Larger Scale Worm Composting


    Here I give some details on a method for doing larger scale worm composting. There are many different larger scale worm composting techniques. A little google searching will reveal many ways to cultivate worms. This method works well, is pretty simple and does not require complex or expensive equipment. This method is a great way to easily produce lots of wonderful vermi-compost. Vermi-compost makes it much easier for farmers to be successful organic farmers.

    I'm using this method in a tropical environment (in the state of Kerala in south India). The temperature here is pretty warm all year round so I don't have to worry about any cold weather. If you live in a climate that has a significant cold season, you will need to modify this method or use another method. It's actually pretty easy to modify this method for cold weather; just use a building or room that has some reliable heating. The ideal temperature for earthworms is about 13C to 27C.

Basics and Overview of this Method.

    * The worm composting is done indoors to protect the worms from birds, direct sun and rain.

    * This method uses worm "beds" which are just large, long piles of worms, worm compost and their food. These piles are also called "windrows".

    * The worm beds are on a flat concrete floor and there is a short concrete wall all around the perimeter. This prevents water from flowing outside the worm cultivation area. The concrete floor prevents the worms from going into the dirt and leaving.

    * Because water easily flows out from the bottom of the worm beds onto the concrete floor, it prevents standing, stagnant water from accumulating in the bottom of the piles. Stagnant water can give rise to anaerobic bacteria which can kill the worms and be harmful to plants and people. I discuss more about watering the worms farther below.

open fram shed

Equipment and Supplies Needed for this Process.

    * A proper room with a roof and concrete floor (a smooth concrete floor is best).

    * A few buckets.

    * A reliable supply of clean water.

    * Newspaper, cardboard, leaves and sawdust or something similar.

    * A reliable supply of worm food (I'll discuss this more below).

    * Starter worms (discussed below).

     Find or construct a covered room with a flat concrete floor where birds, sunlight and rain cannot get in. Too much rain could drown the worms and direct sun could overheat and kill them. Ideally you also want the room constructed so water will not flow out (I'll explain about this later). The concrete floor also helps keep the worm beds cool which is good if you're doing this method in a hot climate. If you live in a tropical climate that is warm all year round, its OK for the sides of the building to be open. If the building has open sides, just put up some netting so birds can't get in. Birds love to eat earthworms!

Starter Worms.

     Get a starter supply of earthworms suitable for composting. Around 1/4 to 1/2 kilo of worms should do well to get you started. If you can get more, that will get you started quicker. You want to a get a species of earthworm that is a top feeder ("epigeic") rather than feeds deep in the soil. In this method the worms are fed by putting their food on top of the piles. Eisenia fetida, Perionyx excavatus, Eudrilus eugeniae and Lampito mauritii are species suitable for composting. Ask around in your community for someone who can sell you the worms. Or you can search online for a worm supplier. In many western countries it easy to go online and find a supplier who can ship you some composting earthworms. If you can find someone else who's already doing worm composting, that's great. Ask them to show you what they're doing.

    There are agricultural universities all over India and around the world. Contact the agricultural universities closest to you. Tell them you want to do some worm composting at home and that you want to get about 1/2 kilo of composting earthworms. Many agricultural universities will have them available or will know where to get them.

    Another option is to ask around and locate some vegetable farmers in your area. They will often know a farmer who is doing worm composting. The workers at your local vegetable stalls should also know about nearby vegetable farmers.

Note that it will take a while for the starter worms to multiply enough to make the large worm beds that I describe in the method. If the starter worms do not cost too much, you can get more than one batch of starter worms to start multiple beds.

worm castings on top of soil
Here's a way to collect your own earthworms: Identify worm-inhabited soils marked by visible earthworm castings on the soil surface (the soil needs to be organic and healthy and free of chemical pesticides and herbicides). Dissolve about 500gm jaggery (native sugar) or molasses and 500gm fresh cattle dung in 20 litres of water. Sprinkle on an area 1meter x 1meter. Cover with some straw. Leave the cattle dung lumps and cover with an old gunny (burlap) bag. Keep watering for about 20 to 30 days. A combination of epigeic (top feeding) and anecic native worms will aggregate here that could be collected and used.


