What do we mean by “yacky”? Well, anything on the “don’t compost this” list really – if you’ve used your toilet tissue to wipe your nose or your bum, it should go down the toilet rather than in your compost heap. It might attract unwanted pests to the heap or could be harbouring nasty bacteria or pathogens which might not get broken down composting process.

You should bin it if you’ve used it to clean up most pet waste or oil spills, or used it in connection with chemical cleaners/agents too – that’s not stuff you want in your lovely compost.

Toilet paper with a bit of wee on them are fine though – you can compost that (as long as the producer is healthy). Ditto tissues used to wipe up a little bit of blood.

The inner cardboard tube can be composted too.

Normal newspaper adds lots of great carbon to a compost heap – soaking up excess moisture and if they’re scrunched up, helping air circulate in the heap and prevent it from becoming too compacted.

Newspaper will rot down quicker if it’s damp but for best results, try to alternate layers with other matter – ideally fresh green stuff like garden clippings or veg peelings.

Avoid heavy stacks of newspaper as they’ll take longer to break down and shut off air to the rest of the heap – if you’ve got a lot of newspaper to get rid of, it would be better to recycle it through your paper recycling bin instead.

Oh, while newspapers are great, don’t compost glossy colour supplements or leaflets that came in the paper though. Recycle those too instead.

Also see: Recycle This for How can I reuse or recycle old newspapers?

What types of water NOT to add

Basically, don’t compost any water that has been mixed with anything on the “don’t compost” list.

Soaps and other chemicals are bad news for a compost heap. They will kill the delicate microbes that are busy doing the composting work — most of the cleaning chemicals and soaps we use around the home are purposely design to kill bacteria and the like but in a compost heap, those guys are our friends!

Whatever chemicals or other pollutants are in the water will also contaminate the resulting compost – possibly not such a big problem with a bit of soapy water from washing your hands but more of a problem for things like petrol, paint or fecal matter — not things you want getting into your veg bed!

Stagnant water, even if it was clean to start with, should not be composted because of the risk of Legionnaire’s Disease and because it also can inhibit our friends, the composting microbes.

Flood water also shouldn’t be composted – unless you know for sure that it hasn’t come into contact with any nasty substances. (Flood water can pick up all sorts of petrol-y substances from roads and in a bad flood, sewerage can flow into river courses etc.)

What CAN be added

Basically, any water that is either clean or only mixed with things that can be composted.

Water from cooking – such as from boiling pasta or vegetables – can be added but only if it is free from oils (cooking, butter or animal fats) as they can attract vermin to the pile. (You can also use that water in stocks, soups and baking – see our water page on Recycle This for more information and ideas.)

How to add water to a compost heap

As mentioned at the start, moisture is an essential part of the composting process. Some people choose to leave their bins or heaps open so they can soak up rainwater as they go, but if you’ve got a lid or a covering, you will probably needed to add some liquid at some time or another (especially if you’re adding a lot of browns)

When adding water to a compost bin or heap, add it to the centre of the pile and stir it through if you can to get the maximum benefit – that’ll stop it simply dampening the top layer and make sure the often-warmer middle won’t dry out.

Do try not to over-wet the heap though. Overall, the compost should be moist not wet. This is particularly important if you’re using a sealed compost system – most purpose-bought compost bins have drainage holes (or a completely open bottom) to allow excess water to drain out.

Corrugated cardboard typically adds bulk to your compost, helps preserve the necessary air flow and soaks up excess moisture too. (Other raw fibreboard items like egg boxes or toilet roll tubes work in the same way.)

In composting terms, it’s a brown item: make sure you add it alongside fresh greens – like kitchen scraps or garden cuttings – to your compost heap balanced and as it sucks up moisture, add extra liquid if your compost pile has a tendency to be on the dry side. (Cardboard rots down much quicker if it’s wet and torn into small pieces – tearing it up is easier if it’s damp too.)

