A Step-by-Step guide to Worm farming

Why farm with earthworms?

Worm farms are a great way to recycle your kitchen waste and food scraps into one of the best garden fertilizers available!

Worm farms are in fact worm composting systems, or more correctly, vermicomposting systems, and earthworms are one of the fastest composters there are.

It’s very easy to maintain a worm farm, it takes very little time and effort, and you can set up worm farms in the smallest of spaces, such as balconies and courtyards.

In this article we’ll explain how to set up a worm farm and how to take care of it.

It’s a win-win for everyone!

With worm farming you allow thousands of red wriggler worms to consume your kitchen organic waste. You provide them with a home, bedding, moisture, food in the form of organic waste, and offer them protection from the elements. The worms break down the waste in less time and space than traditional composting methods and provide a superior end product in the form of nutrient-rich earthworm castings – that you can use to feed your plants.

Learn some worm farm lingo:

Vermicompost / earthworm castings:

Vermicompost or Earthworm castings are essentially worm manure – the end product of the decomposition of organic matter (fruit and veg scraps) that you feed your worms every day. Vermicompost is an excellent nutrient-rich organic fertilizer that is perfect for your plants and garden.

Worm tea:

Worm tea has many of the same properties as worm castings and is in fact richer in a number of nutrients, including calcium, magnesium and phosphate. Worm tea, like worm castings, is a great organic plant food and in addition is also a natural insect repellent.

The worm farm consists of just 3 main parts:

The collection / worm tea tray (bottom):

This is the tray with the tap attached. This is used as the base of your farm and its purpose is to collect all the liquids and condensation that drains through from the trays above. It comes with a tap - to harvest the worm tea.

The breeding trays (middle and top):

Which is the 2 trays with the holes in their bases. They are your worm’s new homes. The holes allow the worms to migrate or pass from one tray to another and to allow for efficient drainage. These two go on top of the collection tray.

The lid:

This is used to cover the top of your worm farm.

Getting started!

Follow these step-by-step instructions to setting up your worm farm:

Step 1:

Initially (phase 1) you will start with one (1) worm farm tray / bin – stacked on top of the collection / worm tea tray / bin. Start by ensuring that a layer of black cloth is at the bottom of this tray. The cloth will prevent your worms from falling into the collection tray.

Place your worm farm in a sheltered, well shaded spot in the garden – preferably close to the kitchen - that is not too hot or too cold. Your earthworms don’t like light and heat. Preferred temperatures are between 18 and 26 degrees. Keeping them in the kitchen or in your garage is not a problem.

Step 2:

Cover the cloth with some shredded, moistened newspaper (shredded into strips), making sure the bedding is fluffy (not packed down) to provide air for the worms. The tray should be 3/4 full of moistened newspaper strips.

Sprinkle just a few cups (3 – 4) of soil into the tray, which introduces beneficial microorganisms. Gritty soil particles also aid the worms' digestive process. Potting soil, or soil from outdoors is fine.

Place a full sheet of dry newspaper on top of the bedding. This will help maintain the moisture balance, keep any possible odors in the bin, and will keep it nice and dark for the light sensitive worms.

REMEMBER: you want the bedding material to be damp, not soaking wet.

(For a full list of bedding materials that can be used, see bottom)

Step 3:

You will need between 500 and 1000 red wriggler worms (not the common, ordinary garden earthworm type). Place these into the worm farm tray, and place lid on top.

Step 4:

Once you’ve emptied your worms into the worm farm tray, you can begin to feed them. They probably won’t eat much initially – as they’re still settling in.

A handful of food per day or every second day (approx. 50 grams) will suffice for the first few weeks.

(As the worms start reproducing and your worm population increases, you can increase the amount of food).

Bury food scraps in the worm farm tray. Lift up the bedding, add food scraps, then cover food with bedding. (the worms aren’t going to come to the surface to eat if there is light)

Step 5:

After a while, once the first worm farm tray is full of worm castings, put the second empty worm farm tray on top of it (remember to follow step 2 to prepare bedding in this tray as well) – making sure that the bottom of the empty tray touches the worm castings underneath.