    Create some "bedding" for the worms. Shred some newspaper or cardboard and add some soil and/or sawdust. Then add the worms to the bed and add water. Worms like about 80% moisture. So you need to add enough water so the cardboard and newspaper can absorb all they can.

Watering the Worms.

    Keep the worm beds moist and never let the piles dry out. How much water they need depends on your climate. The worm operation where I work is next to the ocean in Kerala where it's usually pretty humid, so it's not difficult to keep the worm beds properly moist. If you live in a dry climate, you may need to water your worm beds more often to keep them properly moist. In general, you want to add enough water so that some will leak out of the bottom of the piles. That way you know for sure enough water is in the pile. It's good when some water leaks out of the bottom of the pile, but if lots and lots of water leaks out, then too much water is being added.

    If excess water flows out from the bottom of the bed, that's no problem. It's actually a good thing. Just capture it with some dry shredded cardboard, shredded newspaper, sawdust or similar material. Sawdust is especially great to capture the excess water. After it soaks up the water, just put it onto the pile where the worms will start to eat it. If you put wet newspaper or cardboard on top of a pile, it's good to cover it with some worm dirt so it doesn't dry out.

    The excess water that flows out of a worm bed is called "leachate". If your worm beds are in good shape and properly aerobic, the leachate should be safe to use. Test out some of your leachate on different plants to see the effects. Don't add too much! Just add a little bit of leachate around the base of the plant. Then observe how the plant reacts. IMPORTANT: Use the leachate quickly! It must be used within a few hours after it leaks out of the piles. If you let it sit in a bucket or container for more than a few hours, then it may go anaerobic which is bad. If the leachate smells bad, don't use it.

healthy worms in soil
    If your worm beds have lots of wriggling worms and they look healthy, then you're probably doing things just right. If you see lots of worm leaving the worm beds, then something may be going wrong (too much or too little water or food, or the temperature in the pile has gotten too hot). If your worm bed ever starts to smell bad, then it must be quickly thrown out.

    When the worm beds start to get about 25cm to 30cm tall, then their centers may start to heat up. The heat is due to organic material in the center being composted by aerobic bacteria (aerobic (air breathing) bacteria is good bacteria). This should not be a problem for the worms because they'll simply move away from the heat to the outer portions of the pile. Also, if the piles are watered sufficiently, the water will soak into the center and cool it down.

    Keeping the piles always moist will also discourage ants from coming to the piles. If the piles get dry, ants may come and steal away the some of the worm eggs. Ants and worms have evolved together for millions of years so they've learned how to get along together pretty well.

    Another way to keep the piles cool and moist is to put some water soaked natural fiber burlap bags on top of the piles. Keep the burlap bags moist every day and that will help keep moisture in the piles. From what I've seen, worms seem to love wriggling around in burlap bags. The burlap bags will slowly decompose as they're eaten by worms and good bacteria. To feed the worms, just lift up the burlap bags, pour on the liquid food (or bury the solid food) and then lay the bag back down in its original place.


    For a smaller worm operation, it's not difficult to shred enough cardboard, newspaper and leaves by hand and using scissors. You can use a good pair of scissors to shred the leaves. For a larger worm operation, you may need to research getting some kind of small shredder. There are various types of leaf shredders available, electric and hand operated. I've heard of people using cross-cut paper shredders to also shred leaves. Shredding makes the materials smaller which means the worms will be able to eat it more easily and it will decompose quicker. A cross-cut shredder will produce the best material for worm beds and for absorbing the excess water that leaks out of the piles.

    The worms will eat whatever organic material they can get into their mouths. But, obviously, the mouth of a worm is pretty small; that's why shredding is very helpful. In addition to eating small bits of organic material, the worms will suck off bacteria that is growing in organic material (and almost all organic material has some bacteria growing on it). Bacteria is a main food source for worms.

