Composting worries and troubleshooting


One of the most common things that puts people off starting to compost is the thought of it attracting rodents. 

Compost bins are often blamed for attracting vermin, when in actual fact the rats are already happily living in gardens and allotments.  It is worth assessing if there are other things that are happening in your area that could be attracting rats – for example, garden decking is known to create a perfect home for rats to nest, or if there is lots of rubbish for them to hide in or find food.

There are some things we can do to prevent these local rats seeing our bins as a cosy hotel and restaurant!

Location.  Rats prefer to stay under cover, so ideally place bins away from fences or buildings. Being able to clearly see around the whole base of the bin is useful for checking if there has been any disturbance. 

Bin type.  Use a bin with solid sides, and either place it squarely onto slabs, or line the base with wire mesh to stop rats tunnelling up underneath.  Rats can chew through chicken wire, so some people use a double or triple layer, or a 6mm galvanised mesh is ideal.  I buy mine from Screwfix,and it comes in a pack large enough to line several bins.  (In the photo you can see that a rat has tunnelled underneath on of my Dalek bins, but since they were unable to get in they moved on). 

If you have wooden bays these can also be lined with mesh - it is more cost effective to just line one bay, the one for the freshest ingredients, and leave bays for maturing compost unlined.

Avoiding composting meat and cooked food.  There are ways of composting cooked food and meat etc, however, if you're just started out then it is better to hold off composting these scraps until you have researched how to do this well.  Find out more about these methods here (have links to hot-composting, Bokashi, and Hotbins).

Rat-a-tat-tat.  Disturbing the bins regularly by giving the outside a whack with a stick, or stirring the contents, makes it less appealing to rats looking for a place to settle down.

General good practice, such as keeping areas around bins tidy and free from food scraps, and the composting materialsmoist, all help too.

Bad smells

Finished compost smells beautifully earthy,like a forest floor.  It is a myth that the composting is a smelly process.  However,you may have experienced a slimy, wet, smelly compost bin before learning that you need to add plenty of ‘browns’ into the mix.  If you find you have a smelly compost bin,this is a sign it needs more oxygen and carbon, which is very easy to fix.  Just add in plenty of whatever browns you have to hand – shredded paper, ripped up brown card, woodchips, Autumn leaves - and give it a really good stir, breaking up and clumps of material.  It is sometimes easier to pull out the whole contents of the bin into a wheelbarrow or onto a tarp, and to mix the ingredients all the way through.  You will find that within a week or so that everything is smelling much better! 

Fruit flies

These pesky little flies are completely harmless,but can be annoying when opening your compost bin.  They are part of the natural process, andwill help to break down materials, but there are a few tricks for keeping numbers under control.

- Use a container with a tight fitting lid to collect the food scraps in your kitchen.  Add toilet rolls, torn up egg boxes etc to this tub to help soak up juices. 

- When adding fresh scraps to your compost bin, mix them with brown materials, and cover with a good layer cover to prevent the flies from getting to them.  

- If you do end up with a lot of fruit flies, try leaving the lid off your bin for a few hours.  This will let many of them out, but also let predators, such as birds and beetles, get numbers under control – they provide a helpful snack for lots of garden wildlife! 

Compost taking too long to break down

Check your composter by digging into it, or taking out a handful.  Look at it, notice the smell and texture. 

Think about whether it has enough of the four key composting ingredients: Carbon, nitrogen, water and oxygen. 

Carbon and nitrogen: 

If your compost is slimy and smelly, this is likely due to too many greens.  Add some more browns and give them a good mix.  Check again in a week and add more browns/stir if necessary.

If your pile has a lot of browns that are not breaking down then they might just need watering, or you could try stirring in some more greens, such as grass clippings. 


Do the ‘squeeze test’ to see if your compost materials are damp enough.  It should feel like a wrung out sponge, and hold together when you squeeze it,with just a drop of water being squeezed out. 

If more water comes out, and it feels very squishy, then the pile is probably too wet. This soggy environment is not good for the microbes as it can mean there is not enough little air pockets for oxygen. Add in some more browns and stir.  Check back a week later and add more browns if necessary. 

If does not hold together when squeezed it is probably too dry.  Other signs of a dry pile can be ants nests.  Give it a good water and cover to keep moist e.g. with a tarp or layers of brown card.


Turning your pile will add more oxygen, and speed up the breakdown of materials. 

Size of materials:

A heap full of large chunks of woody materials, sticks, big brassica stalks etc will take a long time to breakdown.  Try removing larger pieces and chop them up with a spade or shears.  

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