unrenewed.)
Part 6: Culture
Starting Earthworm Culture
Intensive propagation for maximum results in soil-building requires large numbers of worms, depending on the amount of land to be used for garden, orchard, or farm. It should be borne in mind and emphasized that intensive use of earthworms bears about the same relation to earthworms as found in nature as a power installation for production of electricity, such as Niagara Falls, Boulder Dam, or Bonneyville Dam, has to the unharnessed water power flowing down a native stream. We use from one thousand to five thousand times the concentrations of breeding earthworms per cubic foot of composted material as would be found in the average natural environment with the native earthworm population.
The small city gardener may have only a few square feet of earth, or possibly just a few potted plants or a window box. Others may have a small kitchen vegetable garden or flower garden. Still others may have a market garden or nursery, and so on up to extensive acreage in orchard, farm, or ranch. Earthworm culture may be engaged in successfully, whether it be for producing fine potting material for a few plants, a small garden, or for acreage of any extent. A start may be made in a one-gallon can or a small box, beginning with a few earthworm eggs (called egg-capsules), or a few worms. The technique is practically the same, regardless of the size of the setup.
In a few words, the way to begin earthworm culture is to provide a culture medium of earthworm food in some kind of container or beda tin can, a small wooden box, a compost heap, or a specially designed culture bedadd a few egg-capsules or worms, and keep the culture thoroughly moist and shaded. Further discussion of earthworm food will come later. We have already covered the subject of food for worms in a general manner. Results obtained will, of course, be commensurate with the care and effort expended. Engaging in earthworm culture is very much like starting in to raise chickens. One can start with a few eggs and increase slowly, or start with a large number of eggs and increase rapidly. For a small yard or garden, a small setup is all that is requiredone or two cans or box cultures. For a greater amount of land, a proportionately greater setup should be made as a beginning. As an example of the rapidity of increase which can be made from a small beginning, one thousand egg-capsules were incubated and hatched out. From this start four lug-box cultures (see illustrations and instructions on box culture) of five hundred worms each were set up. Within one year from the time this setup was made, a total of 55,000 egg-capsules had been harvested from these four boxes. The increase was used to impregnate extensive soil-building culture beds and compost heaps and at the end of the first year vast numbers of the soil-builders were at work and multiplying in many tons of composted soil-building material.
Once the initial beginning is made, with a modest cash investment of from five dollars on up to about twenty-five dollars, the main money-cost involved is the small amount of labor required in taking care of the cultures. The material which is used in providing soil-building food for the worms is the same material which should be incorporated into the soil anyway in building and maintaining the highest state of fertility.
Where too small a beginning is made, one is apt to become discouraged with the slow progress made in building up an adequate number of breeding earthworms to show satisfactory results. Therefore we advise the beginner in earthworm culture to make a sizable start. It requires about as much time to look after a single culture box or bed as it does to take care of a number of boxes. Once the setup is made, the main attention for sixty to ninety days will be to sprinkle the cultures with water about once a week, or often enough to keep them moist while the worms are developing.
In giving instructions for making a beginning and proceeding with perfect confidence in success, we shall not discuss makeshift methods. More labor, the main consideration, is involved in following makeshift methods than will be found necessary in doing the thing right. Let us, therefore, proceed on the principle that "anything worth doing is worth doing well." We wish to emphasize that the methods herein described are not arbitrary, except for certain basic principles. In our research and experimentation over a period of a good many years, we have invented or evolved methods, culture beds, and so on, which have proved successful in our own work, as well as in the work of many others who have taken up earthworm culture and followed the methods we have advised. We further counsel every earthworm culturist to experiment constantly and work out methods of his own. In this way comes progress.
Intensive Earthworm Culture in Boxes
Vegetable Lug Boxes
The simplest and most practical method for beginning earthworm culture is propagation in boxes. Many years' experience in the intensive breeding of earthworms for egg-capsule production has demonstrated that a box of the approximate dimensions of 14 inches wide, 18 inches long, and 6 inches deep is the most favorable size both for convenient and easy handling as well as maximum capsule production in order to develop quickly and maintain a steady supply of earthworm eggs for production of breeding stock and for impregnating extensive culture beds and compost heaps, as well as flower pots, beds, lawns, trees, shrubs, and soil in general.
