Cool-season lawn care calendar

Cool-season grass (tall fescue, bluegrass, ryegrass) runs on the opposite schedule to bermuda and zoysia. Its two strong seasons are spring and especially fall, and summer is survival. The classic mistake is feeding it hard in spring, which produces lush growth that then collapses in July heat.

Pre-emergent (a product that stops weed seeds before they sprout, so it only works ahead of germination) goes down for crabgrass, goosegrass and foxtail, typically best applied in early March. Refine it with your local soil temperature.

If you are also planning to seed this spring, choose one. Pre-emergent stops grass seed from germinating too. This is the most common self-inflicted failure on a cool-season lawn.

Nitrogen stays deliberately light: ⅕ to ½ pound of nitrogen per 1,000 square feet, with the lower end after March 15.

Mowing: 2½ to 3½ inches, every five to seven days by late spring.

Aeration: delay it until fall. Spring aeration opens the canopy right as crabgrass is germinating.

Nothing you do in July makes a cool-season lawn better. The goal is getting it to September alive.

Raise the mower to 3½ inches and cut before it passes 5 inches. Height shades the soil and keeps roots cooler.

Brown patch is the summer disease, developing when ambient temperatures are above 85°F. Keeping the mowing height above 3 inches is part of managing it.

Do not use herbicides at this time. NC State is explicit about it. A heat-stressed cool-season lawn will take damage from the herbicide alongside the weed.

Nitrogen stays at ⅕ to ½ pound per 1,000 square feet if you feed at all.

Water as needed to prevent drought stress. If you have let the lawn go dormant instead, it still needs water roughly every three weeks during a drought to keep the crowns alive.

Grubs: preventive treatment in June; curative treatment works best about 24 hours after significant rainfall.

Fall is when a cool-season lawn is actually built. Seed goes down now, and the heaviest feeding of the year happens now.

Overseeding: 6 pounds of seed per 1,000 square feet. Timing is regional: September 1 to October 1 in the piedmont and coastal plain, and August 15 to September 1 further west.

Nitrogen: 1 pound per 1,000 square feet in mid-September, and again in November.

Mowing comes back down to 2½ to 3 inches.

Aeration belongs here, for lawns on clay soil or with heavy foot traffic.

Work out how many pounds of seed your yard needs with the grass seed calculator, and how much fertilizer hits 1 pound of N with the fertilizer calculator.

Mow to 3 inches and keep leaves and debris cleared. A wet mat of leaves over winter is how you get dead patches in spring.

Apply 1 pound of nitrogen per 1,000 square feet in February.

Treat winter annual broadleaf weeds such as chickweed and henbit as necessary, while they are small.

Rates are nitrogen per 1,000 square feet, from the NC State tall fescue maintenance calendar. Note how the year is weighted: the two big applications are fall and late winter, not spring.

When	Rate
February	1 lb N
March to May (lower end after March 15)	⅕ to ½ lb N
June to August (only if needed)	⅕ to ½ lb N
Mid-September	1 lb N
November	1 lb N

NC State puts the September-through-November total at 2 pounds of nitrogen per 1,000 square feet.

About 1 inch of water every week, soaking in to a depth of 4 to 6 inches.

Through summer, water as needed to prevent drought stress. If you choose to let the lawn go dormant instead, water roughly every three weeks during a drought: that is not to keep it green, it is to keep the crowns alive so it can come back in fall.

Convert that into minutes per zone with the irrigation runtime calculator.