It’s officially October and a blazing 92 degrees just after noon here. We’re setting record highs in New Mexico for heat and have gone weeks without measurable rain in my area while a hurricane threatens additional flooding on the East coast. So I thought I would take a few minutes to review the many uses of fabrics to control heat and retain water in the garden for those of us in drought conditions.
Landscape fabrics, also called geotextiles, typically come in rolls and are available online or in home and garden centers. Nonwoven fabrics are made primarily for weed control. Like plastics, they are the least permeable of fabrics, and should offer better weed control. To me, nothing offers complete weed control. And because they let in little to no sun or water, I would avoid using nonwoven fabrics in beds, at least permanent ones, because they prevent water and oxygen from penetrating. I’d reserve them for walkways only.
Woven fabrics, typically now made of polypropylene, are breathable, which means that water, oxygen and some of the sun’s rays can penetrate. That also means weeds can work their way through, especially since polypropylene tends to eventually break down from ultraviolet rays. Placing organic mulches on top of the permeable fabric introduces more chance for weeds. Still, if you’re adding mulch or gravel above the fabric, it offers an additional layer of protection against weeds. I would selectively lay down woven fabrics for areas of a bed between plants (leaving a large hole cut in the fabric around any plants in the bed) or for temporary uses. Landscape fabrics also can help control erosion on banks, preventing the washing away of top soil. On the other hand, the fabrics never are permanent and if you have a big garden bed, you’re better off investing in extra layers of mulch, which works just as well for weed control if you go three to four inches deep. Just be sure to choose the right mulch for your plant or you cause water and plant health problems.
Row cover is my favorite landscape fabric. Also made of polypropylene, the white fabric comes in varying thicknesses and typically is used to cover and protect plants from frost, such as for mini hoop houses. The fabric lets in up to 70 percent of the sun’s UV rays and some moisture, but doesn’t absorb water. Using row covers can also protect plants from heat by shading roots and blocking wind and insects to some extent. Shading roots and foliage obviously saves water by slowing evaporation. It also keeps the plant healthier, as does controlling insect access. I have begun to use row covers more often this year and have just ordered a roll of the fabric to boost my use more next year, helping to protect young seedlings from insects and to keep the ground warm and moist as they get started.
Here are a few uses for landscape fabrics other than laying them on the ground under mulch:
Although plastic probably works best, lay nonwoven landscape fabric down in the fall after cleaning up your vegetable garden to keep weeds from taking over. You might not choke out every weed, but you can cut down substantially on seeds that blow in and on the sun and rain that help germinate weeds already present. You’ll want to lift the fabric and enrich the soil with organic matter, however, a few months before planting.
Make small hoop houses to cover single herbs or crops. Row covers can help extend the season for a plant, and you also can construct a small, temporary cover over a single plant that’s susceptible to bugs or climate conditions. Or just throw the fabric over a plant in the evening for temporary protection if frost is a concern, but days still produce plenty of warmth.
Use permeable fabric to shade a new plant until it’s established. Around here, we often have to construct cages for small trees and other plants to protect them from deer. Tim has added a fabric top to many to keep the direct sun off a young plant or transplant, which also helps slow water loss. He simply uses cable ties to secure the fabric to the metal fencing.
Finally, since Halloween is just around the corner, you can’t go wrong using leftover black landscape fabric to create a last-minute grim reaper costume. Especially if the weeds are really getting you down….