Leaves from broadleaf/deciduous trees tend to compost easily, whether they’re fresh from pruning or have fallen of their own accord.

Fresh green leaves and ones that are brown and soggy from rain or the like compost down the fastest but dried/crunchy leaves often need a bit of a helping hand to actually rot rather than just break into small pieces — stir them into a moist heap to get things moving along.

Leaves add useful bulk to a compost heap but if you’ve got a LOT to get rid of in the autumn, consider collecting them in their own bin, cage or sack – they’ll probably take a little longer to break down than a regular mixed compost heap but the resulting leafmould is a good soil improver, lawn conditioner and mulch (which can be used for weed suppression or for hilling up potatoes etc).

A few warnings about composting leaves

• Some deciduous leaves are tougher than others – for example, sycamore usually take longer to break down than oak. Help them on their way by making sure they’re moist. You can also throw them through a shredder/run them over with a lawnmower – the smaller pieces will break down quicker.
• Holly leaves, rhododendrons, conifers and other evergreens will take a sweet age to break down in a regular compost heap because their leaves are tougher and water-resistant. Either dispose of them through your council’s local green waste service or set up a special slow compost bin that you can forget about for a few years.
• Don’t compost diseased leaves or leaves from diseased trees. The composting cycle might not be hot enough to kill the bugs and the resulting compost might help the disease to keep spreading.

The branches and leaves are very acidic so can upset the balance of your compost heap and later, your soil. The resin can also be toxic, so be careful of that.

Even shredded into small pieces or run over by a lawnmower, conifers take ages and ages to rot down (three to five years isn’t uncommon). (Their acidity and their rubbery leaves make it difficult for composting bacteria to do their magic.)

If you’ve got a lot to get rid of (and if you’ve got leylandii trees, that’s very possible), consider starting a special slow compost heap to avoid interfering with the speed of your normal one. Or find another use for them: some people take advantage of their slow-rotting nature and sprinkle them on muddy garden paths.

Alternatively, you can use your council’s local green waste recycling service to get rid of them: they might be unsuitable for a basic compost heap but industrial composting processes can deal with them much more successfully.

Also see: How can I reuse or recycle leylandii/conifer trees and branches?

The plants are, obviously, just vegetable matter so they will compost down but in a basic garden compost heap, it’s probably better to avoid them.

Tomato vine stems can be a bit tough, so don’t break down as quickly as everything else around it (some people combat this by shredding them first) and seeds from stray tomatoes left on the vines at the time of composting might lead to rogue plants cropping up wherever you spread the compost – if they weren’t worth picking, chances are their children won’t be either.

Most importantly though, most basic compost heaps won’t get hot enough to come close to killing diseases or mould/fungal spores that the plant maybe harbouring. Some problems can linger in the compost for several years, potentially causing serious damage to future crops – not just tomatoes but other plants in the Solanaceae (nightshade) family too (including potatoes, bell peppers and chilli peppers, and aubergines/egg plants).

So in brief, you can compost tomato plants but if you’re new to composting, you’d probably be best not doing so.

Also see: Can I Compost Tomatoes?

They are, of course, just vegetable matter and will rot down fairly quickly. However, like tomato plants, they can harbour diseases/fungal spores that are not completely broken down by the composting cycle, thus potentially damaging future crops. (Not just future potato crops but anything in the Solanaceae family, which include aubergines and peppers as well as tomatoes.)

Little tiny tubers left on the plant also have a tendency to regrow in the warm, nutrient rich conditions of a compost heap – some people like these “volunteer” plants but others think the inconvenience and risk of disease just isn’t worth it.

Many grow-your-own people burn them rather than composting them and some allotment associations have special bins for collecting this type of risky green waste.

In brief, yes, they can technically be composted but in basic heaps, it’s probably not worth the risk.

Also see: Can I Compost Potatoes?

Real wood

Since it is a natural product, real wood will decompose into lovely humus – but anything bigger than twigs will take a LONG time to rot down.

In the meantime, it’ll probably clog up your compost heap, making it difficult to turn over and/or extract other finished compost.

If you do want to compost wood (rather than using it/burning it), it would be better to have a dedicated space for it elsewhere in your garden. In the (many) years it’ll take to rot down, it’ll serve as a playground for all sorts of beneficial insects rather than just getting in your way.