A couple of warnings though: do peel off any plastic packaging tape/document pockets as they won’t compost and be careful when composting shiny cardboards – that shininess is often the result of a plastic coating or using other synthetic materials.

You can compost:

These ashes are fine in small amounts – but be careful as it can very quickly made the heap to alkaline. (This might be desirable for balancing out acidic compost heaps or acid soils but in most circumstances, it’s better to keep it neutral overall.) Mix it into the contents of the heap to avoid the small particles being blown around on the wind.

Make sure ashes are thoroughly cooled before adding them to your compost heap, otherwise dry materials in the compost may fire risk.

These ashes can also be used “neat” on the garden as a slug deterrent and soil fertiliser, or reused in other ways too.

But don’t compost:

All these types of ash contain materials that are harmful to plants or animals, or in some cases, the wider ecosystem.

If in doubt and especially if you’re using your compost for growing edibles, leave it out.

Basically, as you might have guessed, natural fibres will compost down but synthetic ones will not.

Clothes made from synthetic fibres – such as acrylic yarn, polyester/nylon fabrics or microfibre fleeces -shouldn’t be added to the compost heap as they won’t break down – they’ll just clog up your compost heap.

Items made from entirely from pure wool, cotton, silk, linen, hemp and ramie (or a blend of any of those) will compost down – but they will all take a while (their durability is one of the reasons why we make them from them rather than, say, paper). Tear them up to help them rot down quicker.

Keep in mind that many items that claim to be made from 100% natural fibres, like cotton t-shirts or jeans, may still use polyester “cotton” for their sewing thread (since it’s cheaper & strong than actual cotton thread). That won’t break down so you might end up with some strings left in your compost heap – once everything else has rotted down around it. (They should be relatively easy to pluck out though.)

Blends of natural and synthetic fibres are more of a judgment call, depending on the mix. If it’s more synthetic than natural, then almost definitely leave it out but if it’s only includes a little synthetic material, then you might consider adding it. The synthetic part might break up but will still not break down – you might be left with either lots of little tiny pieces of it throughout the compost or some longer strings, depending on how the synthetic material was incorporated. If you want to keep your compost heap free from synthetics then obviously leave them out, but if you’re not so fussy, you can add them and pluck out longer strings afterwards.

Don’t compost any clothes that are stained with things from the “do not compost” list – like paint or engine oil – as you don’t want that in your compost heap.

If you’re using your compost for veg growing, you also might want want to leave out natural fibres that have been extensively dry cleaned or include heavy prints to avoid residue chemical contamination. And definitely avoid composting items like t-shirts which have slogans or designs that seem to sit on the fabric rather than ones that are part of the weave or have soaked in – that’s usually a sign that it’s been printed with PVC inks and plastics like PVC will not break down.

Clothes made from natural fibres are a “brown” in composting terms – make sure you add them alongside fresher, wetter items (like veg peelings or garden cuttings) to ensure they break down in a timely manner and your heap stays balanced. And don’t overwhelm your compost heap with old clothes – no more than 25%.

Before you think about composting any old clothes though, do try to reuse (or allow others to reuse) the items first. Donate still wearable items to charity shops/charity collection bins or sell them on eBay. Cut up old cotton items to use as cleaning rags. If you can sew or are the crafty type, you can upcycle the item as another piece of clothing or use the fabric as a material for other crafts. Finally, textile reclamation specialists (aka “rag men”) take old clothes and reclaim the fabrics for industrial use (such as for insulation). All of those are better reuses for fabric than simply composting them.

In the case of things like wine corks, make sure they are actually cork and not plastic made to look like cork. Synthetic corks are increasingly common in newer wines for a number of reasons – but they won’t rot down in a compost heap. If you’re unsure, cut it open to check – synthetic corks are usually a uniform foaminess inside while real cork is a bit more random and looks a bit woodier.

If it is real cork, make sure you remove any packaging that might be attached to it – for example, plastic screw lids or foil covers.