We have found that the standard vegetable lug box, which has an overall measurement of 14 inches wide, 172 inches long and 6 inches deep, answers all purposes for setting up earthworm culture. Such boxes are usually obtainable at the grocery or market at the very reasonable cost of from three to ten cents each. Lug boxes are light in weight, quite strong and durable, and serve the purpose admirably.
To conserve space, boxes may be stacked in tiers four to ten boxes high. Tiers four or five boxes high are most convenient for easy handling. The tiers should be supported above floor or ground upon a base about six inches high. Such a base support may be made from 2 x 6" timber, stood on edge and properly spaced apart by cleats firmly nailed across the ends. The illustrated plan shows the details of a base support with overall dimensions 46 inches long and 17 1/4 inches wide, designed to support three tiers of boxes. Such a base may be made any length desired, but we have found in practice that in leveling the base it is much easier to adjust a short base in a perfectly level position, especially on uneven ground, than it is to adjust a long base. Also, in shifting a base from one location to another, the short, light base is more convenient to handle.
The purpose of the base support is to provide ventilation and drainage and also to prevent escape of the breeder worms. Breeding boxes set flat upon the ground or floor provide a cool, (lamp spot underneath the box and the worms may congregate or escape under the box and burrow into the ground. Supported on a base above floor or ground, the worms will remain in the boxes where the food and moisture are.
By the use of separators between the boxes (see illustrations), made of 2 x 2" material, 17 1/2 inches long and spaced 13 1/4 inches apart by lath cleats, the watering of cultures is facilitated. A hose nozzle or flat sprinkler head can be inserted between the boxes without disturbing the tiers and the entire tier can thus be watered in one or two minutes. Once the cultures are set up, all the attention they require between harvest timesthree or four weeks apartis watering once or twice a week, depending on the weather and temperature. In hot, dry weather more watering is required than in cool, wet weather. Cultures should be kept thoroughly moist at all times for best results. In watering, a gentle sprinkler stream should be used so that the surface of the culture will not be rudely disturbed by the force of a hard stream or spray. We always use a layer of gunny sack material on top of the culture material in each box. The gunny sacking conserves moisture and prevents drying out; and also acts as a water spreader, insuring even spread of the water and preventing disturbance of the culture material by force of the water.
We have found that plenty of gunny sacks are almost indispensable in earthworm culture. Old potato sacks, sugar sacks, feed sacksin fact, old tow sacks of any kindprovide material for a multitude of purposes. We use them for cover material to protect the cultures from excessive heat and cold, for shade in the form of screens tacked on a lath or other light framework. Their main use, however, is as cover material on the surface of the compost in all boxes and culture beds. Such cover material conserves moisture, keeps the surface of the culture dark and damp, and favors maximum capsule-production. The worms will congregate in great numbers immediately below the damp layer of burlap and this favors rapid breeding. We use a heavy pair of tin snips for cutting the sacks into convenient sizes for regular use. Ordinary scissors may be used, but they are not heavy enough for regular use. With tin snips, we can cut several layers of sacking at a time, thus speeding up the process. We have also discovered that it is much easier to cut wet sacks than dry ones. So we usually soak a number of sacks in a tub of water and cut them to the proper dimensions for future use, according to the size of the culture beds to be covered. In large culture beds, we do not cut the sacks at all. For lug-box cultures one sack will provide for four boxes, the edges of the squares being folded over at the sides and ends of boxes.
Properly prepared culture boxes will last from two to four years. Therefore an expenditure of time, plus a few cents' cost in material, is fully justified. Also we have found that there is much greater "living satisfaction" to be derived from things well-done over that derived from careless work. Boxes of the proper dimensions may be made, the size not being arbitrary so long as the depth is kept at about six inches. In intensive propagation for capsule production the depth is important. Earthworms breed at the surface for the most part; so in shallow box cultures they quickly congregate on the surface under the damp burlap cover.
