Vermicompost is vital to good soil. In the previous article on Organic Farming one of the sections dealt with soil and how important having healthy soil is to Organic Farming as a healthy soil equates to healthy vegetables and cattle. One of the main contributors to this process is the lowly earthworm. However, more and more people nowadays are realizing how useful this little animal is. The casts, or the manure that is produced by earthworms, is called vermicompost.
The humble earthworm’s activities result in numerous advantages:
1) If you start your own vermicompost heap you generate an endless supply of cheap compost that is chemically-free, eco friendly and uses up biodegradable matter that before one would dispose of.
2) The vermicompost is friable and improves not only the structure of the soil, but also the rate of water retention.
3) The soil is enriched. The concentrations of nitrogen, calcium, magnesium, and phosphates are all higher in soil that has earthworms.
4) Vermicompost also suppresses certain types of weeds that would have grown if the compost were not present.
5) It promotes better root growth and structure, and is an excellent medium for growing seedlings and seeds as it enhances germination and crop yields.
So now that we know the benefits of worm farming, how do we go about setting up a small worm farm and what sort of bin should you choose?
What Size of Bin and Type of Bin is Best for you?
For each 500 g (1 pound) of food waste produced each week, you will need at least 30 cm squared (1 ft squared) of bin space. Therefore choose the size of bin that is appropriate for your size family. As a benchmark for 2-3 people you should have a bin measuring 60 x 60 x 30 cm stocked with 1 kg of worms.
Most small bins for vermicompost use can be grouped into three categories:
1) Non-continuous : An undivided container, a layer of organic matter is placed in the bin lining the bottom. Worms are then added and organic matter for composting is added in a layer above the bedding. Another layer is added on top of the organic matter and the worms will start to compost the organic matter and bedding. This type of bin is often used because it is small and easy to build. But it is relatively difficult to harvest because all the materials and worms must be emptied out when harvesting.
2) Continuous vertical flow : A series of trays are stacked vertically on top of one another. The bottom tray is filled first, in a similar fashion to the non-continuous bin, but is not harvested when it is full. Instead, a thick layer of bedding is added on top and the tray above is used for adding organic material. Worms finish composting the materials in the bottom tray and then migrate to the one above. When a sufficient number of worms have migrated, the vermicompost in the bottom tray can be collected and should be relatively free of worms. These bins provide an easier method of harvesting, as they do not all have to be emptied out.
3) Continuous horizontal flow: A series of trays are lined horizontally. This method too relies on the earthworms migrating towards a food source in order to ease the process of harvesting. The bin is usually constructed to be similar to a non-continuous bin but is longer and lies horizontally. It is divided in half, usually by a large gauge screen of chicken wire. One half is used until it becomes full, then the other half is filled with bedding and organic matter. In time, the worms migrate to the side with the food and the compost can then be collected. These bins are larger than a non-continuous system but still small enough to be used for small-scale worm farming, with the added advantage of being easier to harvest.
Setting up a small-scale Worm Farm
Setting up the compost bin is easier than you may think. All you need are the following:
* A plastic bin with a lid to keep away the flies and to cut down on odours while the matter is decomposing. However, your worms will need oxygen, so drill holes in the bottom of the bin for ventilation and drainage and further help this process by placing the bin on some bricks to elevate it off the ground.
* Place some bedding in the bin for the worms in the form of either shredded paper (that from a mechanical shredder is perfect as it is really fine), peat moss or shredded coconut hair (coir) that can be commercially bought. Do not use glossy paper or magazines. This should not be more than about a fifth of your bin space. Remember that the worms eat the bedding, so you need to replenish this every few months.
* Water to dampen the bedding. Make sure that you do not flood the bin with too much water. You just want to make the bedding moist.
* Get your food scraps that you have been saving up. The best scraps are fruit and vegetable peelings, fruit skins, apple cores etc. If you want to help your worms along, some of those scraps could be liquidised in a blender to quicken the process. Additions such as cow, sheep, pig or chicken manure is a bonus, but it is not a necessity.
* In setting up your vermicompost avoid feeding the worms the following: meat, fats or dairy products, citrus, onions and garlic, fish, bones, tobacco, or pet or human manure. Too much fat prevents the earthworms from breathing properly as they breathe through their skin. Also avoid using too many watermelon skins as they really don’t have a lot of nutritional value for the earthworm and they also disrupt the moisture levels of the compost. If your lawns have been sprayed with any weed killer avoid feeding these clippings to the worms.
* Now it is time to place your worms into the bin. The type of worm is important and the red worms are the ones to get. These are called composting worms and known as Red Wigglers (Eisenia foetida) or Red Earthworms (Lumbricus rubellus). Make sure that you do this on a sunny day and that the sun is shining into the compost bin. Earthworms do not like the sun and they will immediately start digging down into their new home. If you do not have the sun shining for this exercise you may find that most of your worms have crawled out of the bin and left for greener pastures! The worms can be bought commercially, including over the Internet.
* Now cover with two handfuls of soil to the bedding in each bin to supply “roughage” for the worms. Adding crushed eggshells provides not only roughage but also calcium for the worms, and it lowers acidity in the bin. Now put the lid down on the bin.
