How Do I Look After My Worm Farm?

Author: deanne Raccanello  


Worms can eat up to half their own body weight daily, depending on food source and can double their population every few months.

Start your worm farm with at least 2000 worms (½kg) and they will eat approximately 250g of food waste per day.

Once the numbers have increased, you will be able to feed the worms more. Worms regulate their population to suit the amount of available space and food, and will stop breeding when no food source is available or they are overcrowded.

Once the compost worms have adapted to a new food source, worms will ‘eat’ at a much faster rate. Breaking down kitchen scraps in a blender, food processor or with a couple of minutes in the microwave will assist the worms to convert more scraps into fertiliser.

Avoid meat and the onion and citrus family of foods, as well as too much acidic food such as tomatoes. These will not be converted and may therefore cause an odour problem or ‘sour bedding’.

A handful of Ag lime each week helps to control the pH in your Worm Farm. Worms and vermicast (worm manure) do not smell. If your worm farm has a bad smell, you are most likely giving the worms more food than they can cope with.

Remember to keep food covered with a piece of old carpet, underlay or hessian bag. Worms are light sensitive and will not come up to the surface through the day if you leave the food uncovered. 

When using any kind of manure in your Worm Farm, remember that vermicides used to kill intestinal worms in animals may also kill your compost worms. Dog and cat worming preparations are usually very mild today and generally no problem, but you can test the first time you use the manure by placing half a dozen worms in a container with the manure and see if they survive 24 hours. Worms do love animal manure, so it’s worth the effort to persevere.

Green garden waste may heat up in your Worm Farm, so use carefully. A layer of grass clippings from time to time will add some fibrous material, which is good for its overall condition.

It is also a good idea to aerate the top few inches of the Worm Farm once a week with a small garden fork, to help the worms work more easily through the food. It is also essential to aerate the Worm Farm after a heavy watering to avoid muddy anaerobic conditions. Moisture and oxygen are critical for the wellbeing of the worms and the system.

When going on holiday, extra food is best in larger pieces and well covered with a layer of wet, brown grass clippings. Water well and aerate before leaving, trying to leave some ‘wet’ foods like melon and lettuce in the Worm Farm. It should be quite safe for a fortnight in a cool shady spot.

Compost Worms will tolerate a wide temperature range, with the worms having a comfort zone similar to ours. In high temperatures, make sure the Worm Farm is in a shady spot and water lightly morning and night if necessary. In cold and frosty times, daytime sun is good, and use a layer of green grass clippings or fresh manure over the top of the food for warmth.

If constant rain is forecast you may notice your worms gathering at the top of the Worm Farm. Worms are sensitive to pressure changes in the weather. In nature, this takes them out of the soil to stop them from drowning. Put the worms back down in the bedding and cover with a layer of food or grass clippings, then cover until the rain eases.

Many organisms that may appear in your Worm Farm are beneficial to the breakdown of organic material. These may include tiny mites or soldier fly larvae (a large greyish armadillo looking maggot!) Overloads of these inhabitants can suggest acidic conditions. Have you been adding your handful of lime weekly and not overfeeding? They will not hurt the compost worms and are only a pest to you as they are demolishing the food rather than converting it to rich organic fertiliser as your worms do. A piece of bread soaked in milk helps to attract the maggots so they can be easily removed.