The joy of making your own compost
An increasing number of people are turning to composting over concerns about the amount of waste going into landfills, reports Deb Tapp.
Wellington’s Sustainability Trust is constantly inundated with questions about composting and is running additional workshops to appease that need, says sustainability educator Caroline Arrowsmith.
“We get tonnes of questions about what you can and can’t put in your compost, and we’re putting on more workshops on the likes of rat-proofing compost, because people are concerned about what’s going into landfill.
“It’s becoming more relevant now because people are realising that throwing food waste into the landfill is wasting an opportunity to put what could be good compost back into their gardens.”
For those who don’t already compost it’s not too late, nor too hard to get started, says Caroline.
You can buy a compost bin or simply make your own out of the likes of old pallets – you don’t even need a bin though it does keep things tidier and contained.
Position your bin in a discreet corner of your garden and sizewise, about 1mx1mx1m is recommended.
Start off with a layer of crisscrossed sticks on bare soil or grass, which Caroline says will help with drainage and aeration.
Then begin to add a mix of garden, food waste, cardboard and paper.
“Add alternate layers of green matter, which is nitrogen-rich, wet, often green or colourful and smelly, and brown matter, which is carbon-rich, dry, often brittle or dusty,” advises Caroline.
Then add more material as you produce it, aiming for half green and half brown volume-wise.
Green, nitrogen-rich materials include food scraps, manure, fresh grass clippings, weeds without seeds, seaweed, tea leaves and coffee grounds.
Avoid meat and fish, invasive weeds, diseased plants and cat or dog faeces.
Brown, carbon-rich material includes torn up newspaper, cardboard, chopped tree prunings, dry leaves and bark, untreated sawdust and wood ash, twigs and sticks.
Glossy magazines, non-organics, tin, glass and plastics, bamboo, flax and cabbage tree leaves are all nonos.
To maintain moisture levels, cover your heap with either a plastic lid, carpet or tarpaulin.
Compost should be damp, not sludgy, says Caroline.
“The water content of your compost should feel like a wrungout sponge, but if it’s too dry sprinkle it with water or add more green, nitrogen-rich materials.”
If it’s too wet, Caroline says it’s a sign that your compost pile doesn’t have enough carbon-rich material, so add some straw, twigs or newspaper.
Smelly compost also usually means either a lack of brown, carbon-rich materials or air – just add more brown materials and turn your compost more regularly to aerate.
You can turn your heap with a fork to help aerate it and speed up the process, or poke holes through it, says Caroline.
Compost can be ready as soon as six to eight weeks if it is well aerated, she says.
Perfectly decomposed compost is a fine dark brown mixture, which Caroline says will look like good, crumbly chocolate cake and smell like nothing but clean earth.
When it comes to composting, one of the biggest problems to contend with are rats, but there are a few tricks to keep them at bay.
“Add grass clippings and turn your compost to increase the heat and discourage rodents,” says Caroline.
“Placing carbon, or brown materials on top as well as through your compost will discourage tempting smells, but whatever you do, don’t throw in bones or meat!”
Wire mesh under and around the bin gives you an extra layer of protection, says Caroline.
While the Sustainability Trust is helping to educate people on all aspects of composting, there are still some common queries that arise.
“There are still a few misconceptions out there,” says Caroline.
“One is that compost needs to be rotated, a lot of people don’t realise it needs a shake-up, you can’t leave it there to rot because it won’t do an awful lot, except get smelly.
“Some questions are also around whether or not you can compost compostable packaging, and what the difference between biodegradable and compostable is.
“Biodegradable products contain synthetic materials which means they never fully break down, and compostable products are 100 percent natural, which means they will break down in a compost.
“Things labelled as ‘home compostable’ will break down in your compost, but other compostable products require commercial systems to get the heat necessary to process them.”
The biggest misconception of all is that food waste going to the landfill will break down anyway, says Caroline.
“People still put food waste in their skip bins and rubbish bags destined for the landfill, thinking that once it gets tipped out it’ll break down, but it won’t because it needs aeration.
It will sit in the landfill for a long time producing methane, a greenhouse gas far more potent than carbon dioxide and devastating for the climate.”
Having your own compost bin will drastically reduce landfill waste, by around 44 percent in fact,” says Caroline.
“If everyone had their own compost bins or access to a community compost, we could stop sending valuable organic waste to landfill and instead use it to grow soil, food, and healthier communities.”