Would woven black plastic work for suppressing weeds in an orchard?
Answer: Weed control is a huge challenge for organic growers in any system, but perennial fruits are particularly problematic because it’s difficult to use weed-control techniques like rotations and smother crops without some danger of damaging roots and trees. The use of fabric mulch in high-density orchards is not unusual anymore but it’s widely understood that it’s only effective for two to five years. However, those first few years of a fruit tree’s growth are very important, and suppressing competing weeds during that period is highly desirable. Given the price of weed control, especially organic weed control, the economics of using fabric mulch is competitive. To learn more, consult Weed Barrier Fabric Mulch for Tree & Shrub Plantings from Kansas State University.The reason fabric mulch becomes less effective over time is that blowing mower debris and seed settle on top of the mulch. Subsequently, the weed seed germinates on top of this layer of duff and plant roots eventually penetrate between the weave and weeds become established. Covering the fabric layer with wood chips greatly extends the effectiveness of the fabric mulch. There are different grades of fabric mulch, some seeming more fabric-like and more easily torn, and some thinner or thicker. In my nursery, I’ve used different grades over the years and I’ve come to rely most on heavy, reusable grades like Pro-5, but I pull it up, move it, and re-use it every year or every other year because of the planting cycles of the nursery. In an orchard situation, you wouldn’t have to do that; it would just stay in place.My recommendation is to use a heavy-grade fabric mulch if you’re not going to cover it with wood chips. If you are going to cover with chips, it would not be as important to get the heavy grades; you could go with something cheaper. For more information on managing weeds, check out these ATTRA publications:Sustainable Weed management for Small and Medium-Scale Farmshttps://attra.ncat.org/attra-pub/summaries/summary.php?pub=479Principles of Sustainable Weed Management for Croplandshttps://attra.ncat.org/attra-pub/summaries/summary.php?pub=109