How To Maintain A Vermicompost Bin

Vermicompost is the most popular and successful form of compost. It is the process of using redworms and other organisms to decompose organic matter into effective fertilizer. It is especially popular because it is so easy to maintain. Just follow these basic guidelines and you are sure to have a healthy, happy vermicompost ecosystem.


Redworms, like the popular Red Wrigglers, will be the most active from 60 to 80 degrees F. If you want your worms to operate and maximum capacity, you should maintain a temperature near the high-end of this range. They will remain somewhat active above 40 degrees, but will die under the freezing point. This is a fairly universal range for any type of compost.

In a cold environment, this means that you must insulate your compost well. The little ecosystem inside your compost produces its own heat and can survive even during winter months with adequate insulation. You can pile hay around your compost, bury the bin into the ground or even bring it inside.

Some more hardcore enthusiasts keep their vermicompost in their living space as it normally does not smell. However, mold, fungus, mites and flies are also in your compost, so this behavior is discouraged. Garages or sheds are suitable. If your garage is heated, you can even achieve high output all year.

If your area experiences particularly harsh winters, and bringing your compost inside is not an option, you may need to simply allow your worms to die and replace them the following spring.


Worms breathe through mucus membranes on their skin and need a moist environment to do so. The moisture should be around the same level of most planting soil. If you pick up the compost with your bare hand, it should be like a well-wrung sponge: wet to the touch but not dripping.

While moisture is necessary, refrain from watering the compost as you would a plant. If water collects at the bottom of your bin, the worms will not be able to breathe there and bacteria will become overly abundant. This will kill worms and make the compost stink like damp garbage. Instead, add only very small amount of water—once a day, at most.


A rule of thumb is to treat your worms as vegansno dairy, eggs, fish or meat. Of course, your worms are really omnivores, but if you feed them any animal or high-fat products, your compost will stink. Animal products also attract unwanted pests.

Worms will love just about any food that you would otherwise throw away, like vegetable peels, melon rinds, pizza crusts and any other vegetarian fare. However, there are a few small limitations:

  • Citrus Rinds - Should be added only sparsely. The acidic quality can harm the worms and will not be eaten until bacteria has partially processed them anyway.
  • Salt - Can burn the worms, so add salty foods sparingly and distribute them evenly.
  • Bread - Only include if they are whole-grain and do not contain preservatives. Anything else will take too long to break down and can even contain anti-fungals that kill your compost.

Preventing Unwanted Pests

One of the greatest qualities of vermicompost is its lack of enemies. You may notice all sorts of creatures in your bin such as mites, potato bugs, mold, fungus or other worms. These creatures are good. They are a vital link in the decomposition chain, eating what the redworms can not. However, you may want to limit their presence for your own comfort.

Mold is a good friend of your vermicompost, but not entirely necessaryand you may be allergic. Mold is a sign that your worms are not decomposing their feed quickly enough. Reduce the feed and mold should abate.

Fruit flies lay down eggs that hatch as maggots. Maggots are some of the most efficient decomposing agents around, but the presence of both the adult flies and their maggots may be very unwanted. You can prevent their intrusion in several ways:

  • When feeding, bury the new matter well below the top bedding.
  • Place a few layers of damp newspaper over the compost.
  • Hang any sort of fly trap near or directly over the compost bin.

This last tip is specific to flies, while the first two will also discourage other pests by limiting the bin's smell.

How Many Worms?

If you have started off with an appropriate number of worms (about 1 pound per 5 gallons of compost) and are providing a happy home, then the worms will procreate at a natural rate.

They will grow to a population suitable to their conditions. It is better to allow your worms to grow by their own will than to add too many yourself. Doing so could cause famine, weakening or killing the worms.