Vermicomposting – worm compost for the household and garden. (flyer)

The biggest advantage of this type of composting is that only small spaces are needed. This means that the composting can be done in small bins and other small boxes, also on the terrace, balcony, in the cellar etc.

What is vermicomposting?

It is a composting process using worms to create an end product called vermicompost. This is based on the ability of the worms to transform in their digestive system organic matter which then turns into nutrient-rich compost.

Which worms are suitable?

Commonly used are Red Wigglers (Eisenia foetida). These worms live in the top layer of rotting vegetation, in piles of compost and manure. Other suitable worms are Eisenia Andrei, Lumbricus rubellus, which are available from farmers (ads in gardening magazines) under a variety of names (e.g. Californian worms). You can recognise Red Wigglers by their colour, which is stripy, with yellow and dark red-brown stripes.

The ideal temperature for them is between 18 – 25 ˚C. This is the reason why they are going to be happy in any household. However, the most common earthworms would not be that happy, because they require different living conditions. Worms dislike sun, dryness, low and high temperatures. They need to be protected from moles, birds and voles, which are their natural predators.

Composting bin

You need a suitable container made of strong and opaque material (worms hate light) with a tight fitting lid (protects from drying out and fruit flies) and with some holes to provide aeration and also some holes in the bottom so the excess moisture can escape. It is important to maintain the size of the box at a ratio of 1 : 2 : 3 (as seen in the picture), because the activity of the worms is dependent on the area of the surface. The bin can be made from wood or plastic. Wood has good isolation qualities, but it will slowly start rotting.

Plastic bins are more resistant and easier to clean. The bin can be placed in a hall, on a balcony (when it is not freezing), in a garage, workshop or a cellar. It should not be placed in direct sunlight (to prevent overheating and drying out of the compost). Place a tray underneath to capture excess liquid. If you want to do the composting directly in the garden without any bin, put some mesh at the bottom of the pile to prevent moles and voles from accessing the worms. The size of the unit should be geared to your household's production of kitchen scraps; on average for 1 kg of waste you will need 0.2 m².

Bedding

This holds moisture and will allow worms to burrow in. You can use soil, old leaves, grass, hay, wood shavings or wet torn newspaper. It is very important to have sufficient moisture because the worms are very sensitive to it.

What and how to feed?

Suitable worm foods are vegetable scraps (vegetable and fruit peel, stale bread, teabags, coffee grounds, crushed egg shells, grass, leaves, wood shavings, saw dust…).

Unsuitable foods are bones, meat, fish, dairy products, greasy food leftovers. You need to avoid food with high salt content (the highest concentration for worms is 0.5 %) and also food scraps that could be contaminated by chemicals (e.g. citrus fruit).

Bury the food scraps in different places in the bedding, in a way that they stay covered. Food waste that sticks out of the bedding or is too big can start smelling or get mouldy. These bits need to be removed from the bin.

How many worms do you need?

The amount of worms needed will depend on the quantity of kitchen waste you generate. If you produce daily on average 0.25 kg of kitchen waste, you will need 0.5 – 0.75 kg of worms. The worm population easily adjusts to conditions in the worm box according to the feed supply and bedding. In this way they regulate their population in a natural way. If you are a composting beginner, it is better to start slowly, with the smaller space, little worm population and fewer feeds. Once you gain confidence, you can expand to compost on a scale suitable for the whole household.

How to harvest the compost?

If you need to use the vermicompost, push the decomposed material to one side of the bin and fill the other side with new, moist bedding and kitchen scraps. The worms will gradually migrate into the new pile – a new source of food, and you can remove newly made compost from the compost bin.

When handling the vermicompost it is better to use blunt tools, which will prevent worms from unnecessary injury.

How to use vermicompost?

You can use the vermicompost as it is, either adding it to the top soil, or to the roots of the plants, or mix with soil in the following ratio: 1 part of compost, 3 parts of soil.

The vermicompost can be used as fertilizer for flowers and vegetables during the vegetation period. The fertilizer can be made with 60g vermicompost and 1 litre of water. After thorough stirring, leave to stand for 24 hours and the final product can be used for watering plants.

A similar solution can be used for hydroponic gardening – 10 g of vermicompost mixed with 1 litre of water. This solution needs to be replaced every 20 days.

In fruit growing, vermicompost has been very successful with tree transplanting. Adding the vermicompost in the hole for the roots of the tree lowers the risk of the tree dying.

Most common problems:

Problem	Solution
Mould on the waste	The feed is not completely covered with bedding. Remove mouldy parts and cover well with bedding.
Fruit flies	Compost not covered very well.
Unpleasant odors	Not suitable composition, moisture or too much composting matter – add drier material/feed, decrease amount of feeds.
Worms are dying or escaping the box	Unsuitable living conditions – temperature, moisture, pH, unsuitable or insufficient feeds, box too small. Remove the castings (it is toxic for the worms), adjust moisture, feeds, the size of the box.