Composting
Vermicomposting - A Complete Guide
Vermicompost is the castings (worm castings) of earthworms. Worm castings are nothing but excreta of the earthworms. Earthworms are fed with soil/any organic waste, this waste gets digested and excreted by them. As these wastes have already undergone the breakdown, they do not need further decomposition. Worm castings will be rich in nutrients when earthworms feed on kitchen waste or any other organic waste rather than just soil. These worm castings contain water-soluble nutrients, that can be readily absorbed by plants.
Composition of Vermicompost:
Vermicompost contains most macronutrients, and its nutrient composition is often greater than the regular garden soil.
:
|
Element |
Content |
|
|
1 |
Organic carbon |
9-17% |
|
2 |
Nitrogen |
1.5 - 2.1 % |
|
3 |
Phosphorus |
1 - 1.5 % |
|
4 |
Potassium |
0.15 - 0.5 % |
|
5 |
Calcium and magnesium |
22-70 me/100 g |
|
6 |
Sulphur |
128 -548 mg/Kg |
|
7 |
Copper |
100 ppm |
|
8 |
Iron |
1800 ppm |
|
9 |
Zinc |
50 ppm |
| Go through the links below to know about other types of composting: 1. Composting and its types 2. Aerobic composting and its types 3. Anaerobic composting and its types 4. Indoor /bokashi method of composting 5. Special methods of composting (Indore, Banglore, Coimbatore, NADEP) |
Advantages of vermicompost:
- It improves soil structure and texture
- It improves the aeration of the soil
- Attracts deeply burrowed earthworms
- Increases the water-holding capacity
- Free of weed seeds, chemicals, and harmful pathogens.
- Easy to handle, apply and store
- Do not hold any bad smell
- It can be used as a soil conditioner or amendment.
- Encourage the population of useful soil microbes in the soil.
- Increases the natural decomposition ability in the soil.
Preparation of vermicompost:
Essentials required to prepare vermicompost at home:
- Suitable site/place
- Container
- Bedding material
- Food source/organic waste (biodegradable)
- Proper aeration
- Moisture
- Ph
- Earthworms
- Covering material
1. Suitable site
Earthworms need a cool, shady/dark place with high humidity to produce vermicompost efficiently. The temperature of the selected area should not be high or low than the required level (55-85 ℉) as it directly affects the feeding and breeding rates of earthworms.
2. Container:
Image source
Select a container (wide containers are preferred to deep ones to ensure proper aeration throughout the container) that has less height/depth.
- Make some holes at the bottom of the bin/container to drain out excess water if present
- Make holes at the body of the container too (for exchange of gases).
3. Bedding material:
Any material that could create a suitable habitat for earthworms is known as bedding material. Choosing the right bedding is very important as it occupies 3/4th of the bin and earthworms also obtain food from it. Good bedding material should have the following properties.
- Good water/moisture-holding capacity: Earthworms need moist conditions to thrive. Their skin becomes dry (skin needs to be moist all-time) and they eventually die if the bedding material has no moisture content. So the bedding material should have good water holding capacity for a longer period.
- Good bulking potential: Bedding material should not be packed too tight. Earthworms breathe/respire through their skin. Air/oxygen gets dissolved and enters the bloodstream through their moist skin. So the bedding material has to be loose/porous to allow the passage of air through it.
- Low nitrogen content (high C:N ratio): Materials that have high nitrogen content like green leaves, fresh manure cannot be used as bedding materials as they tend to decompose faster and release heat in the process. This increases the temperature inside the containers and creates lethal conditions for earthworms. However partially decomposed materials/browns (high carbon content) can be used as bedding materials.
Materials that can be used as bedding materials are:
- Dry leaves: Need to be moistened by spraying water.
- Cardboards: Soak in water for 15 min. Take them out and tear them into pieces. Squeeze them before use to remove excess water.
Image source, Image source
- Newspaper: Tear them longitudinally, soak them in water for 10 min. Now take them out, squeeze and use them as bedding materials.
- Straw/hay: Should be soaked in water for some time and squeezed before use.
- Garden waste (dried plants, twigs, leaves): Should be broken into pieces and soaked in water for 2 hours so that they get softened. Drain all the excess water and keep it aside for some time before use.
- Sawdust: Should be moistened by spraying water
- Wood chips: Should be soaked in water and dried (can’t squeeze) to remove the excess water
- Horse manure: Need to be moistened if dry.
- Peat moss: Excess water should be removed by squeezing.
Moisture content in the bedding material plays a very important role in vermicomposting as dry conditions kill earthworms, while waterlogged conditions drive them away from the bin/pit/container.
|
Bedding material |
Water-holding |
Bulk potential |
C:N ratio |
|
Dry leaves |
Low-medium |
Low-medium |
40-80 |
|
Cardboard |
Good |
Medium |
563 |
|
Newspaper |
Good |
Medium |
170 |
|
Straw/hay |
Low |
Medium-good |
Hay: 15-32 |
|
Sawdust |
Low-medium |
Low-medium |
142-750 |
|
Wood chips |
Low |
Good |
Hardwood: 451-851 |
|
Horse manure |
Medium-good |
Good |
22-56 |
|
Peat moss |
Good |
Medium |
58 |
Instead of a single material, you can also use a combination of these bedding materials to create a good habitat for earthworms.
