Compost bin infested with flies

[caribumamba]

I have a compost bin at my mum's and looked to add some today and it was teaming with flies. I am talking like a carpet of black flies. This is in an old water but with the top cut off to form similar to a usual
compost bin of open top and bottom. There is still a lid but there is a hole in the lid where they can get in easily.

On the other hand at my own place I have an open air pile and haven't noticed flies build up substantially. I am wondering why the difference. Is it due to the wrong mixture? too much old foodstuffs without stuff like leaves and grass?

I actually don't have much of a mix in mine up there either, the open air seems to be doing something to mitigate them then.

Oh and my mum has a bin of her own which she puts only food in I think but the lid is sealed and no big flies like I have, just those little ones about the size of a pinhead, so I guess either have proper mix of materials and/or have it covered.

I know they are supposed to be beneficial to the composting process as well but there are so many they will become a nuisance I guess being so close to the house due to teaming population. I haven't told her yet, hehe. She is probably not going to be happy about that. How to mitigate the current issue? Should I just close the lid and trap those existing ones? I don't like killing stuff, even flies, en masse. Even if I did the bin would provide everything they want in there to keep multiplying and maybe make it worse as they wouldn't be able to fly out so next time I opened it they would swarm out!

Maybe just add some weeds which they are probably less fond of until it balances out? perhaps more water too to make it less favorable for them in there?

[mothhawk]

Leave the lid off so they can get out. The reason you don't see them on the open air pile is that as soon as they emerge they can fly off. Or get eaten by birds, frogs, toads and such.They mate almost as soon as they can fly, so if you close the lid you are simply imprisoning loads of pregnant females, who will lay their eggs in the compost and continue the cycle instead of flying off to lay elsewhere or get eaten by other creatures.

[caribumamba]

Leave the lid off so they can get out. The reason you don't see them on the open air pile is that as soon as they emerge they can fly off. Or get eaten by birds, frogs, toads and such.They mate almost as soon as they can fly, so if you close the lid you are simply imprisoning loads of pregnant females, who will lay their eggs in the compost and continue the cycle instead of flying off to lay elsewhere or get eaten by other creatures.

Yes but they can get out, the same way they got in. There is a hole about the same size as the mouth of a cup.

[Andraste]

I've experienced this after adding a log of fruit waste (banana skins etc.). Rebalancing by adding browns (e.g. shredded newspaper, cardboard) may help.

[JoaoLeaftide]

Adding browns is the right call. Flies tend to build up when there's too much wet green stuff and not enough carbon to balance it. Shredded cardboard or dry leaves mixed in usually sorts it out pretty quickly.

[ChingfordHarry]

Yes but they can get out, the same way they got in. There is a hole about the same size as the mouth of a cup.

Have you ever noticed that houseflies that come into your house will never leave the way they come in? Their minds don't work in the same way ours do...

[mothhawk]

Yes but they can get out, the same way they got in. There is a hole about the same size as the mouth of a cup.

Flies are stupid. Ever tried to get a blowfly out of the wide open door it came in through?

[caribumamba]

Flies are stupid. Ever tried to get a blowfly out of the wide open door it came in through?

I took a look inside yesterday and they were all dead, well nearly all. It was like carnage, poor things, but I am sure they meet many other similar fates all the time too.

I don't get how they were all alive then all dead, as in not an ebb and flow but they all ceeased around the same time and no new ones alive in there.

Another thing I noticed is that there were a few outside the bin which were unable to fly. I wonder if the ones inside couldn't fly either. I had left a stick in the bin coming out the hole just as good practice for any creature to get out if it fell in and when they were alive when I checked before loads were trying to climb up the stick but when I looked yesterday no more since they were dead. I wonder if the ones outside had managed to climb out.

They were only able to fly a few cms off the ground then crash back down and spin about a bit on the floor only to try again.

Any idea why? Were they mutants? or like the pigeon parlour rolloers who can't fly either?

Also why would they have died? I would have thought there would be enough food and moisture from the food to sustain them indefinitely. Maybe it was the lack of moisture as the compost was rather dry but I would think that flies won't need much. I threw a couple of buckets of water into the pile to get its moisture back up.

[Andraste]

most little flies/gnats have a very short lifespan - or they could have cooked in the heat of the compost bin in this weather