Get composting

Turn kitchen waste into “black gold” but only if you follow the rules on what to compost and what to avoid

A couple of months ago, in a moment of gardening gluttony, I used up my entire store of homemade garden compost – a dozen large barrows of sweet-smelling, crumbly “black gold” that went straight onto the polytunnel beds in an effort to improve the heavy clay soil. Which it quickly did; if those plants could dance, they’d be doing the rumba.

The downside of such beneficence is that all the other areas of the garden equally in need of this nutrient-rich, weed-suppressing homemade mulch will now have to wait until the next batch is ready. Meanwhile, I’ve been doing everything I can to speed up the process, including regularly turning all four compost heaps and adding liquid doses of the herbal-based activator known as QR (qrcompostingsolutions.co.uk), developed by the Northern Irish gardener Maye Bruce back in the 1930s. Daily close examination of the bins tells me it’s working – I reckon I’ll have a fresh supply within a week or two.

But what I only recently discovered is that once the new EU regulations governing the disposal of household food waste come into force at the beginning of July, I mightn’t be the only person subjecting my compost bins to such careful scrutiny. According to S.I. No. 71/ 2013, from next month the roll-out of the brown or organics bin will be extended to all households living in towns with a population of more than 25,000 people, who will be obliged to either segregate their household food waste from non-bio-degradable materials or else subject it to a home composting process/ bring it to an authorised facility. By 2016, that regulation will apply to all population centres above 500.

It won't be enough to simply give the authorities your word that you home-compost. Given reasonable doubt, the regulation gives them the right to pay a home visit. So, along with the fact that so many tons of organic household waste needlessly goes to landfill and so many waste collection services operate on a pay-by-weight system, the phased introduction of these organic bins is another great reason for gardeners to get composting. If you're a novice, don't worry if it seems a little daunting. In fact it's a relatively simple process as long as you follow a few golden rules.

The golden rules of composting
With or without human intervention, all organic waste slowly rots down. But the essence of a good composting system is that it transforms biodegradable materials into "black gold" as quickly, cleanly and as un-odoriferously as possible by providing the ideal conditions for the many different organisms – beneficial bacteria, fungi, nematodes, protozoa, rotifers, mites, springtails, earthworms, centipedes, ground beetles, ants, snails, slugs and many others – to collectively carry out the process of decomposition.

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Along with food (a balanced "diet" of carbon and nitrogen-rich organic matter is essential to any compost heap's food chain), these busy little critters need oxygen (lots of it), water (not too much of it) and warmth to carry out their important work. Otherwise anaerobic bacteria take over the heap, producing exactly the sorts of smelly compounds that have given compost bins a bad name. So keep your heap well-aerated by adding lots of carbon-rich roughage (cardboard, straw, dead leaves, shredded paper) as well as nitrogen-rich "greens" (peelings, rotten fruit, weed leaves, garden trimmings), turn it as regularly as possible and don't make it too small (no less than a cubic metre). A water-logged heap lacks oxygen, so cover it. Chop, shred and tear all materials into smallish pieces no bigger than 20 centimetres before adding them, which speeds/heats up the decomposition process. Ideally the heap should reach a temperature of 50 degrees Celsius for at least a week, after which most pathogens and weed seeds are killed, but in practice this can be difficult. For that reason I don't add diseased plant material or seedheads /roots of weeds. Grass clippings, I leave as a mulch on the lawn.

Not for the compost bin Cooked/uncooked meat, eggs, dairy products, as well as breads, biscuits, cakes, cereals, pasta and rice (while some gardeners do add cooked grains/pastas to their bin, these materials can attract rodents unless buried deeply in a hot compost heap), root systems or seed heads of any nasty weeds and diseased plant material.


That brown bin material
It goes to a composting site approved and validated by the Department of Agriculture and permitted/licensed by the relevant local authority/EPA. There it's batch-processed at high temperatures and in a way that kills off pathogens before being tested to a compost quality standard. Last year 80,000 tons of Irish household organic waste was processed in this way, resulting in 40,000 tons of nutrient-rich compost that was used in agriculture, by commercial landcapers and increasingly by home gardeners. See cre.ie for details and a map of local suppliers.


Different composting systems
For a downloadable guide to the different composting systems including wormeries and bokashi bins as well the materials suitable for composting, see StopFoodWaste's website (stopfoodwaste.ie). The same organisation also runs a series of free courses in master composting by American-born Craig Benton (also known as Dr Compost), the man who first devised the scheme.