Composting is a natural process that converts organic waste into a valuable soil amendment. Potato skins are generally acceptable for composting and offer beneficial nutrients to the final product. However, they require specific handling to prevent common composting problems.
Potato Skins as Composting Material
Potato skins and peels are categorized as “green” materials in composting, which means they are a source of nitrogen and moisture. This nitrogen component is necessary to feed the microorganisms that drive the decomposition process in the pile. Along with other fruit and vegetable scraps, potato peels help balance the high-carbon “brown” materials, such as dried leaves or wood chips.
The nitrogen and water content in the skins contributes to the intense microbial activity that generates heat within the compost pile. Temperatures between 130 and 160 degrees Fahrenheit are optimal for efficient and rapid decomposition. Potato skins are also packed with micronutrients like potassium, phosphorus, and magnesium, which are ultimately recycled back into the soil through the finished compost.
Managing Sprouting and Disease Risk
The main concerns when composting potato skins are unintended plant growth and the potential transmission of plant pathogens. Potato skins contain “eyes,” which can sprout into new potato plants if conditions are favorable. If sprouting occurs, the plant slows decomposition and may introduce unwanted potato volunteers into garden beds when the compost is used.
Disease Risk
The risk of disease transmission, specifically late blight, is also a concern. Blight spores can survive on infected material and remain viable in a cold compost pile, threatening susceptible crops like potatoes and tomatoes. Any potato skin exhibiting dark patches, mold, or signs of rot should be excluded from the compost bin entirely.
Solanine Content
Potato skins also contain solanine, a natural toxin that acts as a defense mechanism against pests. Solanine concentration is highest in green parts of the skin or in sprouts. While the toxin is not easily neutralized by cooking, it breaks down over time through microbial action in the compost. Avoid composting green or heavily sprouted skins, or bury them deep in a hot pile to ensure the solanine is degraded before application.
Best Methods for Incorporating Potato Skins
To mitigate the risks of sprouting and disease, preparation is key. Chopping or blending the potato skins into smaller pieces destroys the eyes and significantly increases the surface area for microbes. This accelerates decomposition and reduces the chance of the skins forming a dense, anaerobic layer within the pile.
Once prepared, incorporate the potato skins into the center of an actively working, hot compost pile. Burying the scraps deep within the material ensures they reach the high temperatures needed to kill potential blight spores and degrade solanine. This practice also prevents pests, such as rodents, from being attracted to fresh food scraps on the surface.
Maintain a proper balance of carbon and nitrogen materials when adding potato skins. As a nitrogen-rich “green” material, they must be layered with sufficient “brown” material, such as dried leaves, shredded newspaper, or straw. A carbon-to-nitrogen ratio of roughly 30-to-1 is recommended to promote efficient breakdown and prevent the compost from becoming overly wet or smelly.