Imagine you could turn your vegetable peels and scraps which you collect in a container on your kitchen countertop into a living soil conditioner plants thrive in rather than having it transported into landfill where it decomposes and creates methane – a gas worse than carbon dioxide for global warming.

And you wouldn’t need a lot of space to do so. In fact it could happen underneath your kitchen sink or on your balcony. 

What is a wormery and why bother?

The wormery is the environment, usually a container of some sort to provide a place for composting worms to live, feed and breed in.

The right kind of worms will digest and convert dead organic material  into high quality, nutrient rich worm casts (worm poop) and leachate.

If you already have a compost pile or bin in your garden you might wonder whether a wormery will add anything your compost heap doesn’t already do. The added benefit of worms eating the decomposed material is that it adds way more and varied microbes to the compost.

This makes worm casts an even better soil improver for nutrients and pest control than compost alone. 

The organic matter is usually waste from the kitchen like potato and banana peels, coffee grounds and spent tea leaves (take tea out of tea bags unless they are specifically labelled as compostable. Otherwise, you’ll be adding micro plastics to the soil.) 

You can also add garden greens or even manure from plant eating animals, horses, sheep, cattle, rabbits.

In that way a wormery is an increasingly popular method to make environmentally friendly use of kitchen waste. So let’s find out how a wormery works.

How to Start a Wormery: Creating an Environment Composting Worms Love

What Kind of Environment is Best?

A thriving wormery needs to provide the right conditions for composting worms. Composting worms are surface eaters as opposed to earthworms who live in deeper grounds. This means a wormery needs to provide a fairly large area with organic rotting materials as food. 

Underneath that feeding layer is bedding material. This needs to be a damp layer composting worms can easily wriggle through. When starting from scratch damp cardboard and shredded paper is great and easily available at no extra cost.

You can also buy a starter kit which usually contains a coir block for worms to make their home in.

The container needs to maintain the damp conditions but also allow air in so the veg scrap keep decomposing aerobically rather than anaerobically. The latter can happen when there is a lack of oxygen such as when the bin is to wet or if there are no air holes. 

Wormeries available to buy have therefore a sump and tap at the bottom to release any excess fluid, the leachate. This isn’t strictly necessary if you monitor the conditions inside the wormery carefully.

Many experienced womery owners regulate the temperature by adding liquid absorbing material like cardboard to the mix inside the bin. 

To summarize how a wormery works:

Composting worms are being added to an environment where they live in bedding they feel comfortable in. Comfortable means very damp and temperatures around 20 degrees Celsius. Food consists of organic matter like plant based kitchen scraps. Composting worms digest these and create nutrient rich vermicompost behind.

Which Worms are Most Suitable?

Composting worms are surface eaters as opposed to earthworms who live in deeper grounds. 

The worms used in vermicomposting are chosen because they eat a lot to process large amounts of food relative to their bodyweight. If conditions are right they can process about half their weight PER DAY! Allthough they can also go all out if food and temperatures are especially tasty for them and digest even more than their bodyweight.

Another characteristic is a good reproduction rate to ensure that the population keeps increasing. 

Lastly, the species need to be quite tolerant to varying conditions in their environment. 

This last point is also why a wormery is such an easy thing to have and keep healthy. 

As a rule of thumb, worms are most active and thrive at temperatures that are comfortable for people, so around 20 degrees but can tolerate at least 10 and up to 30 degrees Celsius. Composting worms also tolerate varying levels of acidity which will invariably happen when kitchen scraps are added. 

Likewise humidity in a wormery can vary depending on what kind of organic or brown matter like leaves, cardboard or paper is added.

A look into the bin shows that worms will move about quite wet areas as well as settle in more damp patches like in layers of cardboard. Just like with temperatures, taking care of a wormery is more about avoiding extremes like waterlogged layers and complete dryness. 

Composting worms have several names and it is best and safest to refer to the Latin ones.

The red wiggler (Latin name: Eisenia fetida, used to be spelled Eisenia foetida) is the most popular name and composting worm in the USA and Canada. Worm farms in the UK on the other hand favour naming the very same worm tiger worm due to it’s stripey appearance.

Another popular composting worm is larger European Nightcrawler.

What to Feed?

Most plant-based kitchen scraps will be devoured by the worms sooner or later depending how quickly it decays. This includes vegetable and fruit scraps apart from citrus fruits and onions.

Worms will not attack fresh kitchen waste right away. Usually freshly added food needs to sit in the bin for a few days until it decayed and is soft enough to be eaten by worms. How long it takes to be ready for worms really depends on the type of plant and also conditions in the wormery. 

Soft fruit like melon and flesh of an overripe banana will be gone and eaten within a few days. Harder and dryer parts like the stems of a pepper will take weeks to decompose and be eaten completely.

Some manure from herbivorous animals and pets can also make good food for worms, some of it may be added directly.  

Eggshells are also useful to add every now and then to the wormery. Worms have a gizzard and hard material like eggshells, ideally ground, help them to break down food. It’s also beneficial to balance the ph level in case you added too much food too quickly. 

What NOT to Feed?

Citrus fruits and peels and onion and garlic are best to be avoided. Citrus fruit is too acidic when fresh.

Onions will go eventually and wouldn’t do any harm to your worms. However, the smell of a rotting onion is awful while it’s in the rotting-getting-ready-to-be-eaten-by-worms stage and would be better of in an outside compost heap or, you could add a bokashi bin as a prior treatment stage.

Do not add animal based food like meat, fish, oil, fat and dairy products to the bin. If you are interested in making use of these leftovers check out Bokashi fermenting here. This process is a possible way to produce organic matter worms can feed on. 