Cork noticeboards and cork tiles can also be composted but if they’ve been painted or stuck down with glue, leave them out of your heap – not only will they hinder the decomposition process, you’ll potentially be adding a lot of unwanted chemicals to your lovely compost.

As with most composting, break or chop them up if you want them to compost down quicker.

Cork is a “brown” in composting terms – make sure you add some fresh green items (like veg scraps or grass clippings) alongside it to help speed up the composting process.

Most condoms are made from latex (rubber), a natural biodegradable substance, so they will break down in time – but that will take far too long for basic garden compost heap. The latex is often usually adulterated with synthetic materials too – either in the material or due to added lubricants etc – which might slow or impact its decomposition.

Non-latex condoms are typically made from polyurethane – a synthetic non-biodegradable plastic – so they won’t break down at all. Neither will the plastic & foil wrappers that condoms are sealed in prior to use – definitely leave those out of your compost heap too.

(As much as we hate sending things to landfill, the best way to dispose of condoms is simply wrap them in a little tissue paper/toilet roll and throw them in your regular rubbish bin. Flushing them is even worse than trying to compost them. It causes lots of problems in the sewerage process and can, in some circumstances, end up in the sea or rivers with other waste water. They also won’t break down as easily in water – there aren’t enough decomposition microbes around – so they’ll end up bobbing around for years.)

Though wet wipes are usually made from paper (“air-laid” to make it soft, fluffy and absorbent), they sometimes include synthetic fibres to increase softness or durability. Synthetic fibres will not decompose on a compost heap – they will break up rather than break down, leaving lots of tiny synthetic fibres throughout your lovely soil.

The “wet” bit of the wipe is also problematic – depending on the type of wipe, they’re impregnated with various chemicals such as moisturising lotions, detergents or perfumes. Most people do not want unknown chemicals introduced into their compost, especially if they will be using it on veg beds or the like. Anti-bacterial wipes or those containing isopropyl alcohol can also have disrupt the delicate microbes in your compost heap – the ones that are essential for speedy and efficient decomposition.

Finally, items cleaned up using wet wipes can cause composting problems too: oils/greases or dairy products might attract rats or other unwanted visitors to the heap; human fecal matter may introduce nasty pathogens to your compost; cleaning products, especially those containing bleach or other antibacterial properties, can kill off friendly composting bacteria; and finally, things like paint or engine oil can have a serious environmental impact.

As well as not being added to a compost heap, wet wipes should never be flushed down a toilet – they can cause problems for sewerage works as they do not break down like regular toilet paper. If you are worried about the amount of wet wipes you are sending to landfill, consider moving onto washable cloths instead of wipes. Reusable cotton wipes can be composted at the end of their lifespan – which will be a whole lot longer than a single use wipe.

Because the needles are slightly “rubbery” and tough, they’re quite resilient to the usual composting bacteria so take ages to breakdown, and the trunk can take even longer: cutting up the tree or, ideally, shredding it will help a lot. Otherwise, it could easily be next Christmas or the one after that before you start seeing any progress.

You can take advantage of the fact they’re slow to rot down by striping off the needles (if they’ve not already fallen off!) and sprinkling them over muddy paths in the garden. Other people use the bare boned tree to make habitats for wildlife & birds or grow climbing flowers/beans up them.

(One thing to note: It’s a myth that pine needles will make your soil more acidic. Yes, they are generally quite acidic when fresh/on the living tree but by the time you’re ready to compost your Christmas tree, their acidity will have waned considerably: adding fallen/dry needles to your heap won’t disturb the balance too much and once composted, they’ll have little impact on the ph of your soil.)

Alternatively, many councils are happy to take away real Christmas trees as “green waste” (industrial composting processes make short work of the tough trees) and some have even have schemes that use them in local environmental projects. Check your council’s website for details.

Also see: How Can I Recycle Christmas Trees?