Thousands of tons of foods are being wasted everyday throughout the world and due to their improper management, they are creating further trouble polluting the environment. Though wasting food is not a matter to be happy with; but if it cannot be stopped at least the wastes can be managed in some beneficial ways. Vermicomposting is the process which will protect the environment from the pollution of food scraps, kitchen wastes and other organic wastes in one hand and will give you a great organic fertilizer and healthy crop production on the other.
Vermicomposting and Vermicompost
Latin word ‘Vermi’ means worm; thus ‘Vermicomposting’ refers to composting with worms. In vermicomposting, various organic waste materials are broken down by using worms, bacteria, and fungi. These organisms are nature’s vitally useful tools to decompose organic materials. So, vermicomposting is a process that boosts up nature’s process of decomposing organic waste materials and produces a very useful end product.
Vermicompost, the end product of vermicomposting process, is a heterogeneous mixture of decomposed organic wastes, bedding materials, worm castings, decomposed worms as well as other decomposer organisms, worm cocoons etc. The worm castings, one of the major components of vermicompost, contain lower levels of contaminants and higher levels of nutrients than the organic wastes do before vermicomposting. Vermicompost is rich in many water-soluble nutrients which makes it an excellent organic fertilizer.
Plant Nutrition with Vermicompost
In optimum conditions worms consume huge amount of organic wastes in a day, as much as their own weight at least. After consumption, they take their nourishment from the micro-organisms residing in the wastes; and when they excrete their casts contain an increased number of micro-organisms. Actually their casts contain nearly eight times more micro-organisms, all of them are beneficial and highly favorable to great plant nutrition, than their feed do before consumption. An excellent character of worm casts is that-it is free from all harmful pathogens, because the pathogenic bacteria in their food materials get killed in their gut. Containing huge amount of major plant nutrients, e.g. five-time more N, eleven-time more K and seven-time more P than general soils do, worm casts act as a great nutrient supplier to plants.
Other Benefits of Vermicomposting
Apart from its enormous nutrient supplying capacity, vermicompost has the following other benefits-
• Through earthworms organic waste materials are broken down and produce stable, nontoxic and nutrient-rich material which can be used as an excellent soil conditioner.
• Vermicomposting decreases heavy-metal availability.
• Vermicompost accelerates plants growth with the auxins (hormone like compounds) it contains.
• Vermicompost is observed to give higher germination rate compared to compost.
• Vermicomposting is an aerobic process and therefore it leads to N mineralization. In this process, the earthworms accelerate N mineralization rate.
• Vermicompost decreases fulvic acid carbon and increases humic acid carbon.
• Vermicomposts have slightly lower pH value and slightly higher nutrient concentrations than those of composts.
• Vermicomposts are capable of correcting the undetermined deficiencies plants might have.
• It is very efficient in ameliorating soil physical conditions.
Earthworms for Vermicomposting
Redworms or red wigglers (Lumbricus rubellus) and brandling worms (Eisenia foetida) are two most widely used earthworms for vermicomposting. These earthworms are generally found in aged manure piles, as they prefer the compost or manure environment to ordinary soil. Redworms and brandling worms usually have alternating red and buff-colored stripes; they should not be confused with ordinary field or garden earthworms. Common field or garden earthworms prefer ordinary soil to compost pile.
Making a Worm Box
Worm boxes or worm bins can be bought or made. Can-O-Worms, Worm-a-way, Worm Factory, Worm-A-Roo, Tiger Wormery, Eliminator etc. are some specialized worm containing units available to buy. The commercially available worm boxes are generally made of plastic; if you want to avoid plastic it is better to make wooden one yourself.
Bedding materials should be high in cellulose because they help the worms to breathe. Any inert, fluffy, non-toxic material with enough moisture content can be used as bedding materials. Materials those decompose too rapidly and get hot when moistened should be avoided. A heterogeneous mixture of various bedding materials is a better nutrient supplier. Shredded leaves, dead plants, straw, hay, sawdust, shredded newspapers (non-glossy), cardboard, peat moss, compost, aged manure etc. can be used as useful bedding materials. The worm bin should be filled up to its three-quarters with moist bedding. To create air space to facilitate the worms breathing and to control odors the bedding should be lifted afterwards.
