Introduction
While composting is, in principle, straightforward, everyone knows that it’s far too easy to put the wrong thing in and cause a mess in your compost bin for a while.
The “anything organic” principle is a little too simplistic a lot of the time, and that may leave you wondering about certain foods.
We’re going to look at leftover pizza composting (all you need to know).
You can compost leftover pizza, although if you do it a lot (or compost many cooked foods), you may start to encounter problems with rats and other vermin taking an interest in your compost bin.
However, composting leftover pizza is a great way to be eco-friendly and get rid of food waste without sending it to a landfill.

Can I Compost Leftover Pizza?
Yes, you can compost leftover pizza, although if you have had a very heavily meaty or cheesy pizza, you may want to reconsider.
Putting a lot of meat or dairy into your compost bin can cause problems with pests, because these have strong scents and will attract unwanted attention to your compost pile.
Once pests have established that it is a viable source of food, they may stay even if you stop putting out cooked, strong-scented foods.
It is also worth noting that putting meat into your compost can attract flies, which will lay maggots in the meat.
These will quickly hatch into more flies, and the overall result will not be pleasant for you or your neighbors.
You may choose to instead put pizzas that are heavy in meat or dairy into your landfill bin – but you don’t have to.
Burying the pizza in the pile and covering it with dead leaves can help to disguise the smell and deter pests.
However, the problem of pests aside, leftover pizza is absolutely fine to compost, and you won’t have any issue with it breaking down in your compost bin.
After all, it is essentially cooked bread, which decomposes easily, and tomato, which should also break down in very little time.
Toss leftover pizza slices into your compost bin without worrying about it, unless you have a rodent problem.
If you are composting via a council-run service, you may need to check whether you are permitted to add food waste of any kind to the bin.
Some councils do not permit this because of the potential to attract rodents. They only allow for the composting of garden waste.
However, with your own backyard compost pile, there shouldn’t be any issues associated with adding leftover pizza to it in moderation.

Why Should I Compost Leftover Pizza?
You might be wondering why composting leftover pizza should be done at all, especially since it has the negative side of potentially attracting rodents.
However, the benefits of composting pizza cover the same benefits as composting any food – you keep it out of landfill sites and away from the recycling stream.
Pizza definitely doesn’t belong in your recycle bin, so you should never throw it there. It might seem like it won’t do any harm, but actually, it will contaminate recyclables and stop them from being recycled.
For example, many recycling streams are not set up to handle greasy paper properly, and will reject all kinds of contaminated paper and cardboard.
If your leftover pizza ends up landing on some paperwork, that paperwork is no longer recyclable.
This can happen with pretty much any recycling it touches – so don’t put your pizza in your recycle bin!
So, what about the landfill bin?
Organic waste is also very problematic in landfills, because these sites have very little oxygen, and that makes it pretty impossible for the waste to decompose naturally.
Instead, it will be broken down by anaerobic bacteria.
Anaerobic bacteria are problematic because they output large quantities of methane, which contributes to global warming.
Adding food to landfill sites is therefore increasing the environmental problems we are already struggling with.
Another reason to avoid putting food in landfill sites is that they increase the overall amount of space that we need to dedicate to landfills.
Greater volume of waste equals greater demand on the landfills, and although food waste will eventually decompose, it is not in good conditions to do so, and the resulting compost will not get used.
Overall, therefore, putting your pizza in the compost bin is a much more environmentally friendly option.
It reduces the strain on landfills, prevents anaerobic bacteria, and gives you nice, rich compost to use on your garden, pass on to friends, or even sell in the right circumstances.
Composting pizza is definitely a win-win scenario with no real drawbacks!

How Should I Process Leftover Pizza?
Some people will advise you to compost only the crusts of leftover pizza, and throw the rest of the pizza waste into the landfill bin.
This does reduce the problem with rodents, but it isn’t really an eco-friendly option, for the reasons stated above. The majority of the pizza will still end up at a landfill site.
If you have a lot of leftover pizza that needs composting, you may wish to chop it up into small pieces. This will allow you to stir it into the compost and break it up more effectively.
You might also want to freeze some and add it to your compost a little bit at a time to avoid adding too much of any one ingredient.
It’s a good idea to at least think about burying your pizza, especially if you have a problem with rodents or other pest species like raccoons in your area.
You don’t really want to attract visitors to the compost, so if you’re adding cooked food, follow the below steps:
Step One) Scoop off the top layer of your compost pile, making a hollow in the center. It is good to go about a foot down if possible.
Set this material to one side so you can put it back after (it’s often good to scoop it onto a tarpaulin or into a bucket).
Step Two) Tip the chopped-up food scraps into the center of the compost heap. It is a good idea to chop them as this will encourage them to break down quickly.
Step Three) Stir them in a bit to encourage quick decomposition.
Step Four) Replace the removed compost on top to form a layer that will reduce the strength of the smell coming from the cooked food.
Step Five) Add a layer of dry leaves or sawdust on top to further mask the smell if possible. This is the best way to deter rodents and other pests.
Note that this method is not guaranteed to work, but it should at least help!

What Are My Other Options?
If you don’t want to compost your leftover pizza but you also don’t want to put it into your landfill bin, you might be wondering whether you have alternative options that are still reasonably eco-friendly.
There are a couple of other kinds of composting that you can look into that don’t involve leaving the leftover pizza in an exposed outdoor heap.
You could consider Bokashi composting, which uses a special bran to “pickle” the contents and make them unappealing to scavengers. The pickled food can be added to your compost as normal.
Alternatively, consider setting up a wormery. This is an enclosed box that uses worms to break down food waste, and it can be set up in quite a small amount of space – meaning you can keep it inside if necessary.
The worms will eat the food waste and produce husks, which are great for using in the garden.
Worms will process leftover pizza just fine, but be aware that some people suggest not adding meat or dairy to your wormery.
This is usually because it will start to smell quite quickly, and you don’t really want that in your home. You shouldn’t add large quantities of leftover pizza, but a small amount should be fine.
You can also peel off cheese and meat and discard these in the landfill bin if you choose to.
While they won’t do the planet any favours there, this is considerably better than binning the entire pizza slice.
Be aware that worms will also struggle if you give them a lot of greasy food, so try to make leftover pizza additions a rare occurrence.
If the pizza is very dry, soak it before adding it to your wormery or your outdoor compost bin; this will help it to decompose more quickly than if it is left dry.
Summary
You can add leftover pizza to your compost bin, but you should be aware of how often you are doing this and keep an eye on the bin.
If you notice a lot of flies around the heap, you need to bury any meat so that they can’t access it. You may also want to soak the bin to further deter them.
Putting your pizza scraps into your compost rather than the recycling bin or the landfill bin is a much more eco-friendly way of dealing with them, so consider this option – it can definitely be done in small quantities!