If vegetable lug boxes are used, select good boxes without large knot holes. For drainage bore six to eight quarter-inch holes, properly spaced over bottom of box. The cracks in bottom provide additional drainage. Reinforce bottom of box by nailing a lath cleat across it at each end, thus preventing the thin boards from splitting off around the nail-heads. For each box, cut ten pieces of plasterer's lath, thirteen inches long, to be placed crosswise in bottom of box. This distributes the weight of the wet compost evenly over bottom of box, provides drainage, and prevents sagging of the bottom boards. Also when contents of box are dumped, the crosswise lath prevents the wet compost from adhering to bottom. The lath may be used over and over, the same as the box. For convenient handling, a small strip of lath, six inches long, should be tacked on each end of box, near upper edge, so that the box can be firmly grasped in lifting. In the illustrations, we show a photograph of a lug-box setup, with line-drawings to show the details described above. We suggest very careful study and attention to details.
We usually speak of earthworm food as "compost." While the compost may be thoroughly mixed in any convenient way, on a bare spot of ground, in a box or other container, we have found a mixing box, similar to a cement-mixing trough, a very convenient and practical thing to have on hand. Such a mixing box should be about twelve inches deep, three feet wide, and five to six feet long, with smooth wood or metal bottom and sloping ends. A metal bottom, supported by wood, is preferred, as this makes a practically waterproof box and there is no waste of water while mixing compost. Three cubic feet of material can be conveniently mixed in such a box. Any surplus material not used can be stored in the box and kept moist for future use. The rotting of the material thus stored increases its value as earthworm food. The compost can be mixed with a rake, hoe, or shovel, in the same manner that cement is mixed. It is well to screen the earth first in order to remove small stones or hard clods, using a half inch mesh screen, or even as fine a screen as quarter-inch mesh. The sloping ends of the mixing box facilitate the mixing and emptying of the box. Compost for lug boxes should be very thoroughly broken up by chopping, raking, or screening, similar to the preparation of fine potting material. The finer the better. It should be borne in mind that earthworms have no teeth and that they can swallow particles no larger than the mouth opening.
While the preliminary mixing should be made with practically dry material, it can be lightly sprinkled to lay the flying dust. As the material becomes well broken up, it should be sprinkled more and more, so that when it is ready for use it will be a crumbly mass, damp through and through, but not muddy or "soggy" wet. Compost should not be "flooded," as this tends to "puddle" the fine soil and make a dense mass instead of a crumbly, loamy compost. A good plan is to mix a tray of compost as outlined and then sprinkle it daily for two or three days, turning it thoroughly at each sprinkling. In this way the material will absorb the water evenly through and through. For lug box propagation, too much care cannot be exercised in the preparation of material for capsule production.
For lug-box culture, a fine compost may be prepared of one part manure, one part screened topsoil, and one part agricultural peat moss. A mixture of manures may be used. However, we prefer a mixture of horse and rabbit manure, half-and-half, finely broken up, or a mixture made from rabbit manure only. In considering the kind of manure to use, the available source of manure must be taken into account. For large compost beds, where from a cubic yard to several tons of material is composted, all kinds of manures and vegetable waste, including garbage, can be used to advantage; but for intensive production of capsules in lug boxes, it is highly desirable to have a very fine compost of crumbly material that is not too disagreeable or messy to handle with the bare hands or with gloves. In addition to the material as outlined, we usually work into the compost a liberal sprinkling of some standard, all-purpose chicken mash or corn meal. Corn meal has been found to favor the formation of egg-capsules. If mash is used, the proportion should be about one-half to one pound for each cubic foot of finished compost. If corn meal is used, about one-half pound for each cubic foot of finished compost is sufficient. The mash or corn meal insures a ration of carbohydrates, proteins, and fats for the worms, so that they will be well-nourished, regardless of the organic composition of the composted soil-building material. Maximum production in box culture is dependent on plenty of food. The mash or corn meal should be added before the compost has been wet, so that it can be uniformly distributed throughout the mixture.
