Making compost FAQs

Our compost looks like it has all turned to mush. What can we do?

Most likely, all the fruit and vegetable peelings that have been added to you bin have not been properly balanced out with fibrous materials.

It is important to remember that when adding a lot of fruit and vegetable peelings to compost bins, it should be balanced out by some fibrous materials. Add paper towels, torn up cardboard boxes, cardboard egg boxes, toilet roll centres and scrunched up paper to restore the balance.

I have had my compost bin for 6 months. However, since having the bin I have never turned the matter inside. Is this essential?

Whilst turning compost can accelerate the process of degradation it is by no means essential. The breakdown is a natural process, the likes of which occurs on a forest floor without any manual intervention.

I have been using a compost bin for 15 months and have added a good balance of 'greens' and 'browns'. After checking, everything looked in its original state. Why is this and what can I do?

It may be worth exploring the contents of the bin a little further. As the composting action tends to occur in the middle of the bin, you may find that you have some compost hiding away already.

However, if the contents of the whole bin are largely unchanged, the best course of action would be to give it a good stir. By doing this you will incorporate more air into the mix and it will also help you to correct any imbalance by adding more materials.

If the contents are very dry then add more 'greens' and add some water. If the contents look wet and there is a lot of compacted 'green' material then simply add some more 'browns'. This should help get the process back on track.

How can I get rid of the large cockroaches that are mass-multiplying in my compost?

Cockroaches like warm places, especially to breed, so turning the compost regularly to disturb their nests would discourage them. Being detritivores they are part of the natural waste disposal process.

Make sure the contents of the bin are nice and moist as the cockroaches prefer a dry and warm environment.

I have yellow eggs in my compost bin. When I squash them there is a milky liquid content. Are they harmful and can I use the compost?

If you found them in a cluster they could be worm, snail or slug eggs. These tend to be slimy and are often laid in clumps.

Worm eggs are good, as the more worms the better. It is unlikely that any slug or snail eggs laid will survive whilst in the bin as they will be eaten by predators or decompose as they become compressed within the bin.

How often should I turn my tumble type compost bin?

It is recommended that once you fill your tumbler with material, leave it for a few days to allow the composting process to begin. Thereafter, you should aim to turn it several times each day to ensure that the composting bacteria are afforded as much oxygen as possible and also to prevent any drying out around the edges.

Will compost remain suitable for garden purposes if I have used a poison bait? Will it affect the compost?

Both organic and inorganic chemicals have the potential to remain in your finished compost for some time. There is a chance that some plants could absorb these chemicals through their roots, and transfer this to the edible parts of vegetables, for instance.

Ask the poison manufacturer for the technical information relating to that specific product and the long-term effects of these chemicals in the environment. The poison could harm the beneficial composting creatures inside your compost bin.

For more information on gardening without the use of chemicals, please visit Garden Organic. Garden Organic may have an organic alternative for treating the problem that led to you use poison in the first instance.

Can I compost corn starch containers or should I put them in the recycle bins?

Corn starch packaging is identifiable by the distinctive 'seedling' logo it carries. This indicates that it has been certified as compostable. 

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Why isn't my compost breaking down? I am using a good mix of green and browns.

After approximately twelve months, there should be some signs of dark brown/black compost developing at the very bottom of the bin. When you dig some out of the bottom, you should have a clearer indication of what is going on within the centre of the bin. After this period of time, most of the waste that has found its way to the bottom of the heap should no longer be distinguishable. In order for the compost process to work, it requires four things:

• Food - Aim for a 50/50 mix of 'greens' (young, wet and sappy waste) and 'browns' (old, dry, brittle, more fibrous waste).
• Air - All living organisms in your compost bin need air to breath. Brown material is usually good at providing these organisms with air pockets. Stirring and mixing every few weeks will help introduce air.
• Moisture - Your heap should be as moist as a wrung out sponge. Take a sample from close to the middle. Squeeze the sample in your hand and if the liquid fills the cracks between your fingers, you have enough moisture. If the liquid is pouring out of your hand, then it is too wet and needs more 'browns' adding. However a heap could also be too dry, in which case add some water.
• Warmth - Usually the organisms inside the bin are responsible for this. However, you can help them retain this heat by placing a flattened cardboard box or piece of old carpet on top of the material to insulate it from within.

