We received a query on the Garden’s Grace Facebook page a few days ago from a gardener wondering how to fight weeds without herbicides. Not only is chemical-free weeding possible, but there are also many techniques for preventing weeds in the first place! Here is a quick run-down of the top methods for preventing and killing weeds in your ornamental or vegetable gardens.
- This one will shock you–quit tilling! As a kid, it was our family’s right of passage to follow behind my Dad as he tilled the rich black soil of our northeastern Iowa veggie garden. Why isn’t this the greatest idea? Because as we are tilling under seeds from last year’s garden,we are also bringing seeds to the surface from as much as ten years ago! The “weed seed bank” is rich, and once those seeds are exposed to sunlight, they are ready to get growing! If you cultivate, cultivate shallowly, as one would with a hoe. That way, you are destroying new weed seedlings without bringing a whole lot of dormant seeds to the surface.
- In your ornamental and perennial beds, vary your method for weeding with the type of weed you are removing. For deep, tap-rooted weeds like dandelions or tree seedlings, use a trowel or narrow weeder that can pierce the soil and lift all or most of the root. Sometimes, loosening the soil around the weed can help the whole root be lifted without breaking.
- Use weed fabric, organic mulch or other materials to smother weeds and prevent sunlight from hitting the ground where weed seeds live. Make sure if you are using wood mulch, that it has been seasoned (aged) so that it won’t be robbing nitrogen from your soil. That means if a friend offers you wood chips from a tree they downed, let them sit for at least a year before using them on your beds.
- Use an organic pre-emergent like corn gluten (available commercially by many makers). This is a double winner for we Iowans–the seed-germinating inhibition of corn gluten, a by-product of corn processing, was discovered by Dr. Nick Christians at our own Iowa State University. An added bonus is that corn gluten has a small amount of nitrogen which will benefit the desirable plants in your garden.
- Cultivate healthy plants, especially in lawns and ornamental gardens. Well-grown lawns are never cut shorter and three inches and are over-seeded as needed to maintain a nice lush stand of turf. As the saying goes, “Nature abhors a vacuum,” so open spaces are likely footholds for weeds to grow. The same goes for your ornamental gardens. Healthy plants compete better with weeds, and well-planned gardens often are designed to shade out most open areas, and with them, shade out weeds.
- For driveways and patios, check out the method called “flame weeding.” The tool looks much like a cane with an end to attach a small propane tank. The key to flame weeding is not to torch the plants entirely, but apply heat until the tissue starts to “bubble” a bit. This triggers a response in the plant that shuts off the root from the rest of the plant, thus killing the top of the weed. Always use care not to flame weed near flammable materials like dry leaves or grass.
- Look for recipes for home-made weed-killers that use things like vinegar or borax. Vinegar basically disrupts the acidity of the weed’s root zone, causing it to die. Borax is often used in solution against creeping charlie or ground ivy. Always follow the directions–applying incorrectly can also kill your desirable plants.
These aren’t brain surgery, but they are all methods that have been studies and recommended by horticulture professors and experts throughout the country. Try some yourselves, and enjoy a garden that is beautiful and relatively weed-free! If you need help taming the weeds in your garden, call Garden’s Grace today–they have skilled gardeners that can get things under control in very environmentally friendly ways.
Blog written by Anne Larson, Des Moines area horticulturist and writer for Iowa Gardener Magazine, and a weekend associate with Miller Nursery.