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How to make compost

Overview

Home-made compost is a great soil conditioner and plant food. Good compost will take about six months to produce if you turn it regularly.

Monty's compost recipe

What should you put on your heap? The simple answer is anything that has lived. But I exclude all meat, fat and anything that has been cooked, as these will attract vermin. I also avoid citrus remains because they are slow to rot and very acidic, which reduces worm activity.

Very few plants contain the right balance of nitrogen and carbon on their own to make perfect compost. Most piles have too much nitrogen, especially if the main source is from grass cuttings and kitchen waste - the result is an evil-smelling sludge. Equally, an excess of carbon will significantly slow down the composting process.

Nitrogen typically comes from lush green material and carbon from woody stems. For every barrow load of cut grass, you should mix in the same volume of straw, sawdust or cardboard. Ensure any woody material is broken into small pieces or shredded.

Except for gloss or colour-printed paper, all packaging can be composted. It should be scrumpled up and mixed in equally with the normal vegetable waste to allow plenty of air to get in, rather than placed in lasagne-like layers.


How to do it

Siting your compost bin

1Find a sunny corner of your garden, on soil, where you can site either a plastic compost bin or build a compost bin using wooden pallets or similar. Setting your bin up on soil will allow worms and other micro-organisms from the earth to speed up the composting process.


Adding organic waste

2Start adding organic waste, aiming for an equal mix of green and woody waste (see Monty's compost recipe above). Build up your heap in layers, or mix the ingredients as you go.


3You can speed up the process by turning your heap occasionally with a garden fork, to aerate it, mixing the outside ingredients to the inside. Make sure you cover your bin to keep the rain out.


4When the mixture turns brown and crumbly, and very slightly sweet smelling, the process is complete.


Adam's tip

Avoid sickly plants, such as brassicas, if they have clubroot, and blight-ridden potato and tomato plants.
Autumn is a good time to either dig your compost into the soil, or spread it on the surface, allowing winter frosts to break it down even further. Try sieving compost it first.
Keep your compost warm by covering it with a layer of old carpet or plastic sheeting.



Discuss this project

Talkback: How to make compost
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jazcaz 24/11/2011 at 15:27

i am trying to decide whether its better to cover or not to cover my compost bin....i have two, the covered one dries out very quickly as it gets hot and i have to keep watering it...whereas, the other rots down slower but is cooler as it is not covered...any suggestions please

nanatigtig 24/11/2011 at 15:27

Is 2ft sq to small for a compost bin? I have a very small garden, but have too much kitchen waste for my wormery.

BillinDetroit 24/11/2011 at 15:27

@sheilac: The two do not contradict, but complement each other. Once layered, some of the material is on the inside where it will get quite hot ... 170 F / 75 C for a long time. This will kill off both weed seeds and pathogens.

But the outside edges will barely get warm. Turning the mix evens out this process.

Oh, don't bother adding soil to the mix ... it only makes it heavy while adding no benefit at all. There is no need for any form of inoculation.

fduquesne 24/11/2011 at 15:27

I cover my compost with an old carpet but I'm dismayed by the near immediate appearance of woodlice - and the large quantity that starts to thrive under the warm, dark and wet cover! How to avoid?

BillinDetroit 24/11/2011 at 15:27

@jazcaz: make your piles 1 cubic meter (1x1x1) or slightly larger. At this size they are self-insulating. Adding water is a part of above ground composting and should be done every time the pile is turned or dry material is added. The faster method is the better one, as it is doing a better job of sterilizing the lot.

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