You might wish to try adding materials which are known to decompose quicker, including comfrey, nettles, and thin layers of grass mowings. These are all high in nitrogen which will get the bugs working.

My compost seems to be growing potatoes from the peelings we have put in. Do we need to empty the bin and start again?

This is a common occurrence and won't have a detrimental effect on your compost, unless the potatoes have blight and then there is a risk of transferring the blight through your compost.

Can I put soil in my compost bin? Will this help the process and quality of the compost?

Placing a reasonable amount of soil into a compost mixture will cause no harm.

Placing soil (about three spadefuls) in the base of a new compost bin will help the process; it will contain the worm eggs and bacteria necessary for the compost process to begin. Adding larger volumes of soil to compost would offer no great benefit.

Two years on, my compost bin is still not producing compost. I am following the rules about greens and browns. What can I do?

If your compost bin is situated in the shade, a few hours sun during the day helps the composting process along. The section on Setting up your bin on this website offers more suggestions.

Should I add meal worms to my compost bin?

Meal worms are the larvae of the flour beetle and are sold as bird food. They will not be very useful in the compost bin as they eat only small amounts of fruit and vegetables.

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My compost bin has started to smell of ammonia. Why is this?

This is a classic symptom of a bin that has too much nitrogen in it.

Normally, we recommend a 50/50 mix of greens and browns - but the best way to deal with an ammonia smell is to increase the amount of 'brown' material. Ideally, try to add two parts 'brown' material to one part 'green' to solve the problem.

How can you sterilise compost to kill off seeds from weeds?

To kill weed seeds the compost must be heated to 60º centigrade, either by heating it in an oven or steaming it.

My compost bin is full of ants. What can I do?

Ants won't do your compost any harm, but are usually an indication that the contents of the bin have become too dry.

If you wish to remove the ants from the bin, disturb them as much as you can by turning the compost and incorporating plenty of 'greens' in the form of grass mowings, vegetable and fruit peelings. You may need to add water to keep the mixture damp.

We put grass cuttings infected with mildew into our compost bin. Do I need to remove the infected layer before adding more waste?

Ideally it would be good to have a range of materials for your compost bin. There is no need to remove the infected cuttings; you will still get compost providing you have a good mix of 'green' to 'brown' material.

As a rough guide, a 50:50 mix of grass cuttings to scrunched up paper, squashed cereal boxes and cardboard egg boxes will ensure that you have a good mix.

Are spiders a welcome addition to the compost bin?

Spiders play an important role within the food chains that exist inside a compost bin. In fact, the broader the range of minibeasts and insects you can attract the better.

Can I compost the cork from a wine bottle; a natural cork, not a plastic one?

Although they will take an incredibly long time to break down, natural corks are certainly valuable additions to the composting process. Apart from providing a food source for some beneficial organisms; being porous, they contain numerous tiny holes which help to both aerate the bin and offer hiding places for other smaller insects.

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I have a toad in my compost bin. Is it absolutely necessary to turn the compost?

People generally turn their compost to incorporate air into the mix to speed up the composting process. However, if you ensure that as you fill your compost bin you mix plenty of drier, air trapping material such as shredded paper, egg boxes and cardboard with your wetter kitchen and garden waste, there is no necessity to then turn your compost as well.

My compost bin sits in the sun and we have black liquid running out of the base. Why does it do this?

It's quite normal for a small amount of liquid to be produced by a compost bin. If you could find a way to collect it you could use it, well diluted, as a liquid feed.

How often should I turn my compost?

The idea of turning the material in a compost bin is to reintroduce air. The aerobic bacteria that do the decomposition need air to breathe, otherwise the process almost stops when they die off. The process is continued by anaerobic bacteria which are much slower.

As the aerobic bacteria work, they produce heat inside the mix. As they do so their air supply gradually depletes until the heat subsides because the bacteria have died off due to lack of oxygen. Turning is required once the temperature has dropped almost back to the ambient temperature. This would probably take around a week.

