A healthy, green lawn is the best form of eco-friendly, natural weed control.
By Melinda Myers
Weeds can be sneaky. They may look small and harmless, but when these opportunistic plants find a weak spot in your grass, they can easily take over your lawn. Luckily, there are lots of natural weed control methods to combat them and insure a greener, healthier lawn that’s not only beautiful, but good for the environment, too.
The grass and thatch layer of a lawn (made up of leaves, stems and roots—some living, some dead) act as a natural filter, helping to keep pollutants out of our groundwater and dust out of the atmosphere. They also reduce erosion, decrease noise and help keep our homes and landscapes cooler in summer.
A healthy lawn is the best defense against weeds, naturally soaking up sunlight, water and nutrients before the weeds can steal them. Weeds appear and spread when the growing conditions are better for them than the grass. Killing them without fixing the underlying cause, however, is only a temporary solution.
If weeds of many different varieties overrun your yard, you likely need to adjust your lawn care practices. To combat the pesky invaders:
- Mow high and often, removing no more than a third of the total height of the grass at one time.
- Leave clippings on the lawn in order to return water, nutrients and organic matter to the soil.
- Apply an organic nitrogen slow-release fertilizer with non-leaching phosphorous, like Milorganite.
Here are a few common lawn weeds, along with their causes and effective ways to control them:
- Knotweed and plantains. Often growing next to walks and drives or other high traffic areas, these weeds also thrive in heavy, compacted soil where lawn grasses fail. To discourage these weeds, reduce soil compaction and improve your lawn’s health with core aeration (punching small holes throughout the lawn to break up compacted soil). Aerate lawns when they’re actively growing in spring or fall. Or replace grass in high-traffic areas with permeable pavers or steppingstones to eliminate the cause.
- Nut sedge. This weed is often found in wet or poorly drained soils. To manage it, improve the drainage by core aerating the lawn and topdressing with compost, regrading the yard, or installing a rain garden to capture, filter and drain excess water back into the ground.
- Clover and black medic. These weeds mean it’s time to get the soil tested and adjust fertilization. Both thrive when the lawn is starving. Clover was once included in lawn mixes because of its ability to capture nitrogen from the atmosphere and add it to the soil. If these weeds are present, boost the lawn’s diet starting in spring with a low nitrogen slow-release fertilizer. It feeds slowly throughout the season, promoting steady growth that is more drought tolerant, disease resistant and better able to outcompete the weeds.
- Creeping Charlie (also known as ground ivy, violets, and plantains). This tenacious weed usually gets a foothold in the shade and then infiltrates the rest of the lawn. Take back those shady spots by growing a more shade-tolerant grass, like the cool season grass, fescue, or warm season St. Augustine grass. Mow high and fertilize less (only 1 to 2 pounds of nitrogen per growing season) than you do in the sunny areas of your lawn. Or replace the lawn with shade-tolerant groundcovers. Adjust your overall care to reclaim and maintain the rest of the lawn.
- Crabgrass and goosegrass. Both crop up following a hot, dry summer. Mow high to shade the soil and prevent many of these annual grass weeds from sprouting. Corn gluten meal is an organic pre-emergent weed killer that can help reduce these and other weeds from sprouting. Apply in spring and fall to reduce weeds by as much as 80% in three years.
And while you’re being green, consider using an electric or push mower to manage your lawn in an even more eco-friendly manner.
About our Guest Expert: Melinda Myers is a nationally known gardening expert, TV/radio host, author and columnist. She is a contributing editor to Birds & Blooms magazine and other publications, and maintains melindamyers.com.
Photography by Melinda Myers, LLC