Problematic bedding materials:
- Fresh leaves/manure tend to increase the temperature in the worm bin and make it unsuitable for earthworms.
- Garden wastes should be collected only from organically maintained gardens, as chemically treated wastes harm the earthworms.
- Wood chips or sawdust from wood that is treated with pesticides (to keep the wood-eating insects away) should not be used
- Freshly cut woodchips that have sharp ends/hairy structures cause physical damage to the earthworms.
- Bedding material should not be contaminated with pieces of materials like metals, glass, ceramics, thorns.
- Non-absorbent materials should not be used alone as bedding materials.
Image source
4. Food source/organic waste:
Organic waste should be biodegradable and can be of plant or animal origin. This organic waste acts as a food source for earthworms. The goodness/fertility of the vermicompost completely depends on the food materials you choose to feed them. Materials that can be used as worm food are
|
Food wastes |
Advantages |
Measures to follow before use |
|
Kitchen scraps (vegetable and fruit peels, leftovers, stems of leafy greens, spoiled/rotten vegetables) |
Easily available and contains good moisture and nutrients |
Should be composted before use to avoid heat production(create unfavorable conditions for earthworms)and pest attraction. |
|
Cow dung |
Easily available and contains a good amount of nutrients |
Should not be used fresh. It should be pre-composted for 15-20 days before use |
|
Sheep/goat manure |
Nutrient-rich |
Should be pre-composted |
|
Poultry manure |
Rich in nitrogen content |
Should be used in fewer quantities as it contains high nitrogen. It needs to be composted if used in high amounts. |
|
Organ waste of Fish/poultry |
Good food source for earthworms. |
Should be composted until 3rd phase of composting i.e. Thermophilic stage. |
|
Corrugated cardboard |
The glue used to hold the layers is protein-rich and can be a good source for earthworms |
Should be shredded (made into pieces) and soaked in water for few hours before feeding them to worms. |
You can use the combination of these wastes to feed your earthworms. Collect the materials (cow dung and other wastes in the ratio of 1:1 to 1:3) and pre-compost them for 15-20 days before adding them to your worm bin.
Usually, earthworms consume half of their body weight per day (more in favorable conditions). So if you are adding 1 kg of earthworms, add 600-750 g of organic waste to your worm bin.
5. Aeration:
- Compression of bedding material or organic wastes should not be done as this eliminates the air pockets and reduces the oxygen availability to earthworms.
- Excess moisture reduces the oxygen availability and drives earthworms away.
6. Moisture:
The perfect moisture level is very important to get quality vermicompost. Worm bins should neither be dry nor watery. 60 -70% moisture level is ideal for vermicomposting.
7. pH :
The ideal pH for the earthworms is 6.0 - 7.0 but due to the decomposition of organic matter, pH of the worm bin becomes acidic. In general pH range between 5.0 - 8.0 works well for vermicomposting.
8. Earthworms:
Red wigglers (Eisenia foetida), Red earthworms (Lumbricus rubellus), European nightcrawlers (Eisenia hortensis), African earthworms (Eudrilus eugeniae) composting earthworms (Perionyx excavatus) are the important groups of earthworms that are mostly used in this process. Red wigglers are the most common and widely used earthworms for vermicomposting.
Image source, Image source
Usually, earthworms consume half of their body weight per day (more in favorable conditions). So if you are adding 1 kg of earthworms, add 600-750 g of organic waste to your worm bin.
9. Covering materials:
Usually, moist gunny bags are used to cover the pits/bins of vermicompost. If the gunny bag is not available materials like wet hay or straw can be used. Make sure the covering material holds moisture and does not allow light through it. If it has no moisture holding properties, moisture loss will be more. If it allows light, earthworms do not feed on upper layers of the organic matter.
Steps to prepare vermicompost:
- Select a suitable site as mentioned (cool, shady with high humidity)which should be away from direct sunlight.
- Take a wide container (not much deep) punch/drill holes to drain excess water.
- Place stones or thin mesh to prevent the escape of earthworms.
- Add any/combination of bedding materials as mentioned.
image source, image source
- Sprinkle/spray some water.
- Add any/combination of the organic waste (600-750 g/1000 g of worms) that is pre-composted for 15-20 days.
Image source - Add water evenly to moisten the organic matter.
- Now add earthworms (1 kg, i.e. 1000 worms) into the worm bin.
- Wait until earthworms get inside the organic matter (they bury inside the organic matter to avoid light).
Image source - Now cover the bin (entire bin) with moist straw or gunny bag and make sure light does not pass through it.
- Add food materials from time to time (300-400 gms/2-3 days). Adding food completely depends on the feeding rate of your worms. So feed them accordingly.
- Add water (once in 2-3 days) to maintain the moisture in the worm bin.
- You can disturb the bin by giving a slight mix by gardening fork once in 10 -15 days to ensure the proper aeration in the bin.
