Organic weed control for lawns

Credit: Flickr / Aaron Tait

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Q: The City of Kamloops has banned the use of pesticides except when applied by a licensed applicator. As I don’t like using pesticides, can you recommend a good organic weed killer for lawns?

There are very few organic weed killers currently registered. Always follow instructions on the label before using. The product names used are just examples and may vary.

“Post-emergence” is where weeds are present. Products are most effective when the weeds are very young. Some weeds are more susceptible than others. Generally this product has no systemic action, i.e., does not absorb into the roots. “Safer’s TopGun,” (potassium salt of fatty acid or soap), or “Eco-Clear” (acetic acid or vinegar) are not selective and could burn everything including your grass. “Sarritor” (Sclerotinia minor, which is a fungi) attacks dandelion, clover and narrow-leaved plantain.

“Pre-emergence” products are used to prevent certain weed seeds from germinating: “TurfMaize” (corn-gluten meal) is used as a general lawn fertilizer but also has some inhibitory qualities on particular seeds, e.g., dandelion, white clover, or large crabgrass. It should be used carefully when re-seeding with grass seed at the same time.

Remember that a thicker lawn generally has very few, if any, weeds. Maintain ideal fertility, and practice infrequent but deep watering, periodic overseeding, and aerating the lawn, and keep to a higher mowing height during hot weather. Lastly, your lawn will benefit from your leaving the grass clippings on the lawn to break down into the soil and add nourishment.

If your lawn needs a “makeover,” dig out weeds by hand, then top dress with at least one to 2.5 cm (1/4 to ½ inch) of a good-quality soil to help even out the lawn and also provide some nourishment. Apply a good-quality grass seed (mainly perennial ryegrass and fescue) over the entire lawn. The grass seed should be applied at the rate 20 to 50 percent heavier than what is recommended on the bag. Use a broom or rake to work the seed into in the soil and existing lawn. Keep moist, watering at least three or four times a day for at least 10 minutes each time. Maintain even moisture for about 14 to 21 days.