Measuring and Quality of Materials
In preparing compost for box culture, we usually mix about three cubic feet of material, which is about all the mixing box will accommodate. An apple box is a handy measure, as it holds approximately a cubic foot. It is not necessary to bother with too fine a measure, as the proportions as outlined are approximate only. So we take an apple box, or other measure, of manure; one box of good loamy topsoil and one box of agricultural peat moss, plus three pounds of chicken mash, or one and one-half pounds of corn meal. The peat may be soaked ahead of time, broken up, and squeezed out. It requires several hours' time fully to impregnate peat with water. We usually soak it twenty-four hours before mixing the compost and then squeeze the surplus water out. Materials should be measured dry, as they bulk up after water is added. Peat moss is best for lug-box culture, as the idea is to provide a compost that will retain a high water content without being soggy or muddy. For large compost beds, straw, hay, leaves, or other vegetable matter may be substituted for peat. Lug-box culture is used particularly for production of large numbers of egg-capsules for impregnation of more extensive compost beds and soil areas. Therefore greater care may be taken and a small additional expense incurred. Commercially, egg-capsules are valued at one cent each, the value being based on labor cost for production and handling. We value a lug-box culture of five hundred breeder worms at fifteen dollars. However, in production for use in impregnating soil, millions of capsules can be propagated at practically no cost other than the cost of the cheap and abundant material used for earthworm food. The parent materials of topsoil used in earthworm culture are the identical materials which should be added to the soil anyway to rebuild and maintain fertile and productive land. The utilization of earthworms in transforming the culture material is the most rapid and efficient method and also produces better soil than any other method.
Loading Culture Boxes with Earthworms
A layer of alfalfa hay about one inch deep should be placed in bottom of the culture box; or two or three thicknesses of old potato sack material (or other gunny sacking) can be used instead of the hay. The hay or burlap improves drainage, prevents compost from adhering to bottom of box, and is favored by the earthworms as food. Then fill box about two-thirds full of the prepared compost. Five hundred breeder earthworms should be placed on top of the compost. If the worms have been received in a shipping container, they will be mixed with prepared earthworm food. The entire contents of the container can be dumped into the prepared box, raked lightly over the surface of the compost, and may be covered with a few additional handfuls of compost. While the compost should not be packed, it is well to smooth and "firm" the surface before adding the worms. A handy tool for this purpose is a plasterer's metal trowel, or a cement finisher's wooden float. A triangular block of wood will answer the purpose. The worms will quickly work down into the compost, making their own burrows. After the worms are added, cover the surface with one or two thicknesses of burlap, which should be well soaked before using. We have already discussed the uses of burlap. We usually cut an old gunny sack into four to eight pieces, approximately the size of the top of box. If the sacking is larger than the box, the edges may be folded over inside the box. This burlap cover does not need to be disturbed until the culture is ready for servicing. The cultures are sprinkled from time to time through this covering, which acts as a spreader for the water and prevents the water from disturbing the surface of the culture. As the burlap rots and disintegrates, it becomes food for the worms and a fresh cover is added as necessary. Experience has proved that such a cover conserves the moisture and prevents the surface from drying out, provdes a dark surface, and favors capsule production.
Impregnating Culture Boxes with Egg-Capsules
The culture boxes for capsules are prepared the same as for breeder worms, as described in the preceding paragraph. Spread two or three hundred earthworm egg-capsules over the surface of the compost and cover with one inch of additional compost. Cover with damp burlap, exactly as outlined for breeder worms. Place in a warm place for incubating and hatching. A temperature of from fifty to seventy degrees in the shade is warm enough. A shed, basement, or other shady place can be utilized. At the proper temperature, the eggs will incubate and hatch in from fourteen to twenty-one days. The newly spawned worms will develop quite rapidly in a warm environment and will reach the reproductive stage in from sixty to ninety days. The culture should not be disturbed during development, except for the necessary watering. Contents of the culture box should be kept moist at all times. After sixty days, the culture may be examined to determine if capsules are being produced. After capsule production is started, the cultures are handled the same as the culture boxes of mature worms. A lug box of compost as described above has sufficient food to develop one to two thousand worms from capsule to reproductive stage. Thus, a thousand or more egg-capsules may be used in a single box, incubated and hatched out and developed over a period of from sixty to ninety days. Then the culture can be divided into two or more boxes. Through experience we have found that about five hundred mature worms to a lug box give the best results in capsule production. If there are too many breeders, they may slow down in reproduction. Although earthworms begin to produce capsules while they are quite small, the fully mature worms will be the best breeders as a rule. Worms live to a great age, unless accidentally destroyed, provided they are in a favorable environment.