Some councils pick up wood (such as large logs or branches) as part of their green waste collection service. Alternatively, people with wood burning stoves will love to get their hands on your wood (ahem) – offer it on a local noticeboard (either offline or online) and someone will probably be able to collect it within a few days.

Hardboard, plywood, particle board and MDF

Fibreboards are almost definitely a composting no-no.

Hardboard is sometimes just compressed wood fibres – that can be composted – but it sometimes includes resin as a binding agent. As it is hard to tell which is which, it’s probably best to leave it out.

Plywood, particle board and MDF always use synthetic binding agents so dust from those should definitely not be added to a compost heap.

Also see: Composting wood shavings and sawdust

Nettles are considered a natural composting accelerator, especially if you’ve got a “brown“-heavy heap.

You can also use nettles to make a liquid fertiliser for the garden – ferment them in rainwater at a ratio of 10:1 for a few weeks, either in a covered bucket or an old fizzy pop bottle. The result is an iron rich solution that’s great for promoting the growth of green leaves and for building up humus in the soil.

If you are worried about them regrowing or creating a nettle jungle in your garden when you finally use your compost (or using the liquid fertiliser), chop up the plants and avoid composting the roots to get the maximum nettle benefit for the minimum risk.

Away from composting etc, don’t forget that you can also harvest young nettles for use in the kitchen: they can be wilted like spinach or used to make a herbal tea.

Chicken manure is as a useful fertiliser but fresh droppings are considered too “hot” to put straight onto the garden (they are very alkaline and can burn delicate roots and stems). However, it is just fine to add them to a compost heap: by the time the rest of the heap has decomposed, the chicken poo will have calmed down a bit so will feed rather than hurt your plants. (Though still don’t use it on acid-loving plants as it’ll still be more alkaline than they like.)

As always, it’s best to keep your compost heap balanced, made up of a range of different things, rather than just one thing – it’ll produce better compost quicker and with less smell. Since chicken waste is nitrogen-heavy, it is best added alongside “browns“, like wood shavings/sawdust or straw — you know, the type of things that chickens in a coop or run might poop into. If it’s not already mixed in with bedding materials like that, add it to your compost heap in moderation (1 part poo to 4 or 5 parts other stuff) and mix it in well.

Some people with a lot of chickens keep a separate compost bin for just the contents of their chicken coops — the poo, straw/sawdust and stray feathers etc — to create a stronger fertiliser than a general compost. It still needs a while to “cool down” though – about six months, depending on how wet the heap is and how often you turn it.

As the old saying that I just made up goes, ‘one man’s weed is another man’s salad’ so it really depends on what you mean when you say ‘weed’.

It’s really, really important not to compost some pernicious or invasive weeds (see below) but aside from them, you should be ok composting most common weeds – just detach the roots (especially big tap roots) to reduce the chance that they’ll start growing again in the compost heap, and remove seed heads in case the seeds aren’t destroyed during the composting process.

If you are adding lots of weeds, keep the heap well turned and well balanced to ensure it works as efficiently as possible, destroying the weeds before they can spring back to life.

Don’t compost

Other weeds in our database

Duckweed, or water lens/water weed or bayroot, is often the bane of pond owners because oh my, can it spread quickly.

However, it is a great addition to compost heaps – its heavy nitrogen load means it’s a great activator for compost heaps filled with lots of browns, like sawdust, dried leaves or cardboard. (Conversely though, if you’ve got lots of duckweed to do away with, mix it in with some of those browns – it’ll help it rot down quicker.)

Dead slugs and snails

Dead slugs and snails from slug traps or from under your boot can be added to your compost heap.

Their “bodies” will rot down quite quickly due to the high moisture content. Snail shells will take a lot longer – but like egg shells, they’ll break up and disappear into the compost to slowly break down and release their nutrients.

Live slugs and snails

If you prefer not to kill slugs and snails in your garden, you can add them to your compost heap.

As many a hosta or pea plant can testify, snails and slugs eat plants and leaves so can help break down plant matter in a compost heap. They’re not as good as worms but if you don’t fancy killing them after they’ve eaten your lettuce seedlings, harness them for good instead of evil by adding them to your compost bin.

Do keep in mind though that you’re basically giving them a safe place to live and eat – and their children & grandchildren will probably venture back into your garden…