Friday, 14 December 2007

Where there’s muck: a guide to composting

Turning your waste into compost is easy, and your plants will thank you for it

If you have not discovered the joys of making compost, now is the time to try – not least to avoid unpleasant smells emanating from your wheelie bin in hot weather, especially if the council is cutting back refuse collections to once a fortnight. Not only will you be taking a significant eco-friendly measure, you will be doing your garden a great favour. Compost isn’t called “gardener’s gold” for nothing: digging it in improves the texture of the soil, while adding a layer on top and using it as a mulch (aim for a couple of inches) helps fend off weeds. It also boosts the level of friendly bacteria, making for healthier plants.

Do not be put off by earlier composting failures. If they resulted in a slimy, foul-smelling mess, you were probably using one of the Dalek-shaped plastic compost bins that local councils offer for less than a tenner. Lured into buying them by the promise of “no turning necessary”, novices fill them with grass cuttings and kitchen waste, but the result is often a sticky sludge with a pong.

Making compost isn’t difficult, however, if you understand some of the science involved in its creation. Most of what we are likely to throw into a compost heap – peelings from fruit and vegetables, grass clippings and weeds – is “green” waste, which has a high water content and is rich in nitrogen. Used alone, particularly in one of those Dalek containers, it sticks together and doesn’t allow air, which is crucial for decomposition, to enter the pile.

To stop a heap from putrefying, you must layer the “green” material with dryer “brown” material, which is high in carbon. “Browns” include dried leaves, egg boxes, scrunched-up newspaper and the cardboard core of loo rolls. Think of the compost heap as a cake and alternate layers of green and brown, each between 2in and 4in thick. Fill your Dalek composter like this and it will work fine.

Admittedly, vermin, including rats, and even wasps, will be drawn to a compost pile – but, given the benefits, this is no reason not to have one. Make it less attractive to pests by turning and tending the pile regularly, and by keeping it covered and hot so they won’t be able to nest in it. And never add meat scraps.

The low-maintenance pile: if you are happy to make compost slowly, in return for not bothering too much with it, sit the container directly on the earth, so earthworms can rise and break down the pile of waste. Start with some twiggy material at the bottom, which will aerate it, then add alternate layers of “brown” and “green” material, building them up as you go along. Sprinkle soil over the layers (two or three handfuls is enough) to introduce extra bacteria and help the matter to decompose. Or, if you have a friend with an existing pile, ask them to donate a bucket of compost to start you off.

A good alternative is to get a garden-centre bag of manure and throw a few handfuls on every so often. If the pile is dry, sprinkle it with water when you’ve finished adding a layer. Some people like to use a compost accelerator such as Garotta (available from garden centres); others keep a box of lime handy, to stop the pile from becoming too acidic and smelly. But neither is strictly necessary. A pile like this can be made in a plastic compost bin, covered and left to do its own thing. The rate of decomposition will vary, but you should end up with usable compost within a year.

The fast stuff: if you generate lots of kitchen and garden waste, or want to make compost quickly, then you will need two compost bins. Build up a pile in one as explained above, let it settle for a week or two, then turn it into the second bin. Turning the pile regularly and introducing more air causes matter to heat up and break down more quickly, decomposing in four months or less. (Don’t regard turning compost as a chore, either; it can be surprisingly therapeutic and add a bit of calm to your life.) Warmth is as important as air to the process, so keep the pile covered.

Wormeries: this is a good solution for a small household that doesn’t generate much waste. With your wormery comes a set of live worms and bedding for them to start out in. Place small amounts of cut-up, uncooked kitchen waste on top of this – the amount of food is increased as the colony grows. The worms eat their way up through the first layer of food and into the next, leaving the compost behind. The amount created is small, but it produces a rich liquid called leachate, which can be tapped off at the bottom, then diluted and used as a plant food.

Bokashi buckets: bokashi is the Japanese word for fermented organic matter, and this system is unusual because it involves both cooked and uncooked kitchen waste. Read the instructions carefully to see what you can and can’t add. It requires two buckets made with a special plastic impregnated with effective micro-organisms – friendly bacteria, essentially. These start the breakdown process and work to eliminate odour.

Put a layer of food a couple of inches thick in the bucket, then sprinkle on a layer of special bran, again impregnated with those micro-organisms, followed by another layer of food. Continue alternating the layers until the bucket is full, then leave it for 10-14 days while you start a new one. The first bucket can be drained periodically of liquid, which is used to neutralise bacteria in drains or as a plant food.

Once the bokashi has been made, it can be added to your standard compost heap. You can also bury it in the garden and plant over it; it is ideal for hungry crops such as runner beans or even dahlias. The kit isn’t cheap (about £80 for two 18-litre buckets, the biggest available), but the system is extremely useful for reducing the smelly element of a kitchen bin. Larger families may need to buy another bucket to take all the waste generated.

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1 comment:

Karen Dowell said...

Great article on composting. It's worth noting that both wormery and bokashi composting are absolutely ideal if you only have limited space available.

Have a great Christmas.

Karen, Wiggly Wigglers