Tired of hating weeds in your lawn? Or looking for nontoxic ways to deal with them? Either way, Metro natural gardening expert Carl Grimm can help you find your way to a happier place with your lawn.
We've been trained to hate "weeds"
Moss, dandelions, clover, buttercup and poa annua (annual bluegrass) are often vilified. While they can weaken sports fields, are they really all that bad in a residential lawn? Especially when the American Academy of Pediatrics links lawn chemicals to childhood cancers, behavior disorders, low IQ and asthma?
One alternative: an ecolawn
If starting from scratch, consider buying an ecolawn seed mix that includes turf grass seed and a variety of water-wise flowering plants like yarrow and English daisy. Or you can just choose to embrace some or all of the "weeds" that wander into your yard's turf. My mom's "lawn" has developed over the years into a nice diverse mix of plants that looks good with regular, tight-to-the-ground mowing and infrequent watering.
Tougher turf or a more manicured look will take extra work with or without garden chemicals. Fortunately, many chemical-free techniques will actually save you time.
Simply mowing manages many weeds
Mow 2- 1/2 to 3 inches high about once a week with a sharp-bladed mower and let the clippings lay. Tall grass shades out weed seeds from sprouting. Mowing removes seed heads from taller weeds. The more often you mow (especially in peak growth times in spring and fall), the denser your turf will be. Sharp blades and mulch-mowing (a.k.a. grasscycling) help turf stay healthy and competitive, keeping weeds on the defensive.
Watering just the right amount keeps some weeds at bay
Grass needs about 1 inch of water per week, including rain, to stay strong. Too much water fosters buttercup, moss and poa annua. Too little water thins turf, which lets weeds get a foothold. If your soil has poor drainage, you'll need to water a little at a time and let it soak in between waterings, to prevent runoff.
Good sunlight gives grass the upper hand
Prune branches (or hire a professional to do it) so the sun shines in and "fries" your moss out naturally. If shade's all you'll ever get, consider planting something better-adapted, or spread some mulch.
Hand-pull weeds, root and all
Pre-watering before you weed makes it easier to get the roots out. A Red Pig weeding fork is a formidable digger. Horihori garden knives are favored by many. A nice framing hammer can also do the trick as can the stand-up "dandelion poppers" or "grandpa weeders." But remember to overseed and topdress the holes left behind with weed-free compost to give your grass the upper hand.
Renovate, as needed (in spring or fall), to reap rewards and help keep weeds away
1. Core-aerate lawns suffering from compacted soil using a rented machine, hired service or by hand. This improves drainage and discourages moss, buttercup, poa annua and others.
2. Dethatch with a machine or hand tool to remove some moss and weeds and expose soil for seeding.
3. Overseed with a high-quality seed mix so grass grows in thick and competes well against weeds.
4. Fertilize with a low-phosphorous organic or slow-release fertilizer in May or June and September or October, especially if you need tough or manicured turf. Avoid fertilizing in midsummer as this can stress the lawn. Mulch-mowing reduces fertilizer needs.
5. Topdress with weed-free compost by spreading it 1/4-inch thick to improve soil and turf health.
Get the latest lawn info by calling Metro at 503-234-3000 or visiting oregonmetro.gov/garden.