If worms are to multiply rapidly, they must have plenty of water. The compost should be kept moist through and through, but not soggy wet. The boxes should be watered with a sprinkler hose, sprinkling can, or hose nozzle once or twice a week, according to what is necessary to keep the cultures moist. Proper state of moisture must be determined by inspection until experience shows correct routine and time for watering. The point of prime importance is never to allow the cultures to "dry out." Preliminary to harvesting the increase, the culture boxes may be allowed to become somewhat dry for a few days, so that the material can be handled without trouble. Wet, muddy compost is not so easily handled as is a moist, crumbly material. Many small details of production and handling will be taught by experiencein fact, that is the only way that they can be learned.
Harvesting the IncreaseProper Work Tables
A table twenty-eight inches high, thirty inches wide, of any desired length, is a convenient size for harvesting operations. It is well to have a railing on back and ends of table, about three inches high, to prevent material from being pushed off the table. The table-top should be smooth, preferably covered with metal, and without cracks. Dump contents of a culture box on table and rake the material into a cone-shaped pile. The material which adheres to sides and bottom of box can be carefully scraped out with a small trowel, old caseknife, putty knife, or spatula. Never use a sharp cutting tool in handling earthworms. While they will stand considerable handling, they should not be cut or injured. If there are a number of boxes to be serviced, a long table can be used and several boxes dumped at one time. During the harvesting, the work table should be in a lighted place, either mild sunshine or under electric light. Worms are very sensitive to light and will quickly burrow down toward the bottom and center of the compost in trying to escape from the light. Have the same number of culture boxes prepared as have been dumped. The old boxes which have been dumped should be prepared again, the same as the original culture boxes. The old boxes will have the original labels on them and can be used for the breeder worms over and over.
After waiting a few minutes after dumping, to allow the worms to work down away from the surface, start the harvesting operation by raking the material from the surface of the cone-shaped pile. Proceed lightly, with the fingers, so as not to injure the worms. An inch or more of material can usually be removed at first; the material removed contains the egg-capsules and is placed in the new culture box; wait a few minutes, to allow the worms to work deeper, then repeat the operation; and so on, until two-thirds or more of the old culture material has been transferred to the new box. Any worms encountered should be transferred back to the old culture box. Experience will soon teach how to harvest the increase as rapidly as possible. In following this routine, the breeder worms will be found in the one-third of the old compost remaining on the table. Most of the egg-capsules will have been transferred to the new culture boxes. The harvested material will contain the capsules which have been produced during the two or three weeks preceding the harvest. Also it will contain a good many young worms. We sometimes wait a day or more, after dumping the culture boxes on the work table, before beginning the harvesting. By waiting a considerable length of time, we shall find that most of the worms will have worked down to the bottom of the pile, and we shall thus be able quickly to transfer the top two-thirds or more to the new culture boxes without encountering any worms and without further waiting.
The remainder of the old compost, with the breeder worms, should now be returned to the old culture boxes, the boxes filled with the new compost and prepared as at the original start. The newly loaded boxes with capsules should be properly marked and a new tier of boxes started. These new cultures will require from sixty to ninety days before they are ready for harvesting operations.
With mature, breeding earthworms, harvesting is carried out every twenty-one to thirty days. Incubation period of capsules is fourteen to twenty-one days, depending on moisture, temperature, and other conditions. Therefore, if harvesting is carried out every twenty-one to thirty days, practically all the increase in capsules will be transferred to new culture boxes, to build up additional breeding stock.
