Mulching With Wool: Opportunities to Increase Production and Plant Viability Against Pest Damage

SARE Farmer/Rancher Grant

FNC10-797 Cincinnati, OH – Melinda O’Briant and Katie Charlton-Perkins

Objective: To move unsalable wool from the agricultural waste stream and provide a new market for  growers by using wool as a mulching agent to enhance plant health and increase production of Solanaceae on organic farms.

Results: Turner Farm is a certified-organic farm with about 6 to 8 acres under cultivation. It grows a variety of seasonal vegetables, corn, pumpkins, and flowers, with output distributed to a 50-member CSA. Turner Farm also raises lambs, which involves shearing 40 ewes and three rams, resulting in accumulation of 260 pounds of raw, unsalable wool each year. A small portion of this wool is used for felting classes, but most is stored. We decided to try mulching our crops with it. One pelt covers about 4 square feet of garden at about 4 inches thick.

We experimented with using the wool to mulch eggplants. Initially, we believed the lanolin in the wool might deter the flea beetle, a problematic pest on the farm, by interfering with its breathing. Although beetles did not seem deterred, the plants that received the wool mulch were more resilient than those that received hay mulch. These eggplants also had darker leaves, greater vitality, and higher yield. The soil under the wool mulch seemed cooler than that under hay mulch.

Over the course of our experiment, we measured row production, saved leaves, and took photos to document the differences. Impressed by preliminary results, we further investigated the use of sheep wool as mulch by expanding its use to other plants. Results in 2010 were impressive. A row of sweet potatoes mulched with wool produced 536 pounds compared to just 145 pounds in the row mulched with hay.  The wool row also had less deer damage, which might suggest that it serves as a natural repellent. Overall, all  plants that received wool treatments had on average higher row yield, row weight, and nitrogen content.

In 2011, the average weight and average number of Revolution peppers was highest with the wool-mulch treatment. The same was true for Black Beauty eggplant. Soil-moisture content was higher with both the wool and hay treatments than in the control, or no-mulch, treatment.

Wool had the most insulating effect, with less temperature fluctuation than in hay mulch or no-mulch treatment. Nitrogen levels in the tissue samples were highest in the wool mulch treatment and lowest or deficient in the hay mulch treatment.  Nitrogen levels were lower, but normal, in the control treatment.  To learn more click here.