Worm composting (or Vemicomposting) is just what is sounds like, composting with worms. It can be done in a single small bin or in larger or stackable bins that can be stashed in or near your kitchen. You can use them to make smaller amounts of worm compost, or you can compost all of your kitchen waste this way and make a highly productive worm compost operation.
This post will take your through the basics of worm composting step by step. Next week we will post on the finer points of worm composting, how to increase productivity and how to set up your own household worm farm. So stay tuned.
Choosing Your Bin
You need a container to house the worms. This bin can be made of plastic or wood, and can be a single container, or one that stacks. Shallower beds tend to work better (12-18 ” high) as worms are surface dwellers, shallower containers help keep good air circulation throughout the bin. The bin can be many different dimensions, and the larger you go, the more worms you can house and the more compost you can produce. But as with most things, it really is better to start small, get a feel for it, solve some problems and then go bigger if you still want to. My bin at home is a simple Rubbermaid container from the local hardware store and is approximately 6″ deep, 1′ wide and 2.5′ long and it’s done me well for many years.
If you choose to build your own bin out of wood try to pick a wood that resists rotting such as cedar, or hemlock but do not use treated woods. You can build wonderful stacking bins from wood, or you can also buy stackable worm composters from gardening supply stores.
Setting Up Your Bin
Now you need to set up your bin to make sure your worms will be comfortable. First the bin needs to have air holes in the top of the box and drainage holes in the bottom. The air holes usually can be made by puncturing the plastic bin with a nail and hammer. For the drainage holes, it’s often helpful to use a hand drill and a larger drill bit to make larger holes for the water to come out of if it needs to.
Then you need to fill your bin with bedding, this is what the worms will live in, and eventually eat. It can be made from a variety of materials such as shredded newspaper, shredded fall leaves, or chopped up straw. You can mix in a bit of potting soil, or larger organic high carbon material to help fluff it up a bit if it’s all matted. Make sure any material you use is dried and not fresh (use brown leaves, not green etc.) Put the mixed bedding in the bin to a depth of 6-8 inches, and dampen the bedding. It should be consistently moist but not dripping.
Now The Worms
One of the best worms for your bin is the red wiggler. They reproduce happily in captivity and are great little food decomposers. The easiest way to get worms is to find a friend with a bin and get a handful of their worms to start. You will soon have a growing worm population of your own.
Place your red wigglers on top of the moistened bedding, and bury a handful of food in the bedding nearby. Keep the lid off and after a few minutes the worms should all disappear into their new home.
Where to Buy Worms in HRM:
- Lake City Farm, Jean Snow Ph: 902-461-0260 email: firstname.lastname@example.org
- Jen Stotland, worm composter
- Still having trouble? Email Garity Chapman at the Ecology Action Centre to be placed on a worm waiting list.
Finding a Place For Your Bin
Your worm bin can be located in a number of places: kitchen, patio, garage, basement or closet. The location should be dark and well ventilated. The temperature should not drop below 4 degrees Celsius.
If there is a spot, it’s best to keep it near you in the kitchen. If its small try putting it under the kitchen sink, if it is a stackable bin, put it beside your garbage can. This way it’s easy to put food waste in the bin regularly and to keep an eye on how the worms are doing.
Feeding Your Worms
Red wigglers will eat half their weight in food scraps every day. So for every pound of red wigglers, feed half that weight in food waste. Feeding once or twice a week is fine or every day depending on how productive you want the bin to be and how many worms you have in the bin. Until you get a feel for your worms appetite, only feed them as they finish the food you already gave them, that way you won’t encounter problems with fruit flies and mould.
Bury the food waste by pulling aside some of the bedding, dumping in the food and then covering it up. Each time you feed your worms, choose a different location. You can mark the last spot you placed the food with a skewer or other marker, and once that food has been eaten, it’s time to feed them again. If your bin starts to smell, you are feeding them too much or not burying the food sufficiently, so slow down and give them more time to eat.
|Foods They Like:egg shells (crushed)
coffee grounds & filter
fruit peelings (no citrus)
peanut hulls (no nuts)
|Foods To Avoid:dairy products
oil or oily foods
highly acidic foods
Harvesting Your Compost
Harvest your bin every 2-3 months, when the original bedding has turned into dark brown worm castings. You want to separate the worm castings from the worms, then put the worms back in the bin with fresh bedding. There are two methods to separate the worms from the compost:
1. Move the contents of the bin to one side, and add new food to the new bedding on the opposite side. The worms will leave the old pile for the new one in search of food. After a few days, remove all the finished castings.
2. Dump the contents of your bin onto a tarp or garbage bag and form it into a pile in a bright sunny area. Scoop the topmost layer off the pile and give the worms a moment to burrow deeper into the pile as they escape the light. Continue to scoop off thin layers as the worms burrow deeper until you reach the bottom where most of the worms will have collected.
The Finished Product
Worm compost is concentrated and filled with wonderful nutrients, so a little goes a long way! There are lots of ways you can use your compost year round such as:
- Add compost directly to your garden beds.
- Mix one part vermicompost to two parts potting soil to pot houseplants.
- Sprinkle some on top of the soil of houseplants as a fertilizer. (topdressing)
- Place a handful of vermicompost in the bottom of the hole when transplanting.
- Make compost tea with the worm castings
Common Problems and Solutions
You may be feeding the worms too much or too frequently, creating extra food waste that will sit and rot. Wait for the worms to finish their food before adding more, and give the bin a stir to allow fresh oxygen in the bin. Or if your bedding is made from leaves, they may have gone anaerobic, or in other words, they will be a smelly gooey mess. In this case, add some dry newspaper, mix it in and leave the lid open for a day or two.
Worms trying to escape
The worms may try to crawl out of the bin if the conditions are not suitable. Make sure the bin is not too moist, and if that is the case add some dry newspaper or dry, brown leaves to soak up the extra water. If the moisture levels seem okay the bedding may be too acidic, this could be due to adding to many coffee grinds, citrus fruits or other acidic foods. Add some crushed up egg shells, peat moss or fresh bedding and do not add more acidic materials.
The bin is attracting fruit flies
Discourage flies by burying the food waste and not overloading the bin. If the flies persist, you can move the bin to shaded spot outside where they will not be bothersome. Then move them back indoors as the weather cools and the fruit flies aren’t as prevalent.
Written By: Garity Chapman, Urban Garden Project Coordinator, Ecology Action Centre