Composting with egg carton and problems with fruit flies

I'm currently renting an apartment in the city where I have a small backyard that measures around 20 x 10 feet that has this really dense clay soil with a lot of rocks and I want to make some raised beds. So I started composting using kitchen scraps and ripped up egg carton plus newspaper. I use an equal ratio of both things and some of the clay soil to cover the kitchen scraps to avoid the bad smells since I don't want my neighbors complaining.

I must admit I've read a lot about composting but am a bit embarrassed to say that all my attempts have failed. This last time I tried composting in a wooden bin that’s like 3x2 feet, but it quickly got infested with fruit flies and I wonder if the egg carton is a good idea since it will probably take longer to decompose and I wouldn't want any nasty Salmonella bacteria or anything like that in it.

I know I have to make a larger pile and increase the brown material but do you guys think that I should just ditch the egg carton all together? Because I don’t have a good source of brown material available, I would have to walk around my neighborhood and look for leaf piles to get a decent amount of it. Also, how do I avoid flies and fruit flies? I had to bury my last attempt to get rid of all the flies.

So since we can't really get away from chemistry, let's look at your pile.  :-)

Composting needs carbon, nitrogen, kitchen scraps, manure (if you have it) water and soil.

You've got egg cartons (carbon) and newspaper (carbon), and nitrogen breaks down carbon.  Wet carbon breaks down faster than dry carbon, so if we find a wet source of nitrogen -- some organic fertilizer from a plant nursery, like a box of Dr. Earth plant fertilizer dissolved in water --  then soaking that carbon in wet nitrogen, putting it over the kitchen scraps.  Or a bag of composted cow manure.   And over the top of all of that put your really great clay soil.  

Lasagna layers.  If you search on Lasagna gardening you'll find lots of great layers of soil amenders and composting ingredients that will work.

Compost wants to be damp, but not wet.  You've also got really great mineral-filled clay soil, so don't despair!  A good three inches of that over the top of your pile will keep the flies to a minimum.  If you are patient enough, you'll notice birds will start hanging around those flies and eat them!

If a pile dries out, it won't compost, so be sure the ingredients are covered and damp.

It's not a fast process, so be patient.

And trust your instincts.  Burying your last attempt is exactly what you should do!

Trench composting is another style.  If you dig out a trench under your raised beds, fill them with scraps, a bag of cow manure, leaves if you've got them, wet carbon (that can even be wet non-treated wood), then fill back over with soil, and plant.  That stuff will be breaking down over the next year, while your other pile is breaking down and can be put on top.

There are a lot of interrelated factors in composting, so it's difficult to advise without knowing exactly your current methods.

You're looking for a carbon:nitrogen (C:N) ratio of about 30:1. You can look up tables online about the C:N ratios of various materials. One potential tricky element of your composting is it's high in kitchen scraps, which are wonderful things, but you've already noticed the problems (pests) that happens when they make up a major portion of your compost. I'd advice adding a large amount of carbon matter (to camouflage the kitchen scraps) AND then adding enough new nitrogen-rich matter to compensate for the extra carbon matter. The egg cartons are a good source of carbon, but not so good at masking the kitchen scraps. In a city I'd guess the easiest to find items would be leaves (carbon/brown) and grass clippings (nitrogen/green).

Lastly you need about a 60%-70% moisture content in your compost pile at all times. If you're in a dry climate, that probably means watering.

If finding the extra brown/green materials is not practical then perhaps forgetting about bin composting and just burying the scraps might be your best bet? But I've never tried trench composting, so I can't offer much advice there, sorry.

Thank you both for your replies! Seems like I accidentally did a sort of trench composting thing and Im thinking of using that space for mediterranean herbs like rosemary and oregano, wonderful! I will definitely use a higher ratio of C:N since it definitely doesn't seem like its enough and the whole idea of dipping the egg carton in nitrogen rich fertilizer is genious! I'm gonna go for both types of composting so I can add amendments to the soil, remove some of the rocks and also get some good soil with composting for some raised beds close to where I placed the kitchen scraps and flies. Thanks a million guys!

hau Mike,

Worms are a great way to take care of kitchen scraps, the bins won't smell when done right and you end up with worm castings, one of the great soil builders.
Instead of using a "fertilizer" use spent coffee grounds, they do the same thing but are cheaper plus they add bacteria, fungi, slime molds to the compost mix, which is a good thing.
Trench composting is a good way to take care of excess kitchen waste but do add enough of the carbon elements or you will have vermin coming for a feast, which might create issues with neighbors.

Redhawk

Compost happens. You don't really need to overthink this and confuse yourself. What you're doing sounds fine, but if it gets stinky or slimy you could collect and add autumn leaves, sawdust, or any other free high-carbon material you can find. Don't tear up the egg cartons: just throw other stuff over them gradually and if you turn your pile later (which isn't necessary but helps), I always find they've turned into nice worm colonies and air pockets. Fruit flies can happen; try covering all food with a dense fly-proof layer of soil of fine sawdust, or a very thick layer of something loose like leaves. Or try keeping a hand trowel next to the bin, and each time you add food scraps, dig a hole down into the finished compost and cover the deposit with finished compost, where compost worms have better access than flying creatures do. But there's gonna be a certain amount of bugs and smell in a compost heap: it is supposed to be a lively ecosystem, right? It's hard because your yard is so small that you can't keep your compost bin far away from the house, where fruit flies don't matter.

Collecting leaves from neighbors is probably helpful. However, collecting grass clippings from other people is risky because weed killers of certain types (aminopyralids) will survive the composting process and will kill anything that isn't a grass-type plant in the later garden where the compost is used. People who manage their lawn organically probably don't put their clippings out with the garbage: they either leave clippings on the lawn while cutting, or they put clippings in their own compost pile; so bagged clippings from neighbors are risky unless you ask detailed questions and trust that aminopyralid weed killers have never been used on the lawn.