How does Vermicomposting Work?

We have looked at how a wormery works but how is vermicomposting different from a traditional composting? Vermicomposting is a combination of conventional composting and composting with worms. 

In conventional composting organic matter decays mainly due to microbial activities. Although, in reality in most garden compost heaps or compost bins reality there’ll be various critters at work breaking down leaves, wood, kitchen scraps. More often than not there might also be a couple of worms somewhere in the pile, especially if the compost heap has soil contact at the bottom.

Vermicomposting purposefully employs surface dwelling worms like red wigglers or European nightcrawlers to break down and digest usually plant based dead and decaying matter.

Worms aid and speed up the composting process. Worms also add more variety of microbes to the compost when digesting it. 

This increased microbial activity continues after digesting and pooing it out. In fact, worms eat those casts again and that way add more microbes, too.

The result is a compost with reduced levels of contaminants, rich in water-soluble nutrients. All of this makes it a great organic fertilizer and soil conditioner. Many experiments, tests and measurements have shown how plants thrive and are less prone to plant-diseases in soil that has vermicasts added. 

How to Use Vermicompost?

Once the worms have digested the food you will have some earthy smelling, crumbly, moist vermicompost. Even though you can’t see it it’s full of microbial life and nutrition for plants.

Bear in mind that this is a fertilizer and soil conditioner. For best results add only up to one fifth to potted plants. You could also work some into the top soil around plants outdoors.

Another application is compost tea where vermicompost is soaked in water which is then used to water plant roots or sprayed directly onto leaves.

What Type of Wormery is Best?

There are different designs of wormeries for various amounts of organic matter, purpose and personal preference. Some are used primarily to compost kitchen waste, others use them to breed worms for fishing or as pet food for example for axolotls.

However, they all need to provide a damp environment where the worms can settle in, feed and reproduce. 

Worm Composters for Homes, Balconies and Small Backyards

These wormeries should ideally fulfill the following criteria. 

They need to

  • cope with the amount of kitchen scraps generated in the household
  • should be easy to access
  • cope with and keep constant humidity inside
  • be easy to access to add food also to harvest the worm castings when ready.

Cover – The wormery itself doesn’t have to have a tight fitting lid to make it work. However, worms like to live and eat under dark and damp covers. A layer of cardboard or  a layer of fabric will keep conditions damp and dark enough for the light-sensitive worms. Worms also like a layer of bubble-wrap if the bin is inside a cupboard, shed or garage where there is no light most of the time. 

An additional function of the cover is to keep elements and critters and rodents out. Therefore a properly fitted cover is useful.

Optional requirements 

Drainage – some owners are very good at monitoring and regulating humidity levels in the wormery with dry materials like shredded paper or cardboard so that there is no excess fluid at the bottom of the bin. If you are rather a set and forget person a wormery with a drainage tap would be better. 

Stackable Flow Through Worming Composter

The majority of commercially available wormeries have several trays that can be stacked on top of each other and a sump and drain tap at the bottom. 

To start such a wormery bedding and worms are placed in the bottom tray. Bit by bit organic material is added. When full the next ray is placed on top.The trays have a sieve like bottom allowing worms to crawl up and down as they want. 

By the time the top tray is full the material in lowest one has turned into compost and worm castings. At this point the worm castings can be harvested. This is likely to take around 6 months. 

These types of wormeries are easy to maintain, especially so with the drainage incorporated. That way you don’t have to worry that the system gets waterlogged.

Continuous Flow Through Worming Composter

This type of wormery has just one, usually tapered compartment. It is filled from the top. Worm castings can be harvested from the bottom. There is also a drainage tap for excess fluids.

A continuous flow through composter is probably the most hands-off design for private use. Food goes in on the top. Worm castings out at the bottom. All of that takes only a few seconds. 

They are cleverly designed to make use of the worms’ natural behaviour of moving towards higher grounds where food is plenty and less compacted than in lower levels. 

Also, by the time organic scraps have gone from decaying and being eaten and being turned into worm poop (worm castings) and moved to the bottom of the composter any worm cocoons will have hatched and no new ones laid in the lower level. 

The big advantage is that the vermicast harvested at the bottom is full of microbial activity but without worms or cocoons. This makes harvesting very easy, indeed.

These types of composters are pricier and tend to have a slightly larger footprint. They are more suitable for the outside, a shed or garage.

Shallow Wormery boxes – DIY

Since composting worms only need damp bedding, food and a cover material for the system to work it is fairly easy to create a wormery out of a plastic or wooden box. 

The simplest design is just a plastic or wooden box with aeration holes on the top and perhaps a lid or at least a piece of cardboard or layer of fabric on top.

Experienced wormery users benefit from this low cost type. If you are a beginner you will have to monitor this more closely mainly to avoid excess liquid (leachate) which could turn this into a smelly unpleasant affair quite quickly. 

It will take the same amount of time for worm castings to be ready as in a stackable wormery. The box is either left until worms seem to have gone through all the food or if it’s fed continuously you will have to decide how you separate the castings from fresh food. 


There are plenty of wormery designs to choose from If you like the idea of turning your kitchen scraps and vegetable peels into nutrient rich compost either for your own plants or to give to a green thumbed friend.

Commercially flow through wormeries are easy to set up and maintain. They also tend to look better than a DIY built one made out of buckets, waste bins and such. 

Now that you know how a wormery works and just want to have a go and see whether vermicomposting is for you, setting up a tray or simple wormery bin is a cheap and cheerful way to find out.

Related: How to breed worms fast at optimum rate?