If you are having any problems with composting, below are suggestions to help you resolve some of the most common composting issues.

Not getting any compost?

The most common reason for not getting any compost is not having the right moisture level in the bin. You should aim for a 50:50 mix of green materials like grass that provide moisture and brown dry materials like leaves which form air pockets. See the full list of what can go into compost bins.

If you have the right mix you could check your bin location isn’t too sunny or shady. Ideally the bin should get periods of both during the day, you can move the bin to a different position to help. Alternatively if it is in too much sun add moisture by letting rain water in, or preserve heat by insulating the bin with material (like old carpet) in colder places or the winter.

It’s taking too long to compost

Rotating composterIt usually takes 9-12 months for compost to form.  If your compost bin or heap is taking longer, first check you are adding the right balance of materials. You should have a 50:50 mix of green materials like grass that provide moisture and brown dry materials like leaves which form air pockets.

The heap should be as moist as a wrung out sponge. If you have the right mix of greens and browns, try adding water to a dry bin, or for a wet bin you may need to help increase the heat, so the material rots down.  Cover the compost surface to keep the warmth in or try moving the bin into a more sunny position.

Turning the material in a compost bin speeds up the decomposition process by reintroducing air pockets. Some use a rotating compost bin to make mixing easier while others use a mixing stick or empty the whole compost bin, kick the content around a bit wearing boots and then restack.

Too wet or too dry

If the mix of greens and browns are not equally balanced the compost can become too wet or too dry.

  • If it looks too dry and/or ants appear add some greens or water - try leaving the lid off when it's raining.
  • If it looks or feels very wet or smelly and slimy, add in more browns. Cardboard packaging from eggs, cereal boxes are a good counterbalance to moisture rich green material like kitchen waste and cut grass. The structure of the cardboard will aerate a heavy heap, however, it can sometimes take a while to rot down – tear up the cardboard before adding to the mix, as this will help keep air circulating in the bin.

A lot of grass cuttings put onto the compost bin can introduce too much moisture in one go. Make sure to add browns (dry materials) to balance the mix.

Turning the material in a compost bin/heap also helps reduce wetness by introducing air pockets, which speeds up the decomposition process and reduces smells.

You can also try moving the position of your bin to a sunnier or shadier location, to help dry out a bin or keep it moist.

Avoiding rats in your compost bin

It is very rare for rats to be attracted to compost bins. However, if they are it is likely to be due to incorrect waste items being placed in the compost bin such as cooked food, dairy products, meat, fish or bones. For more information see the full list of what can go into compost bins.

Rats are shy creatures that don't like disturbance or noise - so continue using your bin to keep them away. You could also put fine mesh wire under the bin to prevent them digging into it from below.

Insects in your compost bin

Insects are essential in breaking down the wooded and carbon rich material within the compost bin. In fact, the broader the range of mini-beasts and insects you can attract the better.

The presence of lots of ants can indicate a dry bin, so check you're adding enough greens or add some water.

Small flies in the bin

Fruit flies in your bin do not carry disease and do not harm your compost. However, if you find them unpleasant you can reduce their numbers by ensuring that the waste intended for your bin is always covered in the kitchen or wherever it is stored. Don't use fly spray.

What plants are unsuitable for composting?

There are some plants that are not suitable for composting:

Can diseased plants be composted?

Diseased plants should not be composted at home as small compost heaps do not get hot enough to kill infections. You can take them to a recycling centre from where garden waste is sent to large scale composting sites where temperatures within the heaps get hot enough to kill infections.

Too many leaves – make leaf mulch

If you have too many leaves for your compost bin make leaf mulch:

  • Collect them up, and if the leaves are dry, moisten them with a little water.
  • Bag up the leaves in a large bin bag and punch holes in it to allow air to circulate.
  • Place in a corner of the garden.
  • Leave the bag for between one and two years. The longer you leave it, the finer the leaf mulch will be.