Joe Lamp’l, author of The Green Gardener’s Guide and several television gardening programs offers ecologically friendly weed control methods for your lawn or garden.
Solarize the soil. Lamp’l relies on the sun to eliminate weeds. “Solarizing your soil is a great way to control weeds that come up in beds and still preserve the good soil microbes that chemicals can kill,” he says. Clear beds of all vegetation, water generously, and cover with clear plastic sheeting that is 2 to 4 millimeters thick. Secure edges tightly with rocks, blocks or bricks. Let the sun do the rest for four to six weeks during the hottest part of the summer. Intense heat of up to 165 degrees will destroy weed seeds, soil-borne diseases and nematodes.
Corn gluten meal pre-emergent. Corn gluten meal, a byproduct of corn milling, is a natural herbicide that kills weeds after seeds germinate. Apply four to six weeks before seeds emerge. Spread over the turf when forsythia blooms in early spring and again in late summer. This method may require a couple of years to eliminate lawn weeds, and corn gluten can be more expensive than other pre-emergent herbicides. But corn gluten does double duty because it’s also a slow-release, high-nitrogen fertilizer that’s good for the lawn.
Interrupt the growing cycle. Prevent next year’s crop of weeds by removing seed heads this year, says Lynn Jenkins, 68, of Zionsville, Ind., a natural gardening consultant and a habitat steward for the National Wildlife Federation. As Jenkins strolls through her garden, she cuts seed heads before they scatter. “My pockets are always full of weedy blossoms,” she says, noting that you can go back later to dig out the weed.
Vinegar. Inexpensive household vinegar kills weeds and grass between sidewalk seams and in beds. Use a spray bottle to apply vinegar on a sunny day, avoiding any plants that are near the weeds.
Newspapers. To prevent weeds from sprouting, Lamp’l suggests covering the ground between plants with four layers of newspaper and topping with mulch. Wet the papers so they don’t blow away. Use only the black and white newspaper sections, which are printed with nontoxic soy ink. The paper eventually will decompose and improve the soil.