Any system of marking can be followed by the individual as may suit his own inclination. We usually number and date the boxes, maintaining two series of numbers. One series of numbers is for the mature breeder-earthworms. The other series is for the cultures which are developing from egg-capsules. As the new cultures reach the reproductive age, they are transferred to the breeder series. In setting up new breeder boxes, it is well to actually count the worms, allowing five hundred to six hundred per box. It is impossible to recover all the egg-capsules at harvest time and this residue of capsules will hatch out and develop with the mature breeders. In time, the culture boxes will become overpopulated. For this reason, the breeder boxes should be worked over from time to time, and the number of worms reduced to from five hundred to six hundred per box. As previously stated, if a culture box becomes too crowded, the worms will quit producing capsules. They tend to limit their population to correspond to the available food present. We have found that we secure the maximum number of capsules from boxes of between five hundred and six hundred worms each. On the other hand, while the capsules are hatching out and developing, it is all right to have from one thousand to two thousand worms to the box. As they reach the reproductive stage, they can be separated and breeding cultures of the correct number set up. In marking boxes, we have found it convenient to tack a small square of white cardboard to the end of the box, leaving the head of the carpet tack not quite down. Numbers can be typed on card before attaching to box, or can be marked with lead pencil or waterproof pencil after they are tacked on. New cards can be provided as the old cards become ragged. By leaving the head of the carpet tack slightly protruding, we can readily pry it out for attaching new cards from time to time.
Building Large Compost Beds
Once an adequate number of lug-box cultures of mature breeders have been established, all harvested material can be used for impregnating large compost beds for soil-building and for rapid propagation of vast numbers of earthworms. Or the increase can be used directly for impregnating potted plants, flower beds, lawns, gardens, shrubs, trees, or orchards. For instance, in orcharding, a setup of a hundred lug boxes of five hundred breeders each, properly handled, would produce enough increase to impregnate from one hundred to three hundred trees per month. In impregnating orchards, or other trees or shrubs, the harvested, capsule-bearing material is buried around the trees, well back from the bole, with a cover of prepared compost as a mulch, to conserve moisture and furnish an abundance of available food for the developing worms. Once earthworms are established in the soil, they will take care of themselves. Whereever there is sufficient moisture to maintain good vegetation, the earthworms can survive.
Under favorable conditions, which means abundant food and moisture, with temperatures ranging from fifty to seventy or eighty degrees in the shade, earthworms increase with almost incredible rapidity. Mature worms will produce an egg-capsule every seven to ten days. The capsules will incubate and hatch in fourteen to twenty-one days, each egg-capsule producing from one to as high as twenty tiny worms. The newly hatched worms develop rapidly and in sixty to ninety days will begin to produce capsules. We give here a brief summary of two reports, received by the author, which will indicate what can be accomplished from a small beginning. In our own experiments we have verified these results many times.
Report No. 1: From San Bernardino, California. An earthworm culturist wrote that he started a lug-box culture on July 1939, with one hundred earthworm egg-capsules. The pertinent part of this man's letter follows: "On September 24, just two months after I first "planted' the capsules, I dumped the contents of the lug on the sorting table. After carefully sorting over approximately two-thirds of the lug's contents, I had harvested eight hundred egg-capsules and approximately three hundred earthworms. I obtained another lug box, prepared new compost of the same composition as previously described, and divided my crop into the two lugs. The approximate one-third balance of the unsorted original compost was buried under some ferns in front of my house. Judging from the number of egg-capsules I recovered, eight hundred by actual count, from approximately two-thirds of the original compost, I believe it is conservative to estimate that there were at least one thousand egg-capsules in the entire contents of the original lug. It is my plan to take another census of these two lugs on November and following that count, I will inform you of my findings. . . . Roy S. M."
Report No. 2: From Kansas City, Missouri. From a long letter, giving many details of his work in earthworm culture, this Missouri man concludes with this summary: "I closed my year October 1. From June 4, 1943, starting with 1000 capsules, till September 30, 1944, I have produced 55,000 capsules... H. A. H." This man has used his increase in establishing extensive soil-building compost beds and states that he now has vast quantities of the soil-builders at work in these beds, multiplying into almost astronomical numbers, while at the same time breaking down the material into highly fertile top-dressing for his garden acreage.
We have on file many reports similar to the above, fully verifying our own findings over a period of several years' experimental research in practical earthworm culture and soil-building.
