Weeds in your Lawn? Here are some Possible Solutions.
by Priscilla Williams and Michael Nadeau

Weeds are tolerated in an organic lawn to varying degrees. Many so-called “weeds” are beneficial to the lawn ecosystem so you may want to learn to accept them. It wasn’t until the advent of selective herbicides about 50 years ago that a lawn consisted of only grasses. Before that, any plant that lived under the mower blade was considered “lawn.” This diversity of species led to lawns which were more tolerant of adverse conditions.

Often excess weeds are a symptom of poor soil, a flag that lets you know a pH adjustment is needed. Check the pH of the soil first and with the proper adjustment you may get satisfactory weed control. Healthy turf and weeds cannot co-exist. The turf will shade and crowd out the weeds.

In some cases, weeds can get out of hand and take over sections of lawn. A popular organic control method is corn gluten meal which acts as a pre-emergent weed control by preventing the germination of weed seeds. It is applied in the spring between forsythia and lilac bloom, before weeds such as crabgrass emerge. It can be reapplied in early summer to prevent germination of late-season weed seeds.

Because corn gluten meal is high in protein, it contains approximately 10 percent organic nitrogen. This nitrogen level needs to be accounted for in the overall lawn management program so that nitrogen is not over applied during the season through additional fertilizer and compost applications, for example. Also realize that if you spread corn gluten after the weeds have germinated you’ll simply be fertilizing them.

To deal with the bare spots left behind by corn gluten treatments, plant an annual rye grass to “hold the spot” until a perennial lawn seed mixture can be established in the fall. Mix the seed with compost and spread it at least two inches thick in the bare areas.

Corn gluten meal is also effective in weedy flower beds. Dust the meal on the bed as if it were salt and pepper hitting the dinner plate. It doesn’t matter if the corn gluten contacts foliage. It only has pre-emergent properties, not post-emergent. During the first season of use, apply the corn gluten meal again to the bed in the fall once the weeds have died back for winter.

Unwanted weeds that exist in the lawn or garden, such as plantain or dandelions, can be organically controlled with the use of non-selective herbicides made from the essences of vinegar and lemon juice (ethanoic and acetic acids) or potassium salts. The weeds are cautiously spot sprayed, being careful to avoid any unnecessary over-spray or drift onto desirable lawn or plants. Two good products for this purpose are Burn Out™ and Scythe™. As with all chemicals, always read the directions carefully before use.

Dandelions can also be physically removed with a two pronged metal hand tool which digs up the tap root. A few dandelions can also be left in the lawn to add to a healthy diversity of plants. Dandelion leaves and flower tops are edible, and in fact, dandelions are produced commercially and sold as edible greens. Commercial dandelion farmers’ worst enemy is turf grass because an established turf, mown tall, will out-compete dandelions .