How to make compost

All flowers, plants and trees get the majority of the nutrients that keep them alive and in bloom from the soil in which they are planted, so starting a compost heap at home is a great way to produce quality plant food for free. A compost also greatly reducing the amount of waste you send to landfill – Almost 50% of the contents of the average dustbin could be used effectively for compost.

In this guide we'll take you through how to start a compost heap and what you should, and shouldn't, include to keep your plants thriving.

How to make compost

There's no trick to it, you just provide the ingredients and let nature do the rest. The rich, dark and crumbly end product will be full of good nutrients that can work wonders on your garden.

Getting Started

Most people prefer to use a compost bin. This will prevent any animals from getting into your heap and stop any bad smells emanating from it; whilst also retaining the warmth and moisture that's necessary for good compost and allowing good air circulation. A compost heap can also be started on the bare earth and kept covered with a tarp, this way worms will be able to get in and aerate the pile, helping the materials to breakdown faster.

What to Compost

Knowing which materials to compost can be a little complicated, too much of the wrong things could end up damaging your plants. The following table should give you a pretty good idea of what's in your bin that could be feeding the plants.

 

Waste Material Value Tips
Waste water/drinks Neutral Your compost heap should be kept nice and moist at all times, topping up with water every now and then can help with this; although with too much water you'll end up creating a swamp.
Cardboard Carbon Small quantities of cardboard can be good for a compost heap, if you have a large amount; however, it's best to recycle rather than compost.
Corn cobs or stalks Carbon These are best when shredded, as they'll break down a lot faster.
Coffee grounds and filters Nitrogen Great treat for the worms!
Fruit and fruit peel Nitrogen Fleshy peel like banana peel can take longer to decompose, bury in the middle.
Tumble dryer lint Carbon Great for moisture levels.
Egg shells Calcium Crush shells as they break down slowly. Great obstacle course to keep the slugs and snails away.
Hair Nitrogen Sprinkle evenly across pile.
Dry or Green Leaves Carbon Avoid using diseased plants or bushes.
Manure (chicken, cow, goat, horse, pig, rabbit, sheep) Nitrogen Great for speeding up the composting process.
Newspaper Carbon Similar to cardboard, only use in small broken down amounts. Consider recycling large amounts.
Pine needles and cones Carbon Slow break down and acidic finish, use moderately.
Sawdust and wood shavings Carbon Very high carbon content so avoid using lots unless you can balance with a lot of nitrogen. Use untreated wood only.
Vegetables Nitrogen Bury deep to speed up break down.
 

What not to Compost

Most types of kitchen and garden waste are fine to throw on the compost heap, however; there are a few things you'll definitely want to avoid.

Waste Material Effect
Ashes from coal or charcoal Coal ash is an alkali and can throw off your compost's PH balance. Some brands of charcoal contain paraffin, wax or other chemicals you wouldn't want in your garden, as well as the grease that dripped down from your barbecue.
Dairy (cheese, milk, yoghurt) These won't add much to the compost but will make it more attractive to pests.
Diseased plants If you use diseased material for composting you risk spreading that disease further around your garden.
Fish scraps and bones Builds unpleasant smells and attractive to unwanted rodents.
Lemons and limes While they are OK in small amounts, citrus fruits are highly acidic and may stop the composting process.
Manure (bird, cat, dog) May contain diseased organisms.
Meat, fat, grease, oil or bones. These are very slow to decompose and don't contribute very much to the soil quality.
Treated wood The varnish or oils used to treat wood often contain chemicals which aren't much good for your soil; even naturally treated wood is likely to be too strong an alkali to benefit your composting.
Weeds Weeds tend to be highly persistent species that could come back even when removed and placed in compost, best to destroy them yourself or put in the bin.

Speeding things up

Ordinarily, compost can take up to 9 months to break down to usable level, and even longer if you have a lot of fleshy fruit peels or other large items in there. Turning over the compost with a pitch fork every couple of weeks will help the process along, we also have a range of compost accelerator products available which add extra microbes and enzymes to the mix, encouraging faster breakdown.

What not to Compost