Berry Blankets
Waste wool and wood fiber make a garden-friendly mulch

By Dan Lemke

Morris, Minn. — Wool blankets have been keeping humans warm for centuries. Now they will help grow berries.

The Minnesota Lamb and Wool Producers Association is marketing Woolch, a wool mulch for fruit and vegetable plots and landscaping.

The plush, gray blanket is made from carding waste: low-value fibers often discarded after raw wool is cleaned and separated for spinning. “We have a waste product that does an excellent job on weed control and moisture retention,” says Sherry Stirling, MLWPA secretary and Woolch project coordinator.

“When you’re done with it, the wool mulch can be plowed into the soil where it adds nitrogen, helps to aerate the soil to prevent compaction and is 100-percent biodegradable.”
 

In 1991, the West Central Research and Outreach Center in Morris started testing wool-mulch blankets, which proved effective in controlling weeds, promoting plant rooting and maximizing fruit yields. But the wool had to be trucked to Texas to be needle-punched into blankets, resulting in a $2,000 per acre mulch cost — too high for the market.

In 2004, AURI connected MLWPA with Mat, Inc. of Floodwood, Minn., to create a more
cost-effective mat. After several attempts, the winning design turned out to be a pressed blend of waste wool and wood fiber. It had the first blanket’s characteristics but at a fraction of the cost.

“It turns out the best wool to use was carding waste because of the fiber length,” says Alan Doering, a scientist at AURI’s coproducts lab in Waseca. “That’s good news because they are able to source carding waste from Faribault Woolen Mills. Now there’s a market for the waste wool and the Lamb and Wool Producers are able to produce a blanket that’s cost competitive.”

The new blanket was tested for weed control in strawberries at WCROC in 2004 and 2005. Results showed it as effective as hand weeding and possibly better than standard herbicides.

“There are less than a handful of herbicides that are approved for use on strawberries,” says Steve Poppe, WCROC horticultural scientist. “The wool mulch did what it was supposed to do. Strawberry yields from the test plots were comparable to standard methods.”

Since the wool mulch can be left on plants for two years, it not only helps control weeds and hold moisture, it saves labor. Only the initial planting and mulch placement is labor intensive, then it requires little maintenance. And the mulch is in place during June and July when strawberries must be kept weed free and laborers are busy picking fruit.

Besides strawberries, Stirling says Woolch would work well in tomatoes, specialty crops, landscapes and home gardens.

“Nobody likes to weed gardens,” Stirling says, “but weed control is a huge issue for anyone who raises strawberries, herbs or does any type of truck farming. Unlike plastic sheeting, which has to be taken up and disposed of when it’s done, the Woolch can be plowed back into the soil.”

Woolch is available in rolls that can be cut to fit. An 80 x 5 foot roll costs just under $80.

For more information on Woolch visit www.mlwp.org or call Patricia Anderson at (952) 447-4184.