Compost flies


Compost flies

The dreaded compost flies.

One of the reasons why people avoid anything to do with composting is that they’ve tried it and stopped because of flies. They can be a problem if you don’t manage your compost properly. It’s possible to make compost with just a few flies appearing but not the clouds that some struggle with.

Should you be concerned about flies around your compost bin? Well, don’t panic they aren’t life threatening but yes they are a nuisance. If you want to do something that provides an instant result without using fly-spray chemicals, try hydrated lime. This is a natural approach and the lime will actually help with the overall composting process.

Compost flies can be avoided

You can get a bag of hydrated lime. Make sure that you store this in an airtight plastic bag because a large bag will last some time and if any moisture gets in, the hydrated lime will set hard like concrete.

Orange kitchen bucket by Rolypig


We have a post that explains most of what you need to know about hydrated white lime and how it will improve your compost. You can find it at ‘What does lime do to compost?’.

If clouds of flies appear in large numbers in and around your compost bin or tumbler it clearly means that there is something there that they like. The type of flies that appear will have hatched out from the maggot larvae that thrive in the compost mix.

Pink straight-spout watering can

They will generally stay around the compost bin because this is where their main food source is and they will continue the cycle of breeding to produce more flies.

Don’t allow flies to put you off making compost. You need to be aware that your compost will have a diverse range of life performing within it. Much of it will be so small that it can’t be identified, you won’t even know that they are there. The fact is they are there and it’s a good thing that they are because without them the compost result that we want to achieve probably wouldn’t happen.

About compost flies

If you analysed the living activity, under a microscope, in a compost bin you would find so many life forms that you would lose count. These will include the smallest microbes at one end to worms and, if luck is really in, the largest slugs that you’ll probably ever see at the other.

All of them have an input and provide a combined effect of generating a finished compost. It’s not possible to be selective, nature decides on these things and, by and large, gets it right.

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What else?

How do I get rid of flies in my house?        Carnivorous plants.

Maggots compost bin.                   Does composting attract bugs?

Flies and the Rolypig.

Fruit flies in compost

One type of fly that your are more likely to see are the fruit flies. These are very small and completely harmless. They don’t make any noise but, depending on the scale of the composting operation, there can be a tremendous number of them. As the name indicates these will be found where there is a lot of fruit waste.

Fruit flies in the house

If there are so many that they are troubling you and others, try sprinkling some hydrated lime over the surface of the waste in the bin. This should slow them down and reduce the numbers. You will see fruit flies in a room where there may be a bowl of fruit and one of the pieces has gone a little beyond the ripe stage.

White flies in compost bin

The clouds of flies that occasionally emerge from a compost bin are often mistaken as whiteflies. It is unlikely that you will find whiteflies in a compost bin. They won’t be interested in dead material that is decomposing in the same way that house-flies and fruit-flies do. The adult whiteflies won’t see the contents of a compost bin as being a suitable place for laying their eggs because they prefer the underside of living green leaves.

White flies compost bin

What are white flies attracted to?

The whitefly is more likely to be found in areas where the climate includes a mild winter as they prefer to hibernate on the underside of leaves. In cooler climates they can be found to thrive in glass houses where the temperature is controlled. In the growing seasons they suck the sap from the host plant and produce a sticky residue known as honeydew.

Do white flies hurt plants?

The honeydew residue adversely affects the plant as it encourages fungi which undermines the overall health of the plant. An infestation of whitefly will put such a stress on affected plants that you will notice. The plants will look poor, the leaves will go pale or yellow and become stunted.

House flies in compost bin

These are by far the most nuisance flies of all because, if you get them at all, they tend to turn up in large numbers. These flies make the fruit flies look tame. A compost heap that isn’t being managed properly will provide an excellent breeding place for the house fly.

As the name suggests as soon as they’re airborne they head straight for the house with the specific intention of pitching on your food and, where possible, on you. When you consider where they have come from and where they have been, this should be enough to want to get rid of them and prevent an infestation being generated by your compost bin.

But there is more. When they pitch on your food they aren’t contented with just wiping their dirty feet, they like to have a feed as well. This doesn’t mean taking a bite and flying off. Their’s is a much more elaborate feeding process.

House flies on food

They will excrete digestive juices on to the food to dissolve their intended meal and then suck it up like a vacuum cleaner. So if you want just one good reason for getting rid of flies there it is.

How do I get rid of flies in my house?

There are ways of catching flies in the house. There are sticky fly-catchers which do work really well but you need to know that they will stick to you and anything else if you forget that they are there when moving around. 

If you want something that is more high-tech and totally decisive then there are electric fly-catchers. These have a fluorescent light that draws the fly in and then zaps them with a killer electric shock. You will very often see industrial versions of this in food-shops. 

Another option is to have a [fly zapper racket. These look as though they are for tennis but they are highly effective at killing flies in mid flight. It takes a little practice to start with but you can quickly clear a room with it. It’s also highly successful at zapping wasps but make sure you finish them off because these can sometimes be just stunned leaving them to become crawlers. The same applies to hornets.