When the air is replenished by turning, the heat-up-and-cool-down cycle starts again. If you turn a second time, after about two weeks the cycle will repeat. Turn again at the end of the third week. It's unlikely that you'd get any significant heat-up by further turning after that.

I have flies in and around my compost bin. Can you help?

Fruit flies are a normal part of the composting process and are attracted to the sweet sugars being released from overripe fruit and vegetables lying on the surface of the bin.

In the first instance, remove the lid completely and leave the compost bin open for a few hours. This will encourage the flies to disperse and beetles (natural predators) to fly into your compost bin.

Try to ensure that any fruit and vegetable waste is wrapped in newspaper before putting in the bin. If you are using a kitchen caddy, consider a compostable liner made from corn or potato starch, which are 100% compostable. Although you may not be able to eliminate fruit flies altogether, you should notice a marked decrease in their numbers by doing this.

My compost bin is full of mice. How do I get rid of them?

It's likely that the mice are attracted to the warmth and shelter of the bin rather than the materials you are putting in. It is however, good practice to wear gardening gloves when handling your compost.

If you carefully disturb the mice, they should move on and find a new home. Some suggestions to prevent them reinhabiting the bin would be:

• Try to have the bin located relatively close to the house, where it will receive more disturbance than if it was tucked away at the bottom of the garden. Add materials to the compost bin on a regular basis and even aerate the contents now and then.
• Site the bin away from walls and fences so that the area surrounding the bin is exposed.

These measures should do the trick but, as a last resort, wrap the base of the bin with expanded wire mesh (plaster mesh) which can be purchased from a builders' merchant.

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I have fungi growing in my compost bin. I am unsure how it got there and how to get rid of it.

Fungi in your compost bin are quite natural and there are many more microscopic ones. They are all helping to break down your compost.

Can I mix mature compost with the new batch I've just started or is it best to keep it separate?

If the composting process is complete, use your compost and get the nutrients into your soil. If there are plenty of worms in your mature compost you could add some of this to the new compost. This will introduce more worms and mico organisms to get the process started.

Can I compost my tea bags?

Yes - tea bags can be composted in home compost bins. When you use the compost, you may find there is a thin ‘skeleton’ of the bags still visible. These can be sieved out and discarded or dug in with the compost. 

Is there a way to encourage faster breakdown of tea bags?

Some people rip open the bags to ensure that the contents compost down quicker.

However, you will find that the tea leaves will compost down and, if the bags are still visible when you want to use the compost, these can be sieved out and put back into the compost bin to go through the composting cycle again.

Can I continually add to the bin or is there a cut off time for the contents to compost fully?

There is no cut off time. Composting is a continual process; you put in at the top and take away the finished compost at the bottom. If the amount in your bin is reducing, it's working!

What pH would a typical compost heap have?

There isn't a definitive answer as it very much depends on what the compost was made from.

It is frequently said to be on the alkaline side of neutral. If you are concerned about using it around acid-loving plants then consider buying an inexpensive pH soil testing kit and testing your compost before use.

How much does the volume reduce during the composting process?

Generally, irrespective of compost bin type and conditions, the volume would reduce by 1/3.

A Royal Horticultural Society experiment using black plastic bins, wooden bins and open heaps revealed that all bin types irrespective of turning, yielded around 1/3 less compost than the starting volume, of which 80% was determined as being made up of fine (less than 10mm) particles.

I have leather jackets in my compost bin; how do I get rid of them?

As you may know, leather jackets are the larvae of the crane-fly (daddy long legs) and these grubs generally feed on the roots of grasses. This may have been how they have entered your bin.

We would not recommend using chemicals to eradicate the larvae found in your compost bin as they are also likely to kill off any beneficial insects. You could try to remove the leather jackets by sieving the compost first, and then picking out any that are left.

I have found a slow-worm in my compost heap. What shall I do?

The slow-worm is one of the most commonly encountered British reptiles and is often found in gardens throughout the British Isles and can be found in almost any open or semi-open habitat. Slow-worms are keen on compost heaps where they find warmth and plenty of food. They feed on slow moving prey, particularly small slugs.