Adding the Worms
Suitable worms for composting can be purchased from worm farms and added to worm boxes afterwards. Redworms can eat their own weight in organic wastes and bedding materials in 24 hours if they get the optimum conditions. Though, in average 2 pounds of earthworms recycle a pound of food waste in a day. The worms are added to the top of the moist bedding; they disappear into the bedding soon after they added.
Adding Food Wastes
All types of food and organic wastes like-vegetable and fruit wastes, pulverized egg shells, coffee grounds, grass clippings, tea bags, manure, and sewage sludge can be used to feed the worms. Using dairy products, meats and bones as feed may bring pests, so they should be avoided. Garlic, onions and spicy foods are not good choices as food material. Chemicals, metals, glass, pet manures, plastics, soaps, poisonous plants and plant parts sprayed with insecticides etc. can destroy the vermicomposting system if added to worm bin.
Maintaining Favorable Temperature and Moisture
Though, redworms are capable of surviving a temperature range of 40-80°F, they require an optimum temperature (55-77°F) to process the food waste and reproduce. If the bin is placed outside, that should be insulated with straw in the winter to protect the worms from freezing. The materials in the bin should be kept moist but soaking must be avoided. The bin must be protected from runoff in the rainy season and drying out in hot summer weather.
Things to be Careful with
Food scraps should be added regularly to the bin for 2-3 months. Overloading the bin with food scraps causes foul odors; stop adding wastes to the bin as soon as it emits odor and resume it when the worms has eaten the excess wastes. Odors may be emitted due to overly moist wastes and bedding materials. To avoid this fluffing up the bedding and checking the drainage holes are useful. The food wastes should be covered properly with straw or moist burlap to keep fruit flies, house flies and other pests away from it. Earthworm-mite may emerge and cause the earthworms stop eating due to overly wet beds.
Harvesting or separating the worms from the finished compost can be done by the following ways-
Earthworms immediately burrow beneath the surface if they are under light, as they are light-sensitive. In this method the finished materials are dumped from the box onto a large piece of plastic on the floor under a 100W light, or outside under the sun. Under light the worms immediately burrow deeper into the compost and the upper compost layer left by the worms are collected. Once the upper layer is removed, the worms burrow further deeper and the surface layer is removed again. Thus eventually a squirming mass of worms are left in which all the worms are trying to hide under each other to avoid light.
In this method all the materials in the box are shifted to one side while the other side of the box is filled with fresh bedding. All the food scraps are added only to the fresh bedding. After a week or two all the earthworms will be found migrated to the fresh bedding. The finished compost left by the worms can be collected easily then.
In this method a piece of nylon or mesh window screening is laid flat on the surface of vermicompost. Then the bin is filled up with fresh bedding on the top of the screen. Waste materials are added regularly to the upper fresh bedding. With the running out of food the worms will migrate to upper new bedding through the screen.
Once the compost is ready that should be applied to soil wisely to ensure maximum benefit from that. Vermicompost should be applied to soil in the following ways-
• Vermicompost can be placed into the topsoil around the plants, like compost application
• In general, vermicompost is two times more effective compared to compost, therefore using half as much of it will do.
• In case of pots and containers about 25% of the growing mixture should be applied rather than applying pure vermicompost.
• ‘Compost tea’ can be prepared by mixing two tablespoons of vermicompost with a liter of water and keeping that for a day with occasional shaking. Once the compost tea, a nutrient-rich liquid fertilizer, is prepared, that can be sprinkled under the plants.
• In cases of transplanting and bare-root transplanting, an even more dilute solution of the ‘compost tea’ can be sprayed on them or they can be placed in the solution for some time.
• To get a good result the vermicompost must be protected from losing its moisture. In case of storing the fertilizer, using airtight container should be avoided. It can be stored for one year or more.