- Vermicompost will be ready to harvest within 2-6 months (depends upon the type of earthworms and organic matter used).
- Do not add water 2-3 days before harvesting.
- Collect the vermicompost from the top.
Tips:
- Add water by checking the moisture content in the vermicompost bin.
- Do not add chlorinated water as it alters the pH of the medium.
- Do not crush peds of cow dung or manures as they are used by earthworms to lay eggs by entering inside them.
Image source - Adding combinations of bedding materials or organic wastes is beneficial than using a single type.
- Add food materials only when needed. Adding excess amounts results in the rotting of food materials before earthworms feed on them.
- A fetid worm bin may be a sign of overfeeding of earthworms. This indicates, earthworms consuming more than half of their body weight. In this case, add a little more food to make your worms happy.
- You can place the worm bin on the stand/at height and place a container below to collect the excess water. This leachate (water) contains nutrients and can be used to water plants by diluting it.
Image source
Harvesting vermicompost:
At the end of the composting, there will be less bedding and more castings in the worm bin. Do not add food for 2-3 weeks before you planned to harvest the compost. Stop adding water before 1 week of harvesting.
Remove the lid and expose the bin to light (sunlight/artificial light). By this earthworms start moving deep into the worm bin to avoid the light. Now collect the compost from the top. You can obtain the clear vermicompost by using a sieve so that it separates the organic matter, bedding material, or earthworms if left any. However, it can be done with hands too.
As you keep harvesting, it will be difficult to harvest compost at the bottom of the bin. You can insert 1-2 balls (so that it will be easy to remove) of fresh food material/cow dung (to attract earthworms) in the leftover compost. Within 24 hours, earthworms get trapped inside the balls so that balls can be removed (and introduced into a fresh worm bin) and compost can be collected.
Storing of vermicompost:
You can add the harvested vermicompost right away to your garden, potting mix, or pots to enrich the soil or you can dry it until it restores 40% moisture to store it for future use.
You can store it in an open place or in aerated container in a dark cool place. You can sprinkle water on it to keep it moistened. Drying out or exposure to sunlight will decrease the nutrient content and beneficial microbes in the vermicompost. You can store the vermicompost for 6 months to one year depending upon the method of storing.
Disadvantages of vermicompost:
- Needs a lot of care.
- Can’t be maintained easily as a beginner.
- Difficulty in separating worms from the vermicompost..
- Takes a long time for the preparation of vermicompost.
- Should keep a regular check on moisture and organic matter in the worm bin.
- May result in emissions of greenhouse gases like methane and nitrous oxide.
- May contain weed seeds (if used weeds in bedding or as food source).
Frequently asked questions
1. What is vermicompost?Vermicompost is compost made by feeding earthworms with biodegradable organic wastes. Earthworms digest these wastes and excrete them. This excreta (worm castings) contains water-soluble nutrients and highly benefits the plants and soil.
2. About how much bedding material should be used in the bin?
3/4th of the bin should be filled with bedding material as earthworms also feed on bedding material. Bedding material should not be packed tight to ensure the movement of earthworms through it.
3. Can I use cow urine to moisten the worm bin?
Yes. Besides moistening the bin, it also adds nitrogen and uric acid that are beneficial to the compost.
4. How long do vermicompost/worm castings work on soil?
Worm castings (vermicompost) contain water-soluble nutrients and can be readily available for plants. The nutrient supplement may last for 15-20 days so it is better to add vermicompost once in 20 -25 days.
5. What is the best bedding material for vermicompost?
Newspaper and cardboard are easily available and best bedding material for vermicomposting. However, using them along with straw/hay works wonders for your earthworms.
6. What is the best food source for vermicompost?
Some of the best food sources of earthworms are
- Fruit peels (except citrus fruits/rinds),
- Melon rinds,
- Vegetable scraps (like carrot/beetroot peels, stems/leaves of leafy greens, rotten veggies)
- Coffee grounds (used/spent),
- Dairy/beef manures.
7. What are the best earthworms for vermicomposting?
For the preparation of vermicompost, surface-dwelling earthworms should be used. Red wigglers (Eisenia foetida) are the most widely used earthworms for vermicompost. Some of the other best earthworms for vermicomposting are
Red earthworms (Lumbricus rubellus),
European nightcrawlers (Eisenia hortensis),
African earthworms (Eudrilus eugeniae)
Composting earthworms (Perionyx excavatus).
8. Can we use vermicompost for all plants?
Yes. We can use vermicompost for all kinds of vegetables, fruits, leafy greens, medicinal and ornamental plants.
9. How to add vermicompost to plants?
You can either add it in the potting mix (however should be added again) or on the top of the soil around the plant base. You can also prepare a liquid fertilizer out of vermicompost to use it for plants.
10. Where to buy vermicompost online?
You can buy the organic vermicompost at TrustBasket, which is completely pure without any additives like coal, coir, soil, or coco peat to increase its weight or quantity.
References:
Https://agritech.tnau.ac.in/org_farm/orgfarm_vermicompost.html
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