Composting With Worms
28 January 2013
No matter how hard we try, it is impossible to eliminate kitchen waste altogether. For example, potato peelings, the scabby outer leaves of a cauliflower, or some fruit that has gone rotten.
Normal composting techniques will deal with this waste quite satisfactorily, but during the summer months your traditional compost heap is likely to become overloaded with grass and hedge clippings, weeds and dead flowers. Alternatively, you may not have enough room for a compost heap but still want to get rid of your kitchen waste.
A very compact way of increasing your composting capacity during the summer months is to use worms. Worm composters are extremely easy to make, require very little maintenance, and process food waste incredibly quickly and efficiently.
I have two worm composters which are more than adequate to deal with all of the family’s food waste from about May to October.
During the winter months, the cold weather slows the worms down to the point that they do not perform any useful purpose, and it is better to rely on your traditional composter during this time.
Building a Worm Composter
To make a simple worm composter you will need a recycling bin of approximately 65 litres (18 gallons) capacity with a lid. You will also need a short piece of timber, 4 bricks and a small sheet of plastic or a plastic tray.
The base of the bin is drilled all over with 10mm holes for drainage and then the bottom is filled with 100 to 150mm (4 to 6 inches) of well rotted compost from your compost heap. Alternatively, you can use some peat free compost from your local garden centre.
Then the worms are added. The worms used in composters are not ordinary earth worms, and you will have to either order them in quantity from a supplier, or buy some from your local fishing shop. If you buy your worms from a fishing shop, ask for 'live brandlings'. A quarter kilo (˝ lb) should be sufficient as a start. Sprinkle everything with a watering can so that it is moist but not waterlogged and add a layer of vegetable peelings.
Lay an old newspaper over the top, and then a thin sheet of plastic over the top of that. For the plastic sheet, I use cheap plastic trays from the local pound shop. Make sure the plastic sheet/tray is loose fitting against the walls of the bin to allow ventilation, aiming for about 25mm all the way round, between the edge of the plastic sheet and the walls of the bin.
The bin is stood on 4 bricks, and the lid is added to prevent the bin becoming waterlogged when it rains.
Prop the lid open with a piece of timber to provide ventilation. Propping the lid is important because the worms need to sense a temperature/humidity transition as they climb up the inside walls of the bin or they will continue to climb out and eventually escape.
Position the composter in the shade, and near the house for convenient access. Make sure it is not exposed to the midday sun or you risk casseroling the worms!
Maintenance of your Composter.
Although the plastic bin and plastic sheet will suppress evaporation, it will be necessary to add water from time to time in the summer months. Check that the composter is moist when you add your vegetable waste. The composter can be watered naturally if you remove the main lid when rain is forecast.
Most vegetable kitchen waste can be fed to your worms. The only thing they are not too keen on is citrus fruit. Probably because of the citric acid. Also, don't put heavily salted waste into the bin. The osmotic effects of salt in the compost is not good for the worms. You can also add (in moderation), shredded paper, eggshells and teabags. Do not under any circumstances add meat or fat.
Feed the worms at a rate they can manage. At first, this won't be much as they will need time to multiply before they can process large amounts of waste.
In the wintertime you need to protect the worms from the worst of the frost. To date, I have found it sufficient to put a thick layer of shredded paper under the plastic sheet as surface insulation. However, if it gets really cold, I would recommend wrapping the walls of the composter with a few layers of bubble wrap.
Once you have one composter going well, you can split the worm colony into two and double your waste food processing capacity.
You will find that worm compost is very dense and compact. I would not recommend adding it directly to your garden. Instead, when a bin gets full, remove the top layers of vegetable waste and worms and tip the lower layer onto your conventional compost heap to give a less potent, more plant friendly blend.
Put the worm layer and vegetable matter back in the bin and you are ready for business again.
My composters have been working well for about 4 or five years now with no major problems. I would recommend the system to anyone.
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