During the the heat of summer, it’s best to take a tempered approach to weed control on your lawn.
Do: Keep your lawn mowed at a higher length during the summer months. Find your grass on the chart below, then set your mower to the high end of the spectrum when you tackle it. The extra half-inch or inch of height will help shade out weeds and keep your lawn looking beautiful.
Kentucky bluegrass -> 1 1/2″ – 2 1/2″
Fine Fescue -> 2″ – 2 1/2″
Perennial Ryegrass -> 2″ – 2 1/2″
Tall Fescue -> 2 1/2″ – 3″
Zoysiagrass -> 1/2″ – 1″
Bermudagrass -> 1/2″ – 1″
Do: Water your lawn deeply a several times a week, instead of a light sprinkle every day. Deep water saturation is an excellent practice throughout the entire year, since it encourages the development of a strong root system for your grass; it’s also a summer time weed control strategy. Keeping the water below the surface for most of the week can keep conditions inhospitable for weeds.
Don’t: DO NOT apply a chemical fertilizer in July or August. Just don’t do it. Your lawn is already heat-stressed, and your odds of damaging or discoloring your lawn are greater than at other times of year. Just try extirpating most weeds with an herbicide in the early spring or fall months, as advised in this chart created by the Department of Horticulture and Crop Science of the Ohio State University Extension:
Herbicide Name Trade Name CrabgrassFoxtail Goosegrass Barnyardgrass Field Sandbur
benefin Balan G-E F G NA
benefin/trifluralin Team E G G-E NA
bensulide Betasan G-E P-F G-E NA
corn gluten meal Many G NA NA NA
dithiopyr Dimension E G-E G-E NA
oxadiazon Ronstar G E NA G
pendimethalin Pre-MPendulum E E G-E G
prodiamine Barricade E G G NA
siduron Tupersan F-G P-F F-G NA
E=excellent, G=good, F=fair, P=poor, NA=information not available. Exclusion of chemicals or product trade names does not imply criticism, nor does inclusion imply any endorsement, by Colorado State University or the author. Read all label directions before using any pesticide.
While herbicides may be off the table for July and August, any time of year is a good time to get busy with garden gloves and a shovel. Just make sure you drink plenty of water and lather on the sun protection!