Sonoma County organic gardeners share tips for eco-friendly weed removal

There is more than one way to knock down a weed. In fact, there are many methods that vanquish those garden invaders without using chemical herbicides.

Ask an organic gardener what he or she does and they will be apt to say, “I pull them.”

For smaller areas nothing beats putting on garden gloves and pulling. Hand weeding allows you to surgically strike rather than carpet bomb. You also can pull them out by the root so they won’t return.

“The biggest reason I garden organically is my health and the health of my children and my friends,” said Chad Griffith, the assistant general manager of Harmony Farm Supply and Nursery in Sebastopol. “I don’t like chemicals in my yard. I don’t want to expose my children or my pets to strong chemicals. So I’m willing to get on my knees and weed and use something that has much safer ingredients.”

Lena Hahn-Schuman, who has gardened organically in Sonoma County since the 1970s, also weeds by hand. She also recommends sheet mulching. This involves laying down cardboard or newspaper (with black and white ink) over a weedy patch. Deprived of light, the weeds will die. Layer mulch over the cardboard, which will both conceal it, and enrich the soil as the cardboard or newspaper decomposes beneath it.

Another way to combat weeds is to prevent them from growing in the first place. By using drip irrigation, which delivers water only to the plant you want to irrigate, you can prevent weeds from popping up around them, said Hahn-Schuman, who grows organic vegetable and flower starts at her own nursery, Oldies & Goodies in Sebastopol.

She has also tended large estate gardens. At Stone Edge in Sonoma she headed a team that occasionally used Flamers, which are propane-powered torches that scorch weeds to death. They work best on young, annual weeds. Hahn-Schuman said they’re good for driveways. They’re also used on row crops. But exercise caution around anything flammable including structures like your house.

There are a host of hoes and tools to attack weeds. Hahn-Schuman says the Hula Hoe, with its moving rectangular head, is effective, as is the colinear hoe, which skims just below the surface with a very sharp edge.

Griffth said he likes the Hori Hori. It’s a Japanese tool that is a cross between a knife and a trowel. But you have to be able to get down on your knees, and for that he uses a foam pad.

There is a whole assortment of miniature pick axes and other tools that can be applied in different situations to get you beneath the surface to rip those suckers out at the root, he said. Visit a garden center with a good selection and consult a professional on which ones might be most effective for your needs.

No one has yet come up with an organic herbicide, said Rick Williams, Harmony’s proprietor. But there are products known as “knock downs.” They aren’t systemic and won’t penetrate and kill the weed at the root. But they will defoliate the plant, destroying anything visible above ground, Williams said.

The most effective have as an active ingredient d-limonene, derived from orange and lemon peels. One brand Griffth likes is Avenger.

“It’s not a ‘kill everything’ sort of thing,” he said. “It works better if the weeds are in infancy. And it may not be sucessful on wild blackberries or poison oak but it will do a good job on household weeds.”

For larger spaces there is a product called Suppress that is acid-based. But at $280 for 2½ gallons, it’s not cost-effective for home gardens, Griffth said.

Another nontoxic method of weed suppression is landscape fabric, a cloth-like material that comes in rolls that you lay down after clearing the soil. This is good when you want to plant shrubs in specific locations. Plant them in holes cut in the cloth and then spread decomposed granite, mulch or fir bark over it.

“It doesn’t stop every weed,” said Griffith, “but it will make weeding a lot easier once you put it down.”

You can reach Staff Writer Meg McConahey at meg.mcconahey@pressdemocrat.com or 707-521-5204. On Twitter @megmcconahey.