Composting is a gift that keeps on giving, to the environment and to your garden. Justin Newcombe shares his top tips.
Just like baking, composting has a million and one recipes and the good news is they all work. Even if you feel like you're managing a sludge dump rather than a compost heap be assured, eventually you will produce something useful for your garden.
So what does the perfect compost look like? We're looking for a lively chocolate-coloured, crumbly substance, slightly greasy when you rub it between your fingers and that in its very final state will have few worms. The end product is the very end of the decomposition process.
Composting is almost as old as agriculture. Initially it started out as manuring, practised by the Persians and Greeks. But it was the Roman statesman Marcus Cato who wrote the first compost recipe. Marcus was a pragmatic man who calculated it was more cost effective to work a slave to death and buy a new one than provide him with superficial lifestyle choices like food. He saw compost-making as good business. Two thousand years later Sir Albert Howard developed the Indore method, on which most domestic methods are based today.
Most compost heaps are too dry but I often find the really smelly ones with a strong ammonia or acetic smell are just too wet. Wet heaps need more oxygen, so regular turning will improve the odour and the speed at which the compost is produced. Other problems also include infestations of insects and vermin but these too can be rectified with a decent recipe. Composting requires two main elements: greens (nitrogen) and browns (carbon). Other ingredients like water and a starter or activator which provide bacteria and oxygen are also essential. The classic recipe is two parts carbon to one part nitrogen but this depends on what the components are.
Turning your compost is important because it adds oxygen but it also allows you to rectify any problems your heap may be having. If the heap is too wet, more fine carbon like straw or dry leaves will help. If the carbon is too thick then more nitrogen ingredients may be added. Dry heaps can be watered; wet heaps, turned and covered. Environmentally composting is probably the single biggest hands-on difference you can make as it stops food waste from being put into landfills where it produces atmospherically destructive methane.
I've designed my garden with composting in mind. I like to use canna lilies and banana fronds as my green component as they release water evenly through the heap as they decompose. I also use a mixture of dry leaves and lawn clippings. As a starter I use compost from another bit of soil but you can also use comfrey leaves, sea weed and cow poo. Food scraps are basically a nitrogen component. If you store a carbon or brown component near your bin and do a 50/50 mix you should get good results.
Good greens and browns
Carbon/brown: Brown plant material such as dried leaves and straw (pea straw is great), twigs, cardboard and newspaper, paper towels and brown paper bags, saw dust (untreated), annual plants (after flowering).
Nitrogen/green: Lawn clippings (but take it easy, mix up with brown leaves), weeds, big green leaves such as from bananas or cannas, kitchen scraps (but not meat) and any annual plant before it flowers.
Justin's never-fail compost recipe
1 Place a 100mm layer of nitrogen materials into the bottom of the bin and water.
2 Place a 100mm layer of brown or carbon material into the bin and water.
3 Place a 20-30mm layer of activator layer into the bin and water. I use soil or compost dregs you usually find in a compost area.
4 Repeat this until the bin is full.
5 This method works best with larger bins such as those made from pallets and is excellent for processing large amounts of materials.