Potato skins that will not decompose

Asked April 23, 2019, 3:58 PM EDT

The sweet and white potato skins that I buried in October are not rotting with the other vegetable matter that I put into my compost. The skins appear as fresh as when I first buried them. There are huge earthworms moving in the decomposing coffee grounds and other vegetable matter. Is it possible that the skins were treated with preservatives?

Baltimore Maryland

3 Responses

Hi- anti-sprouting chemicals are routinely applied to white potato and sweet potato crops after harvest to prevent sprouting. However, these compounds decompose when exposed to soil microbes, water, and air. It is odd that the skins survived intact for 6 months in a compost pile. Washing/scrubbing your potatoes prior to peeling will remove the chemical.

We recommend that store-bought potato scraps not be buried in garden soil because there is a risk they carry pathogens (such as late blight) that could infect garden crops in the potato family.

Are there any reasons that explain why the skins did not decompose?
You referenced anti sprouting chemicals.

I eventually took a shovel and chopped the skins into the soil and mixed
them with rotting leaves and placed that mixture in a different compost.

It's possible that the skins were in a protected location within the pile where microorganisms could not thrive- too wet, too dry, too much space between pile constituents, not enough air or high carbon materials.