During spring and summer, kitchen scraps will break down in about 60 days, giving your soil a boost. If you’re also adding meat scraps and bones, make sure they’re buried at least 12 inches deep, as animals will definitely find them if they’re closer to the surface.
Trench composting is a great strategy to use over the winter if your compost pile is frozen. I can’t bear to waste kitchen scraps (all of that potential nourishment!) and this works very well for me, especially in beds where I grew heavy feeders like corn the previous season. I simply dig a hole in the vegetable bed, pour the scraps in and cover it up with soil and winter mulch (usually straw). I do not include bones or meat, as I have a dog with a super sensory nose who would dig as far as needed to find them, even if they were twenty feet deep. She proved this years ago by digging up a beef bone which she had buried in a flower bed the previous year and I had planted over without realizing it. Good-bye Petunias. I also don’t use trench composting in my flower beds, as I don’t want to disturb any dormant bulbs or perennials that may have re-seeded.
Trench composting is also a great way to replenish the fertility of your vegetable beds in the fall, before you plant a cover crop or cover them with mulch for the winter. By the time you plant the following spring, earthworms and bacteria will have digested the kitchen scraps and your soil will be full of the nutrients your plants require.
This is how composting was done many years ago – the official name is Pit, In-Place or Trench Composting. I was recently reminded of this when I ran into an elderly couple I’m acquainted with. They hail from Germany, are fantastic gardeners and this is the only way they compost and have been doing so their entire lives.