Where should you Place your Vermicompost Bin?
Many people actually like to keep their bin inside, either in a garage, basement, kitchen or laundry area. Personally, I do not think that compost bins belong indoors at all. Rather place the bin in a sheltered area out of the sun. In winter, you could move the bin to the garage, or surround it with some form of shelter like hay bales to keep the snow, rain and cold out.
Maintaining your Vermicompost Bin
You have to make sure that you have enough moisture in your bin, without it getting too wet, and
making sure that the compost is alkaline rather than acidic. You should turn the bin contents over on a regular basis, it’s best to do this every 3 days. Your worms require 3 things to exist: i) Oxygen ii) Moisture iii) Food Scraps iv) A dark place to live
If all requirements are met your worms will live quite happily in their new environment and will also procreate. Adult worms produce three cocoons a week and each cocoon will contain at least three baby worms and sometimes ten or more. Every three months the worms should be harvested or separated from the castings.
Make sure that your soil never smells sour. If this happens it means that the soil is too wet. If it smells sour then add calcium carbonate, also known as garden lime which is very different to ordinary lime which will kill your worms, crushed egg shells, dirt, sand, or more newspaper to soak up that excess moisture.
So how wet should your compost be? – About 75% moist. What exactly does this mean? I can already hear you ask. Well, if you take a handful of matter and squeeze it hard you should only get about a drop or two of liquid. This is just how your worms like their environment and will be quite happy to stay.
No only will they be happy to stay they will also multiply. If conditions are good, you will double your worm population in six months. If the worms become crowded and you do not remove any, then worms will slow down their reproduction.
Feeding your Worms
There are two methods of adding food scraps to the bin.
* Top feeding: This is when food scraps and biodegradable matter is placed directly on top of the existing layer in a bin and then covered with another layer of bedding and soil. This is repeated every time the bin is fed.
* Pocket feeding : A top layer of bedding is maintained and food is buried beneath by drilling down into the bedding. The location of the food is changed each time, rotating around the bin to give the worms time to decompose the food in the previously fed pockets. The top layer of bedding is replaced when necessary.
One pound of worms will eat about three and one half pounds of food scraps a week. If you add more food than your worms can handle, anaerobic conditions will set in and cause odour. Make sure that food scraps are always buried under the soil to avoid attracting flies and rodents.
Knowing When and How to Harvest the Vermicompost
Smaller scale worm bins are harvested in a variety of ways, and the length of time it takes for the process to be completed really depends on a whole range of variables including the size of the container to start off with. In all cases, harvesting should begin when the bedding and consumed food has turned a rich dark brown. It should be moist and crumbly, with a consistency of coffee grounds.
After about six weeks, you will begin to see worm castings (soil-like material that has moved through the worms’ digestive tracts). Castings can boost plant growth, since they are rich in organic matter and the nutrients plants need to thrive, and are pulsing with biological activity that will bring life to your soil eco-system.
After about 4 months it will be time to separate the worms from the compost. If you have a non-continuous or undivided container, it is more difficult to harvest the worms. However, this situation is certainly not impossible. Take the contents and turn it upside-down on a piece of plastic such as a ground sheet or a tarpaulin. Because the earthworms are photosensitive, if this is done on a sunny day the worms will start burrowing down, and then it is easy to start scraping the compost from the top, waiting in between for them the move downwards. Wait 20-30 minutes before starting to scrape off the top layer of compost.
If, however, you are the impatient type, get yourself a fine meshed sieve, the type they use in construction yards, if your compost heap is fairly large, or a large household sieve will do. Sieve the compost until you have finely granulated composted on one side, and your worms in the other to start the process all over again. Do not be lazy and put the worms into your soil along with the compost. It is not that the worms will damage your plants in any way, but red worms are not worms that will survive for any length of time in such soil. In nature, this type of worm lives in mild climates in the leaves on the forest floor or in manure piles.
Be on the lookout for worm eggs. They are lemon-shaped and about the size of a match head. They are shiny in appearance, and are light brown in colour. The eggs contain between two and twenty baby worms. Although it is time consuming, you may want to return the eggs to your bin so they can hatch and thrive.
Another way to harvest the compost is to move the compost to one side of the box and add fresh bedding and food to the other side. Then only bury food on the new side. In six weeks, the worms will have migrated to the new bedding and you can harvest the finished compost, and replace it with new bedding.
Now that you have all this compost how are you going to use it?
You can use your vermicompost straight away or store it and use it later. It will be good for about a year. Mix it into the top six inches of soil in your garden and around your trees and plants. You can also use it as a top dressing on outdoor plants or sprinkle it on your lawn like you would as if you were top-dressing. Vermicompost makes great nutrient-rich mulch so is perfect for areas that do not get lots of rain for moisture retention.
For indoor plants, you can safely mix vermicompost with your potting soil. Regarding indoor plants, make sure that you have removed all worms and eggs from the compost as they will not survive in an indoor pot.
You can also make a “compost tea” to feed to your plants. An easy recipe is to add two tablespoons of vermicompost to one quart of water and allow it to steep for a day, mixing occasionally. Water your plants with this “tea” to give them a boost.