Composting FAQ & Troubleshooting
Why Compost and other general questions
Why should I compost?
Because it’s easy, can save you money and stops literally tons and tons of material clogging up landfill unnecessarily. Plant matter and kitchen scraps rot down to compost pretty much wherever they end up – but in landfill, they can’t be reclaimed and used. By composting, you’re keeping it out of landfill in the first place and you’ll get to use the lovely, rich compost on your own garden, instead of having to buy in commercial compost or fertilisers to keep your soil healthy.
But I don't have a garden! Can I still compost? Is there any point?
While it’s easiest and most beneficial to compost if you’ve got a garden, you should still compost to stop that waste going to landfill. You’ll probably find someone who would love to take your homegrown compost off your hands when you’re done – or you can use it yourself for houseplants and window boxes.
If you have a small amount of outside space, you will probably be better having a dedicated composting bin (possibly even a sealed one) to keep things neat and also speed up the composting process.
If you have no outside space whatsoever, talk to your landlord, housing association or local council to see if they’ll install a communal composting bin near your usual bin collection spot, or nearby.
Can I Compost....
If you’d like to know whether or not you can compost something in particular, search our database to find out:
If we haven’t covered your item, get in touch and we’ll add it to our list as soon as we can.
Can I compost kitchen scraps and garden waste in the same bin/heap?
Yes! And your household waste too. In fact that’s a great way to keep it balanced!
Do compost heaps smell?
Avoid adding potentially stinky things like fish/meat scraps, dairy or animal faeces – our “don’t compost that!” list includes lots of things that might cause an odour problem.
Will my compost heap/bin attract rats or foxes to my garden?
If you stick to our what to compost/what not to compost advice, then no, it won’t. A lot of kitchen scraps are on the “don’t do it!” list almost entirely because they might attract undesirable scavengers.
If you’re really worried about that type of thing, go for a purpose-bought or completely enclosed DIY compost bin rather than an open heap – that’ll cut down on attractive-to-vermin smells in the first place and if they do find it, make it hard for them to get in and mess it up.
When can I use my compost? What can I do with it?
Most compost heaps need 6-12 months to breakdown properly – some work faster, others slower, depending on what type of stuff you’ve put in it.
If you’ve got a purpose-bought compost bin, there will probably be an “access hatch” near the bottom to check on its progress. If you have a heap or homemade bin, you’ll be able to see how it’s going when you turn it over (see below).
It is ready for using when most of the material has rotted down into lovely rich soil. If you can still see lots of individual leaves or bits of vegetables, leave it a bit longer but don’t worry if you can still see harder items like twigs or egg shells – they take ages to rot down.
As for using it, it’ll probably be bulkier than the compost bought at the garden centre so not really useful for seedlings in little tiny plant pots. It is though perfect for digging into flower beds or vegetable patches to enrich the soil before you plant on those seedlings.
Setting up your heap or bin
Do I need to buy a proper composting bin?
No. We recommend it as the easiest option for beginners because they’re not usually that expensive and get you up and running straight away. As they’re largely enclosed, usually with a lid, they also do a good job of keeping vermin out and keeping heat & moisture in. They also tend to have an “access hatch” at the bottom so you can keep an eye on its progress and get access to the finished compost without digging through new matter.
But they’re by no means essential – people have been composting for thousands of years without formed plastic bins — and the earth has been composting for millions of years before that without any type of bin at all!
What is better a bin or a heap?
Both have their own advantages and disadvantages but in general, if you’ve only got a little space, you’re probably best off with a neat bin. Conversely, if you’ve got more space or a lot of stuff to compost, a semi-enclosed heap (or ideally, a couple of them) will be better for you.
Where should I put my compost heap/bin?
It depends on the size and layout of your garden really but ideally, you want to put it somewhere that is
- Convenient and accessible, but not in the way
- On bare soil or grass to help with drainage
- In a partially sunny spot – warmth will help it rot down quicker.
It’s most important that it’s convenient and accessible for you – because if it isn’t, you won’t use it. The other two are desirable but not essential.
Should I put my heap outside or inside my greenhouse/shed/garage?
Most people have an outside compost heap or bin.
While the warmth of a greenhouse or a heated garage would help speed up the composting process, compost could easily become too dry indoors, thus slowing down the rotting process or at least requiring regular watering. Conversely, there might be drainage issues: any excess moisture has to go somewhere and in my experience, dirty liquid always finds the least desirable exit path! Finally, while most healthy compost heaps aren’t too stinky, the general earthy aroma of compost will be a lot stronger inside: that alone usually puts people off keeping them indoors.
Some people with large greenhouses or polytunnels do keep their compost bins inside: for convenience while working in there and because they’re usually already committed to watering/have a watering system in place. People with small greenhouses though generally don’t want to waste their precious warm space on compost – a caddy to carry it to their compost heap or a bin outside their greenhouse door are generally convenient enough.
Does my bin/heap need to be on a solid base?
No. In fact, having a(n open bottom) compost bin on concrete or a patio can cause problems for drainage. Make a layer of criss-cross twigs and sticks at the bottom to get around that: the water will drain through those rather than sitting in the bottom layer of compost.)
