More about composting - Vermicomposting Introduction Vermicompost (also called worm compost vermicast, worm castings, worm humus or worm manure) is the base-product of the breakdown of natural material by earthworms. Vermicompost is a nutrient-rich, organic fertilizer, and soil conditioner. The process of making vermicompost is called vermicomposting. Vermicompost contains not only worm castings, but also bedding materials and organic wastes at a mixture of stages of decomposition. It also contains worms at different stages of growth and other microorganisms associated with the process. Earthworms’ castings in the home garden usually contain 5 to 10 times more additional nitrogen, phosphorous, and potassium than the adjacent soil. Secretions in the intestinal tracts of the worms, along with soil passing through the worms, make the nutrients needed by plants more concentrated and available for plant uptake.
Vermicomposting can be performed all year-round, providing that environmental conditions are suitable. For improved efficiency, care should be taken to ensure that food given and environmental circumstances allow worms to reproduce productively and tolerate climatic changes. If conditions are appropriate, vermicomposting offers an easy solution to the management of compostable organic wastes. Five Conditions needed for Successful Vermicomposting 1. Living Environment 2. Food Source 3. Moisture 4. Aeration 5. Protection from Temperature Extremes 1. Living Environment or Bedding is any material that provides the worms with a relatively stable habitat. This habitat must have the following characteristics:
- High absorbency. Worms breathe through their skins and therefore must have a moist environment in which to live. If a worm’s skin dries out, it dies. The bedding must be able to absorb and retain water fairly well if the worms are to thrive.
- Good bulking capability. If the material is too dense to begin with, or packs too firmly, then the flow of air is reduced. Worms require oxygen to live, just as we do. Different materials affect the overall porosity of the bedding through a variety of factors, including the range of particle size and shape, the texture, and the strength and rigidity of its structure.
- Low protein and/or nitrogen content (high Carbon: Nitrogen ratio).Although the worms do consume their bedding as it breaks down, it is very important that this be a slow process. High protein/nitrogen levels can result in rapid disrepair and its associated heating, creating harsh, often fatal, conditions. Heating can transpire safely in the food layers of the vermiculture or vermicomposting system, but not in the bedding.
2. Worm Food: Compost worms are big eaters. Under model conditions, they are able to devour in excess of their body weight each day, although general rule is half of their body weight per day. They will eat almost everything organic (that is, of plant or animal origin), but they definitely prefer some foods more than others. Do Feed Worms:
- Vegetable scraps: crop waste
- Tree and bush leaves, and grasses
- Fruit scraps and peels (mold/rot is fine)
- Moldy Bread and grains
- Used Tea leaves
- Non-greasy food leftovers
- Coffee grounds
- Crushed egg shells
- Most moist paper products
- Manures (must pre compost)
- Citrus peels
- Garlic, onion scraps
- Hot spices
- Meats, fish
- Greasy foods
- Dairy products
- Twigs and branches
- Dog/cat feces
3. Moisture Worms breathe through their skins; moisture content in the bedding of less than 50% is dangerous to the creatures. With the exception of extreme heat or cold, nothing will kill worms faster than a lack of adequate moisture. The bedding used must be able to hold sufficient moisture if the worms are to have a livable environment. The ideal moisture-content range for vermicomposting is 70-90%. 4. Aeration Worms are oxygen breathers and cannot live an-aerobically (defined as the absence of oxygen). When factors such as high levels of grease in the feedstock or excessive moisture combined with poor aeration cut off oxygen supplies, areas of the worm bed, or even the entire system, can become anaerobic. This will kill the worms very quickly. Not only are the worms deprived of oxygen, they are also killed by toxic substances (e.g., ammonia) created by different sets of microbes that multiply under these conditions. This is one of the main reasons for not including meat or other greasy wastes in worm feedstock unless they have been pre-composted to break down the oils and fats. 5. Temperature Control Controlling temperature to within the worms’ tolerance is crucial to both vermicomposting and vermiculture processes. This does not mean, however, that heated buildings or cooling systems are required. Compost worms can survive temperatures from between 10◦C and 35◦C but prefer a range in the 20s (◦C). Above 35◦C will cause the worms to leave the area. If they cannot leave, they will quickly die. In general, warmer temperatures (above 20◦C) stimulate reproduction. If you wish to breed the worms (vermiculture), the temperature must stay above 15◦C (minimum). How to make a worm farm (pit method) Prepare pit 2mX1mX1m deep Broken bricks, pebbles and sand - 5cms 15cm layer of loamy soil Sprinkling of fresh cow manure Add 100 earthworms to this vermibed 5cm layer of straw, leaf litter, farm residues Cover with leaves, keeping moist for 1 month, may use chicken wire on the top to keep out mongoose Add 6cm layers of organic wastes every other day, watering until nearly full - turn wastes in After 30 days, heap can be harvested Heap pile in open place, allow worms to reach bottom, remove top layers, dry and sieve for application to crops How to make a worm farm II (bin method) Need a bin of some kind with a drain in the bottom or an old bathtub or large sink. You can also use a large flowerpot with a hole in the bottom Put 2/3 full with manure 1/3 green scraps (lettuce, green veg, cabbage, etc) laid on top (don't mix in) One kilo of worms (they will breed up to the max) -Keep high moisture in the worm bin Cover to keep it dark, cool, damp and no rain coming in, and protection from birds and mongoose. To Harvest Vermicompost made in a bin: -put the food only on one side of the bin, -two days later 95% of worms will be there. -harvest the other side, and use! -add new manure to that side and put the food there (plenty moist) -two days later worms will move into that side. -harvest worm castings (worm poo) -add more manure and kitchen scraps How to Use the Vermicompost and Benefits -use the castings like compost, best on annuals, because of high bacteria count -not so good on trees because low fungus -great for making compost tea (add a little to a bucket of water, add sugar or over ripe fruit and bubble using a fish tank pump and airstones for 48 hours. Strain and water as a fertilizer on plants during growing season. -improvement of soil fertility -improvement of saline (salty) and acidic soils -wasteland, degraded and weak soil development -healthy produce and yield and possible increase of yield from 40% to 100% within four years -saving of irrigation water due to increased water holding capacity of soil. -control of pathogens (disease causing organisms) and termites Worm Juice (Vermiwash): -We can also harvest the worm juice -Very rich material, used for orchids or as a powerful fertilizer -Liquid should be able to drip out of the bottom of the container into a bottle or container -Dilute before using 1:50 with water (200ml of vermiwash with 10 litres of water) before using -Use for watering plants, conditioning soil, add to compost