Slow-worms are protected by law so please be careful when turning your compost to ensure that you do not hurt or frighten them. Slow worms may lay eggs in your compost so care should also be taken not to damage the eggs.

In most cases the slow-worm will disappear on their own but, like most reptiles, they need warmer weather to move about freely and will hibernate when the temperature drops.

For further information, please visit The Amphibian and Reptile Conservation Trust website.

Bumble bees seem to be active around my compost bin. Should I be concerned?

Bumble bees are sometimes attracted to compost bins. Usually they prefer old, reasonably dry compost heaps or bins - one that has lots of fresh material would probably be too damp and messy for them.

Bumble bees are very docile and will only sting if hard pressed; a nest near a house is not a problem.

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Would my compost heap make a comfortable home for a hibernating hedgehog?

It was once thought that hedgehogs would be hibernating by the end of October, when in fact, many are still out in December, and some even until January when the hard frosts descend. They hibernate as a last resort when their natural food supply has all but disappeared. Your warm compost heap makes an ideal nest for those looking for a quiet place to hibernate.

Please refrain from turning your entire compost heap over at this time of year. This could injure or kill your visitors who help reduce the number of pests in your garden in a pesticide-free way. Hopefully you will have struck a good balance of 'greens' and 'browns' in your bin already which will help keep the pile aerated as it settles, reducing the need to turn the pile.

Due to milder winters, a growing number of baby hedgehogs are being born later in the year and have no hope of making the necessary weight before the onset of winter, so will need your assistance. Sick, underweight or injured hedgehogs should not be allowed to hibernate, as they will not survive the winter. Should you find a hedgehog that needs help, please contact your local wildlife centre or St Tiggywinkles Hospital for advice.

What can be composted over Christmas?

It's surprising how many Christmas items can be composted. We have come up with some suggestions which we hope you will find useful.

• A third of your kitchen waste can be composted. Fill your kitchen caddy with those Christmas fruit and vegetable peelings, teabags, coffee grounds, paper towels and eggshells. Even Rudolf's uneaten carrot can go in!
• Once the presents have been opened, wrapping paper and gift tags can be scrunched up and added to the mix. Be careful not to include wrapping paper made from plastic film or heavily glittered tags.
• Cardboard packaging from Christmas toys and gifts will add fibre and structure to your bin, as will the additional paper and cardboard packaging from your kitchen store cupboard.
• Paper napkins, Christmas cracker inners and party hats from your Christmas table are also good compost ingredients.
• Wood ash from open fires can be put into your compost bin; after Santa has been, of course!
• The remnants of your New Year's Eve party can also be composted - nut shells, cocktail sticks, paper plates and some party food packaging. Natural corks will take longer to break down but can also be added to your compost bin.
• With additional visitors over the Christmas period, there is bound to be vacuuming to do. The contents of your vacuum cleaner can be emptied into the compost bin.
• Holly, mistletoe, paper chains and decorations can also be composted after Twelfth Night.

I have resolved to start composting at home in the new year. Can I start in January?

January is often seen as the time of year when we all try to change our ways. Composting at home is a great way to reduce the amount of waste you throw away, and not only is it good for the environment, it can also be a great way to put cardboard packaging from Christmas presents and paper hats and napkins from New Year celebrations to good use - as well as all your vegetable peelings from those extra guests!

By starting now, you may have some nutritious compost ready to use in the growing season on flower beds, vegetable plots and in patio planters, hanging baskets and window boxes. Even during the winter months, there is still material you can add to your compost bin, such as egg shells from Shrove Tuesday pancakes or faded Valentines Day flowers.

To get started, follow the tips detailed below.

• You will need to add the right ingredients - a 50/50 mix of 'greens' and 'browns' makes great compost.
• Avoid adding cooked vegetables, meat and fish, dairy products and diseased plants to your compost bin.
• Make sure you give your compost an occasional turn; this will give it some air which is essential to the composting process.
• For the winter weather, invest in a kitchen caddy to reduce your trips outside to the compost bin.

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