There is just one more way of swatting flies and that is using your bear hands. This could be described as an art. When you see a fly pitched on a surface of, for example, a table, move in as close as you can with your hands in the ‘ready-to-clap’ position. The aim here is to clap your hands just above where the fly is pitched.

The idea being that in the split second when the fly takes off at the moment you clap your hands the fly will fly up and into the space where your hands will slap together. You have to think about where the fly will be in the fraction of a second that it will take to become airborne as soon as you begin your clap movement.

This takes practice but you will see, after a while, how to predict what the fly will do. You will be catching flies between your clapped-hands like fun and I know from experience that you can clear a room of every single fly in a short space of time. Remember to wash your hands after you’ve had a session catching flies this way.

Carnivorous plants

There is one more way to catch flies. This one is a bit of a novelty and rather exotic. There are carnivorous fly-trapping plants. Among these are the venus fly-trap and the pitcher plant. You need to know that, unless you have a significant number of plants, this is in no-way an industrial method of catching flies. But it’s nice to know that you have a natural system in place that is quietly dealing with the occasional fly in the background.



Maggots compost bin

You have to except that there will be many types of life in your compost bin and that, as long as you are aware that all of them play a part in making compost, these life forms are of use. You have a load of green kitchen waste which you want to see convert into compost. For this we rely on nature and whatever steps up to the plate is what nature provides, we can’t be picky about it.

However when it come to maggots it can only mean one thing, when maggots go through their final stage of metamorphosis there will be flies. Not just a few but clouds of them. They make tending to the compost bin an uncomfortable chore and when you go near them they will take a liking to you and start following you around. They will find their way into the house where the story continues.

I think we can all agree that out of all the creepy-crawlies that live in a compost bin of any type, we can manage without the maggots. So how do we get rid of them or, better still, prevent them from starting? If maggots turn up it can be taken as an indication that other factors are at play which shouldn’t be there. In short, if you have maggots in the compost bin it’s probably because the compost is too wet and acidic.

There are two things you can do to address this problem. The first is to add some drier material in the form of shredded paper or cardboard. The second is to add hydrated lime, this will reduce the acid level. The cardboard or paper will add carbon to the mix which will balance the nitrate level which will be higher than it should be if the mix is wet.

Adding these two components will not only reduce the maggot and fly problem but it will also reduce the smell which often accompanies wet compost that is effectively stagnating and not converting to compost. It shouldn’t be necessary to use any chemicals to remove maggots. While they are there they are actually doing some good in breaking down organic material. It’s only when they hatch out and fly off that they start to be trouble.

Does composting attract bugs?

Yes it does. You will never know how many life forms will take up residence in your compost bin. A micro environment where organic material is breaking down may look a total mess to us in our clean, tidy and ordered world. To the plethora of microscopic and not so microscopic beings this is their heaven.

Of course we need to be aware that peace is not a natural state among these creatures and that there will be those that seek to eat others. This is nature at work from which the combined effect is that compost is generated.

Should we be concerned about the types of bugs and life forms that live in the compost bin? No. Everything that lives in a compost bin is there to feed on the nutritional value that the rotting material has in it before it’s fully converted to finished compost. When the composting process is complete and there is nothing left of value to take, then most of the life forms will either die off or leave to find nourishment from elsewhere.

Is vinegar good for compost?

If anyone is thinking of putting vinegar on compost, don’t. This would be a total waste of vinegar. Compost will not benefit from vinegar in any way. Vinegar is associated with preserving foods or flavouring. The whole point of making compost is to do the opposite of preserving and break down food waste into a finished usable compost.

The other issue with adding vinegar to compost is that vinegar is acidic. Compost, through the nature of decomposition, tends to be acidic. The composting process will be accelerated if we can reduce the acid, so we must avoid adding to it.

This is where the adding of hydrated lime makes a big difference. This will reduce the acid level or bring up the ph level to a neutral point where decomposition can proceed efficiently.

Hindering the process of food-waste converting to compost will provide an opportunity for the flies to prosper. They are going to be attracted to food that is being preserved rather than food that has been broken down through an efficient composting process.

This is where the adding of hydrated lime makes a big difference. This will reduce the acid level or bring up the ph level to a neutral point where decomposition can proceed efficiently.

Will there be flies in a Rolypig composter?

Yes, if you don’t take the precaution of doing all the things that need to be done to reduce the acidity and moisture levels there will be flies. When feeding the Rolypig, add about one tablespoon of hydrated lime. This will mix into the compost. If the waste being fed looks wet then add some pieces of cardboard and or shredded newspaper. Doing these simple things will almost guarantee successful compost from a Rolypig without being troubled by flies.

Compost tumbler

A good indication that you’re doing everything right is seeing a strong population of worms that have moved in, by choice. If the Rolypig is on a site where there are no worms or the wrong type of worms, you can import worms but if you do this there must be enough ready-made compost for them to feed on. Find out more about the Rolypig at

Find out more about making compost from things that may attract flies, see: can you put cooked meat in compost?

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 Find out about 'Brown' material in compost. What to put in compost bin to start.  Can you use compost for growing vegetables?

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