Do NOT place the heap or bin on wooden decking: while most decking is protected against the elements for a number of years, a constant load of warm, wet compost on top of it will cause it to rot sooner.
Ideally, place your bin on bare ground (or grass) – excess moisture can wick away and worms and whatnot from the earth can make their way into the compost.
How big should my compost heap be?
It depends how much you’re going to put in it. A couple or small family just composting kitchen scraps & household waste will be pushed to fill a standard size (220litre-ish) compost bin – it’ll breakdown almost as quick as they’re adding to it. A family with a large garden will quickly fill that – an end-of-gardening-season pruning session would probably fill it on its own.
If you will be composting a lot of stuff and have the space, it might be worth building two (or more) heaps so you can have one that is active and one that is rotting down. A lot of people scavenge wooden pallets to make compost heaps (ask around, you can usually get them for free) and use those as a guide for setting size to minimise sawing – they’re about a metre square.
What's the difference between a compost heap and a wormery? Which is better?
A compost heap usually has a few resident worms to help the composting process but wormeries are, as the name suggests, considerably more worm-heavy: they’re the primary composting agent.
Wormeries generally produce a finer compost than a standard heap and also generate a concentrated liquid fertiliser – but they require more management. They’re ideal for kitchen scraps but not suitable for large amounts of household waste items or garden waste.
Compared to wormeries, compost heaps are a free for all: easier to manage on a day to day level and capable of composting a wider range of things, but producing coarser compost.
Do I need to add worms to a compost heap?
If you have your compost heap or bin on bare soil or grass, some may find their way in there of their own accord but you don’t need to add them, no. They will help the compost heap work faster but aren’t necessary.
If you feel like investing, special composting worms are better than regular earthworms: the former love to live in decomposing materials while the latter prefer actual soil. You can buy composting worms online.
Keeping your compost heap healthy
Do compost heaps require ongoing maintenance?
At the most basic level, no. Just keep adding stuff to them and after a while, you’ll have compost.
However, if you can turn it regularly (stick a garden fork in it and flip it over), it’ll help speed things up. Similarly, it’s useful to keep an eye on it to make sure it’s not too wet or too dry, and a reasonable balance between greens & browns (see below) – those things will help it rot down faster and result in a richer soil at the end, but aren’t 100% necessary.
How often do I need to turn my compost?
It depends how often you add new stuff to it, how well it’s composting and how soon you want the compost.
Turning the pile introduces new material and air into the centre of the pile – where it’s hottest and the decomposing microbes work the fastest.
If you’ve got a hot compost heap, the microbes will use up their air supply faster so you probably want to turn it once a week or so.
If your compost pile is cooler/composting slower, turn it over about once a month to introduce new material into the centre – and to check on the progress of it.
I read that I should turn over my compost but I physically can't do that. Is it essential?
Turning over your heap with a garden fork helps keep it aerated – the microbes that do the decomposition need air. It’s often difficult to turn compost in tall bins though, even for the most atheletic and agile, so don’t feel too bad if you can’t do it. Instead, help keep your compost aerated in other ways – add bulky items such as cardboard toilet roll tubes, egg cartons or cardboard boxes regularly to help bulk it out and keep pockets of air in the middle as you fill it up.
What are greens and browns?
Composters often talk about “greens” and “browns” – basically, greens are freshly grown things (veg peelings, grass clippings) and browns are older items (cardboard, wood shavings). Green things are said to be nitrogen-rich while brown things are carbon-rich – and the best compost heaps contain a balance of the two. Balanced heaps rot down quicker and produce richer compost than ones that are all green or all brown.
Help! I've put something in that I shouldn't! What can I do?
It depends what it is but most of the time, it’s ok, don’t panic.
Everything made from organic matter will rot down eventually – your heap might just take a bit longer than it would to be completely composted or you might find once everything else has rotted down, you can pluck out the offending item.
If you’ve added a plant that is diseased or something on the “don’t compost” list for some other reason, be careful about how you use that compost when it’s ready – say, if you’ve composted blight-infected tomato plants, don’t use that compost for your tomatoes (or anything similar) next year. Similarly, if you’ve added something to the heap which will leak potentially harmful chemicals, make sure you keep that away from your veg bed.
If you’ve added some kitchen scraps on the “no” list such as dairy or meat products, you might see an increase in vermin/feline interest in your heap but they should rot down quickly that it won’t be a problem for long.
If you’ve accidentally added something that won’t compost – stones or plastic for example, you might be able to pluck them out of the compost when it has rotted down.
Depending on the severity of the problem, if you’ve got enough space for it, you might want start a second compost pile – you can then have a “uncontaminated” one which you can use more widely.
You say don't compost X but I've always composted that without problems. Why do you say no?
The Compost This guide is very cautious about what you can and can’t compost because we don’t want newcomers to have bad experiences of composting – things not composting down, things growing, the heap smelling or it being a draw for the local animals etc.
Those with sealed bins or composting systems, or wormeries, will be able to compost a wider range of kitchen scraps – and we make note of this where appropriate.
