Certainly. Any time you do something to introduce disease pathogens into your garden you need to be concerned. Your winters are no more cold and snowy than mine here on the west coast of Michigan and I have had no trouble composting above ground during the 50 or so winters I have been doing this, except the first few years it took me to learn composting.

That small volume container would be more apt to freeze, above ground, but even that if the material is just moist and not wet should continue being digested all winter.

kimmq is kimmsr

So how do I know if there are pathogens in the compost in May, or what can I do to kill them? It will be in the container for 7 months. Is that not long enough to kill all the pathogens and diseases?

I am in 4b here in central MN, and we get plenty cold, with extended periods of below zero f temps for days to weeks on end every winter.

There are two 4' X 4' sections of my garden where every year I pile up all my grass clippings, kitchen scraps, chopped up spent plants form the year's garden, and fall leaves mixed with grass that I collect until I stop mowing sometime in early to mid October. I chop up my final leaves, with my blower/vacuum, and cover all my beds with this mulch at the very end of the season before freeze up. Every year I move my piles to a different section of the garden.

My compost is pretty anaerobic because I just dump it and forget it. By the following spring it ready to added to my beds. The amount of earthworms and my garden growth is outstanding and far surpasses any other vegetable garden I know of in my area…I attribute much of my success to this method.

As soon as I start mowing in the spring, I start to whole process over again.

My concern is that anaerobic method might not kill all parasites and pathogens. But if I'm only using kitchen waste (fruits/vegs), non-disease plants/leaves and cardboard/paper, there would little to no chance that parasites and pathogens would show up, right? If people are directly burying greens and browns in their ground, that's pretty much anaerobic.

The only way you will know if that compost has diseases pathogens present or not is by microscopic examination. The anaerobic composting does not, will not, kill off any disease pathogens and will encourage them to grow. Your kitchen waste has these disease pathogens already present and they are all around you to be picked up at any time.

The description of composting by tbenjr above does not sound like anything close to an anaerobic (in the absence of air) process, it does sound quite normal and aerobic.

kimmq is kimmsr

That is good to know Kimmq.

I suppose I could turn my piles and make my process faster by letting in more air.

50 x 50 is not a large container in composting terms. It's actually rather small and it hardly seems worth the effort of digging a hole for it. Was that size governed by the amount of material you could find to compost? I'm curious as to the reasoning behind making the process more complicated than it need be. And there is no need to add soil to a compost heap.

Because it is a container and if I were to make holes, it would break, so I prefer to use the anaerobic method. It's now fall and I don't want go outside in the cold, turn the compost, etc. I'm also new to composting. I read you had to add some ground soil to introduce some bacteria to the mix.

kimmq,
I read that it would take between 6 months and 1 year to eliminate the pathogens using the anaerobic method because the environment becomes inhospitable.

If I dig a trench and bury the browns/greens in the soil, that would be aerobic composting? Even if the brown/greens are covered by soil, they still have access to air? So if I leave the my container open (with soil on the top), that would be aerobic composting? And it would still work during winter?

There is a spectrum of methods between anaerobic and aerobic with intensive turning. Many of us just pile it up and let it rot, turning only when we move the heap into the next bin to start a new one. Any method which doesn't seal the container hermetically will be aerobic and it is possible to produce compost aerobically without turning. If you do manage to really seal your container I think you'll end up with a box of slime rather than compost. If you can't seal it completely then it will decompose aerobically.

There is plenty of air in the soil so trench composting is indeed aerobic.

So I can simply bury the container in the ground, and leave it uncovered? Rain and snow would fall on it (there is a hole at the bottom). If there is 20 inches of snow on top of it, it would be still be composting aerobically?

Yes it would. And if there is a hole in the bottom, even if covered it would be aerobic.

50 cm is not quite 20 inches, about 1 - 3/4 feet. A very small volume that will not allow the bacteria that will be digesting the material enough volume to generate the heat needed to kill off potential disease pathogens. I would be less concerned about any potential disease pathogens that might cause plant diseases than I would be about potential disease pathogens that could infect people.

kimmq is kimmsr

If you really want to compost by putting things in a bucket and forgettng about it for a while, look into bokashi.