Basics On Herbicide Use

Wild Garlic - spring weed

Dandelion

Herbicides are vegetation killers. They kill weeds and occasionally, if applied incorrectly, damage the good plants. A weed is any plant that you don’t want in the garden.

Avoid spraying on windy days or on hot days over 85 °F as chemical herbicides can drift or volatilize, injuring nearby garden plants. Warm summer temperatures increase the possibility of lawn injury from certain herbicides. It should not rain within 24 hours after application. Don't mow a few days before and 2-3 days following an application. Wait 3-4 mowings before treating a newly seeded lawn with any herbicide.

There may be 3 different kinds of weeds you’re trying to control: grasses, broadleaf types and sedges. Broadleaf weeds include dandelions, spotted spurges, buckthorns, purslanes and thistles. Fall and late winter (before new leaves emerge) are safe times to spray broadleaf herbicides. Most deciduous shrubs and trees are shedding their leaves and are less susceptible to the spray drift.

Spring and early summer herbicide applications will not control perennial and woody vegetation such as brambles or poison ivy. Wait until mid-summer to tackle these tough weeds.

For a contact broadleaf  herbicide to work, outdoor temperatures need to be 60 °F and higher over a 6 hour interval for the spray to be absorbed into the plant. Regardless the time of the year, weeds need to be actively growing for herbicides to work.

Finally, heavy weed invasion in lawns may be evidence of poor mowing practices, low soil fertility, or too much shade. Knotweed and spotted surge may indicate bad soil compaction. Tough weeds are not going to give up easily and multiple applications. may be necessary. 

Always read and understand the package directions before using.

Spring Lawn Care Tips

April is time for a minor lawn renovation. All lawn chores should be completed before April 18th, here in the Southern Appalachian region (USDA zones 6a – 7a). If you are planning a major lawn renovation, hold off until September.

Following a rough winter, fertilizing is a positive first step for rapid green recovery and filling in dead spots. Steps for over-seeding small dead areas: 1) light soil tilling with a rake, 2) fertilizing, and 3) seeding.

Over the lawn, apply a crabgrass preventative and again 3 months later (early July). Timing is crucial. When yellow flowering forsythia is passed blooming, crabgrass seedlings have germinated and most preventatives don’t work. Do not apply a crabgrass preventative to recently seeded areas.

Dandelion, henbit, chickweed, wild garlic and other broadleaf weeds are sprayed on non-windy days. Choose a day when air temperatures remain above 60°F for 6 hours or more.

Chart your annual mowing height through the year: first mowing at 1 ½ inches high; after first cut at 2 ½ inches until Memorial Day; during summer at 3 inches; and after Labor Day, back to 2 ½ inches.