Shade, Temperature, Darkness, Moisture
For intensive capsule production in box cultures, temperatures ranging from sixty to eighty degrees will be found most favorable. Drying out quickly affects worms and will inhibit or stop reproduction. Boxes should be kept fairly dark, as earthworms work in darkness. We usually provide covers for the tiers of boxes, made of old gunny sacks, or other cheap material. Worms prefer to work near the surface. Therefore we keep the surface of the culture covered with damp burlap as previously outlined, to conserve moisture and provide darkness on surface of compost. Worms were originally water animals. For intensive production, they still require plenty of water. Cultures should always be moist through and through, though not soggy wet. This point cannot be too strongly emphasized. Boxes should not be flooded. Good drainage should be maintained in bottom of box, so that surplus water will quickly drain out. If cultures are maintained in outdoor shade, the tiers should be protected from flooding rains. Sheds, outhouses, basements, lathhouses, tree shade or other shade will prove satisfactory for earthworm culture setups.
Culture boxes should not be placed flat on the ground or other surface, for in such cases the worms will gradually work out into the ground or gather under the damp bottom. Therefore, as previously outlined, a support for the tiers of boxes should be made of 2 x 6" (two pieces) material, stood on edge 13 3/4 inches apart, with cleats across ends to hold them firmly. Any length base support can be provided, according to the number of tiers that are to be placed on the base. We favor a base support to accommodate three tiers, as this size support is easily handled. The tiers are thus supported six inches above the ground. (For details of construction, see illustrations and line drawings.)
Setup of Earthworm Breeding Boxes
We have given detailed drawings for box culture, with descriptive instructions elsewhere. The illustration opposite page 122 shows an actual photograph of two tiers of lug boxes resting on base. Points to note particularly are: separators between boxes, to allow insertion of hose sprinkler head for watering; burlap sacks resting between boxes on top of separators, for shade and conservation of moisture; structure of separator; small lath hand-hold on ends of boxes; lath strips for placing crosswise in bottom of boxes; structure of base support for the tiers. A convenient size base will support three tiers. Tiers may be any height, four to six boxes being best for handling. While the illustration shows tiers without cover, in actual use we cover the stacks with burlap sacks to keep cultures dark and to conserve moisture.
In a setup of this kind we use approximately 500 breeders to the box. We often harvest upwards of 2,000 egg-capsules per month from each box. We use the increase for impregnating large compost breeding beds, flower beds, lawns, or other land. From this it will be seen that a setup of from five to ten culture boxes will quickly develop vast numbers of worms.
Utility Earthworm Culture Bed
Soil-Building Culture Beds
In our methods for developing earthworm culture, we use lug-box setup for rapid production of earthworm eggs, harvest the eggs from the boxes once every thirty days, and use the increase to impregnate large compost beds for soil-building and for development of vast numbers of earthworms. In harvesting the increase from the culture boxes, it is not necessary to complete the work on a particular date. The incubation period of the egg-capsules is from fourteen to twenty-one days; therefore, if the harvesting operations are carried out every twenty-one to thirty days, practically all the increase is recovered.
We present two designs for large compost culture bedsthe first design illustrated in the four detailed drawings on the next page and the more complicated design illustrated by pictures and detailed construction plans of the "Earthmaster" culture bed which is shown in following pages. The plan with posts set in the ground is the simplest and most practical for the average earthworm farmer.
In the knockdown construction, the size of the bed may be varied larger or smaller as desired by the particular individual, to suit the available space and the extent of the land to be eventually impregnated. The important point to note is the way the 2 x 4" posts are spaced to make the interlocking corners. As will be seen from the pictures, the bed is constructed of 2 x 4" posts and 1 x 6" planking. No nails are used. The side members of the bed, beginning at bottom, are set in place one at a time, followed by the end member, which interlocks between to hold the side member in place. Pressure of the compost material keeps all members in place. The compost is built up layer by layer.
