Making Garden Compost

Making garden compost is one of the most satisfying tasks a gardener can tackle. There’s nothing like seeing a mess of lawn clippings, teabags, vegetable peelings and discarded bedding plants being transformed into a rich brown sweet-smelling mixture that can be used all around the garden to put heart back into the soil.

What makes homemade garden compost so special?

It feeds the soil
It improves soil texture, making the soil both moisture-retentive and free-draining
It encourages beneficial micro-organisms
Recycling kitchen and garden waste is better for the environment
It’s cheap, easy and satisfying to produce

Many gardeners are disappointed when their first attempts at making compost end in a slimy, foul-smelling mess. Other gardeners find that their compost heap doesn’t seem to do anything at all, and that even after several months nothing has rotted down. Most composting disasters happen either because the compost heap is too wet, too dry or is poorly mixed. Follow our step by step guide to making perfect compost.

Heap or Bin

What you choose to house your compost will depend largely on the space available. Plastic bins and tumblers, wooden containers, slatted boards – all can be used successfully. Go for the largest container you can fit in your garden – better still have two or even three. That way you’ll always have some compost ready and some in the making. A bin that is open at the bottom is best placed on soil rather than concrete.

Compost Ingredients

To rot down quickly your heap should have a balance of green nitrogen-rich waste and brown carbon-rich waste.

Kitchen waste including vegetable peelings, tea-leaves, coffee grounds, banana skins, citrus peel (but not too much)
Grass clippings – try and mix them in
Annual weeds
Prunings from roses, trees and shrubs – chop these small
Discarded bedding plants
Hedge trimmings
Sawdust from small animal cages, feathers and fur
Fallen leaves – keep separate if you have a lot
Cardboard and newspaper – useful if your heap gets soggy

Definitely Not

Think of your compost heap like a stir-fry. You want a balanced mixture of good quality ingredients. Do not add:

Diseased plant material
Perennial weeds e.g. dandelions, ground elder, bindweed
Discarded cat litter
Dog faeces
Cooked food – may attract foxes and rats
Weeds that have gone to seed

To Shred or Not to Shred

Woody stems will rot down more quickly if chopped small. A shredder is invaluable in a large garden where there are lots of hedges and shrubs to be pruned. For small quantities use secateurs.

Building up the Heap

A compost heap can be cool or hot. A cool heap has small amounts of material added over several months. A hot heap is built all in one go using a large amount of material. Either method will produce good quality compost but the cool heap will take longer. The composting process happens much more rapidly when the weather is warm and a cool heap started in the spring should produce some usable material by the autumn.
Whichever method you are using, try to ensure you mix together a selection of both soft and hard waste. This is particularly important with a cool heap where you will be probably adding a layer of lawn clippings one week and maybe some hedge prunings the next week. Mixing the two together with a garden fork will help both of them to rot down more quickly and evenly.

Using a Compost Activator

Compost activators such as J. Arthur Bower’s Garotta and Growing Success Activ8 are useful to kick-start the composting process. They are high in nitrogen, which stimulates bacterial activity. In a cool heap add 2-3 tablespoonfuls or a handful of granules onto each 3 inch layer of new material. When sprinkling the granules over the heap take the opportunity of mixing the material with a garden fork if possible.

Alternatively you can use New Horizon Organic Compost Maker which comes in a liquid format. Just add a capful to water in a 5-8 litre (1 - 1¹/₂gallon) watering can and sprinkle onto each layer of new material – the precise amount of water is not crucial as long as you add enough to wet the new composting material.

Always add the compost activator on top of the new material in order not to disturb or touch any worms which are active in the heap. Lawn clippings are already high in nitrogen so you may not need to add a special activator if you have a lot of lawn clippings in your heap. Make sure you mix the lawn clippings in thoroughly.

Using Your Compost

After six months (less in a tumbler) you should find that a miracle has taken place. That bulky heap of garden and kitchen waste will have shrunk in volume to product a brown, moist and crumbly material with a pleasant smell. This compost can be used in many ways:

As a mulch around existing plants
As a soil conditioner dug into new beds
As a planting mixture – fork into the planting hole and mix it with the soil. A handful of bonemeal is beneficial to help the plant's roots get off to a good start.

If space is limited it’s a good idea to clear your bin out each autumn. Set aside the compost that is ready to use and put back all the unrotted material. If you have two bins transfer the newest material from the top of the heap to the bottom of the other heap.

Compost Problems

Too Many Lawn Clippings

Many gardeners find in summer that virtually all their garden waste consists of lawn clippings, which can quickly turn into a slimy smelly mess. This is where junk mail or old newspapers can come in handy. Layer the grass clippings with strips of unwanted paper (but not glossy paper). It’s a good idea to turn the heap each time you add more clippings to introduce some air into it. If you have coarse twiggy material do mix that in as well.

Lots of Leaves

You might think leaves were the perfect compost ingredient. However, they contain high amounts of woody tissue called lignin and will slow down the composting process. It’s much better to compost fallen leaves separately. For large quantities make a container using chicken wire wound round some posts. Tread the leaves down from time to time. For small quantities put leaves in black binbags, water well with New Horizon Organic Compost Maker and leave for a week (three days if the leaves were already wet) then pierce holes all over the bag with a garden fork and store in a shady place. Use leafmould as garden compost, especially in woodland borders. You can also use sieved leafmould to make your own potting compost.

Flies, Rats and Other Unwanted Visitors

Rats and flies are always on the look-out for food. Keep them at bay by never putting cooked food or bones onto your compost heap. Don’t worry if you get tiny flies – these are most certainly a type of fruit fly that feed on organic matter. They will not do any harm. They can become a bit of a nuisance around an open heap – the best thing to do is cover it with a piece of old carpet or compost duvet.

Won’t Rot Down

Some gardeners find that their compost doesn’t seem to rot down and that even after several months individual components are still visible. The most likely reason is that the heap is too dry or that there is too much twiggy material and not enough soft green waste. The micro-organisms needed to maintain the rotting down process will only be present if the mixture is damp. Water the heap with a solution of New Horizon Organic Compost Maker, making sure all the material is wetted. If possible, add some grass clippings or kitchen waste. It’s also a good idea to cover the heap with a piece of old carpet as this will help to retain heat and moisture