Every time a sheep is sheared of its wool, part of that fleece is often tossed aside as junk. But that so-called waste wool may be just the thing to increase the health and productivity of garden soil.
Typically the wool from a sheep’s underside and neck area is not worth much because the strands of wool are short and often filled with grass, weeds, dirt and other detritus the sheep picks up in its daily travels. It’s often not worth the time and effort to clean it to the point where it’s usable for fiber.
But take that same waste wool and compress it into small pellets and you have something that holds soil moisture, releases nutrients and repels slugs.
Wool pellets can hold up to 20 times their own weight in water which helps reduce the need for irrigating crops. At the same time, they also wick away any extra water, so they protect plants from any over watering.
Wool is naturally high in nitrogen. Because it takes around six months to break down, it makes wool pellets a good slow-release system for nitrogen. Wool also contains calcium, magnesium and iron, which plants also require.
According to Bruce Hoskins, a soil scientist at the University of Maine, analysis of wool pellets at the university’s analytical lab and soil testing service showed they ran between 9 and 10 percent total nitrogen.
Hoskins said further testing is needed to determine the exact rate at which nitrogen would be released into the soil.
When it comes to pest control the pellets — or even loose fleece — act like a barbed wire fence around plants. That’s because the wool fibers are barbed. It’s why pure wool sweaters itch so much.
If you place wool pellets for fleece around the base of a plant, those barbs will make it very uncomfortable for slugs or snails to get to the stems and will often deter them altogether.
“I think anything you can add to the soil as organic matter that contains fertilizer and holds water is a good thing,” said Dr. Mark King, organic management specialist at the Maine Department of Environmental Protection and director of the Maine Composting School.
“My concern would be any limitations based on what the wool may have been treated with.”
Some sheep ranchers use topical synthetic chemicals in treating their animals for lice, fleas, blowflies, ticks or skin diseases like scabs. Those chemicals can be absorbed by the fleece.
That, King said, could be of great concern, especially to organic farmers.
“Organic farmers are always looking for that one thing that will help increase productivity,” King said. “But they are also the most discerning and will be looking for potential adulterants in the wool.”
King recommends before incorporating wool pellets into a garden, researching where and how they are made to ensure they are organic and chemical free.