Emily Tepe, University of Minnesota Research Fellow
If you grow strawberries you are familiar with the spring and summer task of crawling through the rows pulling weeds. It’s a time consuming, arduous task, but a very necessary one. Weeds rob strawberries of valuable water and nutrients, resulting in reduced vigor and fewer, smaller berries. Hand weeding is just about the only way to remove weeds in a strawberry plot because mechanical removal can easily damage the low growing strawberry plants, and approved herbicides are declining in number and becoming more and more expensive. Additionally, consumer interest in local foods grown without such chemicals is rapidly increasing, leading growers to look for alternatives. So with few options other than growing strawberries with plastic mulch (which poses its own environmental problems), growers get on their hands and knees each year in an endless battle against the unrelenting weeds.
But now there is hope for the achy knees, sore backs, and tight schedules of strawberry growers. Wool mulch, cleverly named Woolch™, is marketed by the Minnesota Lamb and Wool Producers Association and has been studied for the past ten years at the University of Minnesota West Central Research and Outreach Center in Morris, and at several local farms. The results of 10 years of trials have shown overwhelming success of Woolch™ in reducing weeds in strawberry plots.
Photo 1: Rolls of wool mulch. Emily Hoover
Photo 2: A row of strawberries growing through wool mulch. Emily Tepe
Woolch™ is a value-added product of the Minnesota lamb and wool industry. It is manufactured using short fiber waste wool from the carding process, in which raw wool is cleaned and separated before spinning. Similar short fiber waste wool is collected from the napping process of blanket-making at local woolen mills. These short fibers are combined with wood shavings from Minnesota timber mills through a heat and roller process, and the result is a lightweight felt-like mat that is completely natural and biodegradable.
Woolch™ works well with strawberries for several reasons. First, water and nutrients can move through it, daughter plants can root through it, but weeds neither grow up nor root down through it (except for quackgrass, which should be eliminated before planting). Second, it helps maintain soil moisture and moderates soil temperature. Third, it creates a barrier between the low growing strawberry and the soil which may harbor fungal diseases that can lead to reduced growth, poor yields and damaged fruit. In a similar vein, berries resting on Woolch™ remain cleaner and drier than those conventionally grown. Finally, Woolch™ breaks down over a couple of years, meaning it can then be tilled into the soil to add valuable nutrients.
Photo 3: Wool mulch in the garden keeps the soil moist and cool, and deters weeds. Emily Tepe
Though not part of any research project, I can personally vouch for the success of Woolch™ in the home garden. Last season I planted vegetables and flowers in a veritable weed patch, and I expected to spend the summer battling the continual onslaught of weeds. Not this gardener! I ran a soaker hose throughout the beds to allow for direct and easy watering. I then cut pieces of Woolch™ to place around the plants, and cut slits to fit pieces around stems or rows of stems. I shoveled a bit of soil over the edges to keep the Woolch™ in place, and gave it a good watering from above to help it adhere to the soil. Throughout the season the soil remained moist and cool under the Woolch™, and the plants were vigorous and abundant. The only weeding I had to do was is in the paths between beds, which was quick and easy. This season Woolch™ will be used in a new edible landscape planting in the beds outside the Plant Growth Facility on the St. Paul Campus. Stop by and take a look at this innovative, effective, and totally natural product in action!
Photo 4: Fitting wool mulch around the stems of plants like this pepper keeps weeds at bay and helps hold moisture in the soil. Emily Tepe
Woolch™ is available directly from the Minnesota Lamb and Wool Producers Association. For more information visit their website at http://www.mlwp.org/woolch.htm. You can support this local industry while benefiting your garden or small farming operation!