Things NOT to Feed to Worms:

    * Citrus (lemons, limes, oranges, pineapple, etc.). Worms do not like acidic foods.

    * Hot, spicy foods.

    * Too much oily food (a little bit of edible oil in the food is OK).

    * Meat, chicken or fish.

    * Moldy or rotten foods.

    * Any foods with lots of dairy. It's easy for the dairy to go sour and this could harm the worms. If there's just a little bit of dairy in the food, that should be OK. Just make sure to feed it to the worms quickly before it goes sour.

    * Don't feed the worms any food that smells bad!

    * No chemicals of any kind!


     In a natural forest, grasslands or organic farm, the worms will mostly eat decaying leaves and other decaying plant matter. In your operation, you can give them food that will encourage them to grow faster and to breed more. It's always good to chop the food into smaller pieces if you can. The worms can eat it faster and it will decompose faster. Foods that worms like are:

    * Cow, pig or horse dung. The dung must be fresh and not too old. If you get dried dung, just soak it in some water until it's soft and mushy.

    * Tea and coffee grounds are great. They're small particle size and easy for the worms to eat. In India and around the world there are many chai (tea) shops and stalls. See if you can get their leftover chai grounds. Remember to use it quickly! Within 12 hours or so. The chai grounds will likely have milk in them and it can go sour quickly. Never feed sour milk to worms. If you live near a coffee shop like Starbucks, ask them if they'll give you their leftover coffee grounds.

    (Dung, tea, coffee grounds and other soft mushy foods can be mixed with water to create "liquid worm food" that is poured on top of the piles. Solid foods like fruit and veggie peels should be buried in the pile.)

    * Fruits and chopped fruit peels like apples, pears, papaya, bananas, mangoes, etc.

    * Chopped vegetable peels.

    * Egg shells are OK and it's especially good if you crush them first. Egg shells add good minerals to the worm compost.

    * Any kind of soft food that doesn't have any of the things not to feed them (see the list above for foods to avoid).

    It's usually good to bury the food a little bit into the pile. That way it won't get moldy and flies can't get to the food. One way to bury the food is to put the food on top of the pile, then scrape up some dirt from the edges of the pile or from another pile and spread it over the food waste. Flies and fly maggots won't harm the worms, but the flies are a nuisance and they carry disease. So always make sure the flies can't get to the food.

    If you have a blender, you can blend the fruit and veggie peels into a liquid that can be poured on top of the piles. This liquid food should be covered with sawdust or some worm dirt to discourage flies.

    If there are some restaurants or other food establishments near your worm operation, go visit them and see what kinds of leftover food and food waste they're throwing away. They may be throwing away foods that are perfect to feed your worms. And they may be very happy to give it to you at no cost.

     When worms have a good environment with proper water, food and temperature, they'll multiply rapidly and double their numbers every 2 months or so. As the worm population grows, you can feed them more.

IMPORTANT: Don't overfeed the worms! If you do, the food may start to rot before the worms can eat it all. Rotten food can ruin the worm pile and kill the worms. So before feeding the worms, check and make sure they've eaten most of the food from the previous feeding.


    In this photo on the left you see the long piles of worm beds. These are called "windrows", I always feed at the front of the windrow. I stop feeding and watering the back of the windrow when the pile is tall enough to harvest. The worms will naturally keep moving toward the front of the windrow where it's more moist and has food. You can also see where the water has leaked out.

    The worm operation where I work is located next to a larger thermophilic compost operation (thermophilic composting does not use worms and is good for composting large volumes of food waste). I use the fine filtered compost from there to capture the water (also called "leachate") that leaks from the bottom of the worm piles. I sprinkle the regular compost on the ground and the next day it has soaked up all the leachate. I then scrape it off the concrete floor and use it to make new worm beds. The regular compost when soaked with leachate makes a good worm food.

    In the worm operation where I work, we use a combination of some windrows and some piles. We're exploring the advantages and disadvantages of both methods. Both seem to work well.