Experienced composters know, from their own experience, what’ll work in their compost heap and what won’t – and we do try to take that into consideration, but we want to be, for want of a better term, an “idiot’s guide”: if you follow our yes and nos, you’ll considerably more likely to have first composting success. We don’t like to call Compost This an “idiot’s guide” though because if you’re interested in composting, you’re not an idiot, you’re ace! :)
Troubleshooting problems with your heap
My compost heap is too wet. What can I do?
First off, add more browns to soak up the excess moisture: crunched up newspaper, wood shavings or cardboard are ideal – the cardboard can be corrugated stuff or things like toilet roll tubes and egg boxes.
Next, try to identify the source of the excess moisture: is it that you’re adding a lot of wet things? or because it’s getting rained on regularly? If you’re adding a lot of wet things – dregs from the tea pot or urine for example, keep adding those extra browns to soak it up as you go. If it’s more of an environmental factor, cover your heap/bin – either with a lid (if you have one) or with a (weighted-down) tarpaulin.
My compost heap is too dry. What can I do?
Add more moisture! ;)
This could be in the form of compostables (gone off fruit juice, the dregs from your coffee pot), waste water (from washing/cooking your veggies, from rinsing off the muddy dog) or just dumping a bucket of water onto it every now and then. Alternately, if you’ve got a lid or covering, try removing it periodically to let the rain in.
If the extra water is just running off, make a well in the middle of the heap, like you do when adding liquid ingredients to flour. It’s also a good idea to turn the heap to ensure the new moisture is evenly distributed.
In the long run, you might want to adjust your green/brown balance (greens such as fresh garden clippings or veg scraps are usually moister) or if your compost heap is being baked in the midday sun, add some sort of shading to deflect the strongest rays.
My compost heap stinks! What can I do?
A stinky heap is usually a sign something is wrong.
Have you added something you shouldn’t (like meat scraps or animal waste)? Or has an animal being adding its own waste without your permission? A tarpaulin covering will reduce the latter happening on an open heap. If you (or some other creature) has added something you shouldn’t and can’t remove it easily, try turning it into the middle: it should compost a bit quicker there. (Though depending on what it was, do be careful about how you use the resulting compost.)
Is the heap too wet or looking a bit sludgy? That can make it smell like a stagnant pond. Add more browns to soak up the moisture.
Why is my compost is taking ages to rot down?
Chances are, it’ll be too cold, too dry or not aerated enough.
The microbes doing all the composting work best in a warm, moisture environment. The composting process generates heat but if the weather is cold or the compost too spread out, that heat will dissipate too quickly. Gather it into a smaller area if you can and covering it with a lid or tarpaulin will help it retain some heat. If it’s not wet enough, see above for some ideas on how to add more moisture to your compost.
Composting bacteria and other micro-organisms are aerobic: they need to take in oxygen and output carbon dioxide. If a compost heap becomes too densely compacted, the air flow is reduced: the available oxygen depletes and their environment becomes carbon dioxide heavy. Decomposition seriously slows down in those conditions: think how much slower you’d work if your air supply was severely impeded! Avoid that happening by making sure there is a good amount of bulky browns in your heap and turning over (or stirring) the compost regularly.
A good green/brown balance will prevent a heap from getting too dry and help preserve airflow.
Why are there thousands of tiny flies in my compost heap?
They’re probably fruit flies, attracted to the rotting fruit and vegetable matter on your compost heap. They’re a nuisance rather than a full on pest but if you want to try to reduce their numbers, stir your new kitchen scraps into the middle of the heap.
Why are there plants growing in of my compost bin?
Because the seeds (or tuber) of something you have composted has grown rather than rotted down.
Certain things – some weeds, potatoes and tomatoes for example – are particularly prone to growing in the compost heap. It’s no surprise really – to germinate, seeds & tubers usually like a nice rich soil, that’s warm and moist – or exactly the same of the conditions in a compost heap!
Some people consider these as “freebie” plants: they let the potatoes grow in place or transplant the tomatoes to grow on elsewhere. Others prefer to just pull them up – if you don’t know the origin of the parent plant, you don’t know its variety or if it was diseased etc. Don’t leave things to grow in there without dealing with them – else the problem might be even worse next year!
To decrease the chances of it happening again, cut up things like potatoes into small pieces, avoid adding seed heads from weeds and scoop out seeds from prolific fruits like tomatoes. Good compost heap management also helps: hot or particularly efficient compost heaps begin decomposing the seeds before they have time to sprout.
There are lots of little white sacks throughout my compost. What are they?
While some brands use entirely natural fibres in the tea bags, many of the main brands (especially those that have “heat sealed” edges) use synthetic fibres – and they don’t rot down. (Or they break up a bit but leave tiny synthetic fibres mixed into your compost.)
If you’re concerned about introducing synthetic fibres (typically polypropylene) into your compost heap, you can either avoid composting your teabags, or empty out the tea into the compost & bin the bag separately.
If you’re happy with the little fibres though, you can compost the teabags as normal, and just pluck out the little bags that remain after everything else has composted down.