FAQ 's

Frequently Asked Questions

What is the benefit of worm composting as opposed to 'ordinary' composting ?
('Ordinary' usually means putting food, cardboard and garden waste into a contained or open heap in the back garden)

When dealing with large amounts of food waste, the solution might be different from smaller situations.

In a small household without much or any garden space, a wormery can be very compact way of processing food waste. The compost and liquid feed that it produces can be used in planters.

In a slightly larger household with a garden, the food waste when mixed with cardboard and some of the finer garden waste forms a good rotting mix. It might be best to compost it all in a plastic dalek- type composter. If there is a rat problem it can be addressed by rat proofing with chicken wire. The coarser garden waste can rot down on a heap. (and on an aside; a heap of twiggy prunings can produce very good compost over several years, if you tunnel in at the bottom, as all the rotting leaves, seem to trickle down, and produce a beautiful fine potting compost. I have done this, with a heap of prunings that I added to each winter. After 8 years I was getting good compost at the bottom, and the size of the heap was constantly collapsing.)

But on a big scale it makes sense to separate garden waste from the food/cardboard, because of the rat proofing that the food/cardboard needs from the start. (when the rats move in, it is too late, as the whole operation is big, and it would take time to then rat proof*). It would be wasteful to rat proof garden waste. So the containers that are built for the food/cardboard should be for that alone. For the garden waste open containers will work best and be easier to construct. That is not to say that some fine garden waste could not be added to the wormery. But I advise extreme caution on this. Make sure everyone knows exactly what garden waste can go in it. Persistent weeds such as couch grass, bind weed, creeping buttercup etc should be rotted separately, e.g. in a barrel of water to kill them off.

* By the way there is an animal rights issue here. But not the one you might think. It is that, if you allow rats to reside in the composting food waste, and the time comes to turn it, or to dig it out, you may well, disturb and kill rat babies in nests. You will also remove the food source and home of a whole community of rats living there, who may then starve. It is kinder not to allow a rat population to build up in the first place. Admittedly, they may come and live in garden waste heaps, and that is hard to stop, as it would be crazy to rat proof every heap of sticks etc. But the access to food is the one thing that will make their population rocket, so by rat proofing your food composting operation you will remove the bulk of the problem. I think. !

Is it faster than other forms of composting ?
It is not faster than hot composting, probably slightly slower. But it can be faster than other cool composting, because the worms move material around and help to aerate and break it down.

What are the advantages of wormeries over hot composting ?
Wormeries can use lower levels of technology and less energy. Large scale hot composting systems seem to involve metal containers, and machinery to turn it. A wormery can be made of stout wood, and no more. It takes up more space however, as a large surface area is needed for the composting material to be aerated enough.

Wormeries do not need turning like hot composting systems. However, sometimes, the food and cardboard going into a wormery can generate heat (from thermophilic bacteria), and it gets too hot for the worms, especially in the summer, and kills them. Therefore sometimes, a turned heap is managed then fed to the wormery to finish it off, or a wormery can be designed so it has different levels with sloping ramps (see the design at Stapleton Road station). This is intended to allow for the heat generation (which in the winter is of course beneficial) to be separate from the worms, which can reside on the floor below, and receive the cooler, rotting material as it slides down. This design with sloping floors is being piloted and has yet to prove itself.....

How long does it take to convert waste into compost ?
This depends on the air temperature and the number of worms, but if loads of worms are present and it is the optimal temperature (15 - 25 C) then it should be in a few weeks.

How is this different from my compost heap, because that has loads of worms in it ?A good compost heap often has composting worms in it. A wormery is simply a compost system that makes sure they are present in great numbers. It is not that different at all. It still needs all the other composting processes: the fungi, the bacteria, the invertebrates that break material down. The worms are simply encouraged as they speed it up and ingest all the material and convert it into worm casts. And the way it is managed is a bit more precise to make it faster. So garden waste is not put into it, and the optimal conditions for worms are maintained, such as being moist but not water logged.

Isn't it cruel to contain worms in this way?
The problem some people see is that the earthworms are contained whereas a garden heap, or bin, can allow free access for worms to come and go. In the keeping of any creature we bear a responsibility for its welfare, therefore, it is important that they are kept in the right conditions of temperature, moisture, acidity and aeration. It is cruel to allow these conditions to get bad for them, as they can then die. But the point is that there would not be anywhere for them to go, unless they were in a particular habitat surrounded by piles of juicy rotting leaves, logs and stones, and even then the wild habitat would not support the same numbers of red compost worms. So it is not really an issue of whether they can migrate or not. In the high density organic environment of the compost bin, a much denser population of worms is created than exists in the natural habitat. They are found under logs, stones, in leaves and cowpats but in much lower numbers than in compost. The problem is that when compost is dug from a compost heap or bin, with all the composting earthworms, and other organisms in it, which cause that composting to happen, they are placed in the soil of the garden where the conditions are different, and there is a dieing off of a proportion of those organisms. Composting unfortunately, creates and generates a whole host of creatures which then have to fend for themselves when they are placed out in the soil, which is drier, and will have a reduced level of organic matter, as it rots down. Our interaction with the planet affects the habitat of other creatures, and in organic food growing, we create lots of habitats so that there is a diversity of species, which benefits our growing. But individuals of those species will at times find their habitat being moved and changed. We sadly cannot pick all the woodlice, pot worms, fruit flies or red compost worms out, and put them back where they are happiest. But this awareness of our effect on the other creatures, can only help us to reduce our impact, to acknowledge them, and their role in our own survival. And it shows us the need to leave plenty of wild habitat around our gardens, and wilderness areas of the planet untouched by ourselves.

(This is very longwinded.....sorry.)