    Once a worm pile gets to be about 30cm high, it's time to harvest the worm compost. To harvest, shine a bright light onto the worm pile. Worms don't like light and will burrow into the pile to get away. Gently scrape off the top layer of worm compost and put it into a bucket. Don't worry about getting out every single worm. Some worms are small and it's no problem if a few of them get harvested along with the worm compost. As you scrape off the top layer, the worms will continue to go further down. Continue this process until you've harvested all the worm compost you want.

There are designs for rotating worm harvesters that you can build yourself or buy. Just do a google search for "worm harvester".
rotating worm harvester
An example of a worm harvester can be found here If your worm operation becomes large, you'll want to explore getting a worm compost harvester to reduce your labor needs. As you can see from the picture, the worm harvesters are not too complicated. A good mechanical hardware shop should be able to build one.

Baiting the Worms.

    A good harvesting technique is to put some fruit peels like papaya or melon peels juicy side down onto the pile. The next day when you lift up the peels you should see lots of worms right under the peels. Gently grab the worms and move them to another pile or put them in a bucket.
    This is an easy way to quickly get worms out of the pile. The more worms you remove from the pile the easier it is to harvest the compost. The worms you collect can go into any new piles you're creating to help them build up faster.

Using the Worm Compost.

    Worm compost is the richest and most powerful organic fertilizer. It's more potent than regular compost. You only need to use about 20% worm compost when using it to make potting soil or using it in your garden or farm. Worm compost contains the perfect balance of nutrients for plants and it's filled with special plant growth hormones and organic compounds that are not found in any other type of compost. Worm compost is very valuable! This page has some more details about making and using vermi-compost.

Getting Help if You Run into Problems.

    If you encounter some problems with your worm operation, there are a number of good online worm composting forums where you can post your questions and get advice. Just do a google search for "worm compost forum" or "vermi compost forum". Then register and post your question.


Save Nature!
    Remember: Chemical fertilizers and chemical pesticides slowly destroy the soil and the creatures in the soil. Organic fertilizers like worm compost make the soil more healthy and increase soil bio-diversity. Healthy organic soil creates healthier plant immune systems so they can easily fight off pests and diseases. So avoid chemicals and buy organic foods if you can.


    Once your worm operation is up and running successfully, you can invite groups of local school children and their teachers to come and visit. Kids like seeing the worms and it's a great way to raise environmental awareness in young people.
child holding worms
Encourage the teachers and kids to start their own worm compost bins in their school rooms. They're easy to set up and maintain. For full details, just follow the link to "Worm Composting" in the upper left menu on this page.   


    All around the world, worm compost is a valuable commodity and can be easily sold to eager buyers. The worms can also be a valuable product to be sold as bait for fishermen. Here in India, there are a number of small businesses doing worm composting and making a nice profit. Also many gardeners and organic farmers have worm composting operations. Their worm compost increases the yields and profitability of their crops. Your local garden shops and plant nurseries may be eager to sell your worm compost to their customers. If there are community gardens in your area, the gardeners there may also be eager to purchase your worm compost.

    If you want to sell your worm compost, it's good to cure it first. When initially harvested, the worm compost may be quite moist (this is good because worms like moist soil). Curing allows the compost to dry out so it's not so heavy and easier to transport. Just spread the worm compost out in the sun or on the floor on in a flat shallow container like a large garbage can lid. IMPORTANT: Don't let the worm compost get completely dry! It should have a little moisture (about 30% moisture is ideal). So if you cure the worm compost in sunlight, monitor it carefully and take it out of the sun before it totally dries out.

So keep in mind this is just one way of doing larger scale worm composting. If you're new to worm composting and want to start doing it, the best thing is to do some research. Find people who're already doing it well and ask them lots of questions. On the net there are thousands of sites that discuss worm composting. Also (as mentioned earlier) you can register with a worm composting forum to post your questions and get answers from experienced worm composters.

    Feel free to contact me if you have any questions: My name is Advait and my email is I'm located in Kerala, India.