From now on, feed your worms in the top bin and the worms will begin to move up through the holes into the top bin to get to the food.

Step 6:

Once all the worms have migrated to the top tray, remove the middle worm farm tray and empty out the worm castings.

Remove the black cloth from the now empty worm farm tray, follow step 2 to prepare bedding in this tray, and stack the tray on top of the other two trays.

Step 7:

The empty worm farm tray is now on top. Repeat the process by putting the food in the top tray and once all the worms have migrated to the top tray, it is time to empty out the castings and swop the worm farm trays once again.

Tending your worms:

Feeding your worms with good food sources is vital in raising healthy and reproductive worms.

Good food sources include fruit and vegetable scraps from the kitchen, as well as tea bags, crushed eggshells, old bread and even saw dust, paper, and cardboard.

Keep in mind that the smaller the pieces of scraps are, the easiest and quickest it will be for the worms to digest.

AVOID: Do not feed your worms: pineapple, onion, cooking oil, meat, bones, butter, dairy products, tomatoes, and manure of any kind. In addition to this, foods like citrus fruits have high acid content and increase the acidity of your worm farm, negatively affecting your worms.

Red wriggler worms can consume up to half their body weight in food per day and naturally, after a few months, once your worms have acclimatized to their new environment and your worm farm is in full swing, the worms will be consuming up to a kilogram of food per day. If you happen to notice your worm farm is filling up with rotting food, stop feeding them until it has disappeared.

Frequently asked questions: 

Q: How do I harvest my vermicompost / worm castings?

Harvesting your worm castings is a quick and easy task.

Once both worm farm trays are full of worm castings, simply remove the middle bin and empty out the castings. Then place the now empty worm farm tray on top and place the new food in it.

(Follow steps 5,6,7 – as described above)

Q: How do I use the worm castings in my garden?

Use it as a top dressing: fertilize existing plants with worm castings, no mixing required. Just sprinkle a handful right where the roots go into the ground. Then, the nutrients filter down with the water and feed the plant.

Use it to amend your soil: incorporate the castings into your potting mix.

Use it as a seed starting mix: give your seedlings a boost by adding earthworm castings to their diet from day one.

Make worm casting tea: gardens love a good dose of liquid fertilizer. Worm casting tea is sometimes called compost tea. It is made by steeping worm castings in water – just like you would a cup of tea. As the worm castings soak, beneficial microbes multiply, creating a tonic that quickly delivers nutrients to the plant. You can spray this tea directly on the roots and even on the plant leaves as protection from airborne diseases and infestation.  Mix 1 part worm castings and 3 parts water in a bucket. Let that mixture soak for 24 hours or more, stirring occasionally.

Q: How do I harvest my worm tea?

Worm tea is simply the liquid from the worm castings and drips and filters down through the holes in the bottom of the worm farm trays, ultimately collecting in the bottom (collection) tray.

Use the tap at the bottom of your collection tray to release this liquid.

It is important to remember that this liquid may be very concentrated and usually needs to be diluted before it can be applied to plants. Add water at a ratio of 10 parts water to 1 part worm juice until it becomes a light brown colour, similar to the colour of a weak cup of tea, and then it is diluted enough to apply.

Q: What can I use for bedding material?

Many different materials will work – compost, straw, shredded newspaper, peat moss, shredded cardboard, leaves, and even coir.

You can basically use anything that provides the worms a moist environment, has enough fluff to allow air to circulate, and that the worms can eventually eat and break down.

It’s recommended to fluff your bedding material about once a week – so the worms get enough air.

Avoid using domesticated animal manures (dog and cat) – as pathogens are a major concern.

More about the residents:

The worms you have in your worm farm are not soil dwelling worms. They are composting worms (Eisenia fetida). They live on fresh, decomposing organic matter, and do not burrow like night crawlers (the common earthworm in your garden soil).