In composting with earthworms, good drainage is of prime importance. To accomplish this, we place on the ground as bottom of the bed a layer of four to six inches of coarse sand or gravel, evenly spread, and on top of this we place a layer of 1 x 6" boards, spaced apart about one-half to one inch. This makes the bed mole and gopher proof. Also one main purpose of the bottom boards is to allow unloading of the finished compost with a shovel, without digging into the sand layer which is placed there for permanent drainage. In unloading the broken-down compost, the end members of this culture bed may be pried out one at a time, thus exposing one open end of the bed and allowing the shoveling of the contents of bed into wheelbarrow or other carrying device for distribution to flower beds, lawn, or other place of final disposition.
While the width and length of the bed may be varied, larger or smaller, as desired, the depth should be maintained at about twenty-four inches. Earthworms are air-breathing animals and must have plenty of air for best results. A depth of about two feet allows for good aeration at all times. Also, in watering a culture bed of this depth it is not difficult to keep the entire contents of the bed thoroughly moist from top to bottom. This is very important in securing best results in earthworm culture. Originally earthworms were water animals and their bodies have a very high water content. Any lack of water slows down their activity and reduces productivity of capsules. Beds should not be flooded, but contents should be kept thoroughly moist though not "soggy" wet. Experience will soon teach how to maintain the best degree of moisture.
In the detailed construction plan we have not shown any cover. A suitable cover, in easily removable sections, should be provided to protect contents of bed from flooding rains and to provide shade and darkness. Worms work best in shade and darkness. Rain water is very fine for the worms, so long as contents of bed are not flooded. If a good shade tree is conveniently located, the bed can be placed, preferably, on north side of tree. This keeps the culture bed as cool as possible during the hot summer months. Worms should not be exposed to hot sunshine directly. However, they are the most active when kept at summer temperatures of from sixty to eighty degrees. In warm earth the greatest production of capsules will be had.
For moisture conservation and to prevent surface drying out, we always use on top of the compost surface a layer of old tow sacks or burlap. Old feed bags, potato sacks, or other porous material can be used. The bed can be watered through this cover material without disturbing the surface of the compost. The cover material acts as a water-break and spreader, so that, in watering with a hose or sprinkler head, the worms and surface of compost are not disturbed by force of the water stream. It is always best to use a sprinkler head on the garden hose, as this distributes the water to better advantage, without flooding.
Garbage Disposal and Waste Utilization
All kitchen waste (garbage) is perfect earthworm food and may be disposed of as it accumulates, spreading it on the compost layer by layer. We always spread the garbage evenly over surface of bed and then add a thin layer of sifted topsoil on top of garbage to absorb odors and furnish a base of soil for combining with the vegetable and other matter. The worms consume and combine everything, the final product being rich, black topsoil for potting or other use. Lawn clippings, leaves, small prunings, all trimmings from the vegetable gardens, such as cabbage leaves, lettuce, or other organic material, can be used in the compost, adding it layer by layer and mixing in enough topsoil or subsoil to prevent heating. In composting with earthworms, it is highly important to mix the compost with enough earth so that a high degree of heat will not be developed. This is also one of the main reasons for keeping the culture bed shallow in depth. Deep piles of compost should be avoided, as they may develop intense heat in the deeper layers, enough to destroy animal life, a fact that should always be borne in mind. A liberal amount of manure mixed into compost is a very great advantage.
Intensive Production of Earthworms
Where a rich compost is provided, a culture bed eight feet long, four feet wide and two feet deep will easily support a population of fifty thousand domesticated earthworms. Once such a culture bed is fully impregnated and developed from a lug-box setup, it is no problem further to develop earthworm culture. In starting additional culture beds, or establishing large compost beds in the open, we simply take a liberal portion of compost from the old culture beda wheelbarrow load or morewith such worms and capsules as it may containand use this as a starter for the new composting operation. This start will quickly impregnate the new compost, and by the time the bed is full there will be an adequate worm population to break it down quickly into fertile topsoil.
We wish to emphasize at this point that we are laying down certain general principles for earthworm culture. We offer definite plans for culture boxes, culture beds, and so on. However, each earthworm culturist should experiment and develop plans of his own. Any kind of box, container, or culture bed will serve, provided that it has good drainage and is kept shaded and moist. The plans we have set forth have been found, through long experience, to be good. By following a successful plan that has already been tested, the beginner will avoid many mistakes. On the other hand, if no experimenting is carried out, new and better methods will not be discovered.