Lawn care calendar for Nebraska: when to fertilize and seed

Fertilizer rates are pounds of nitrogen per 1,000 square feet from the NebGuide tables; the older-lawn column in the guide gives no or 0.25 pound in spring and October.

Which grasses grow where in Nebraska

Nebraska Extension’s lawn calendars cover Kentucky bluegrass, tall fescue and other cool-season grasses such as perennial ryegrass and fine fescues, which make up most lawns. Its separate NebGuide for warm-season lawns covers buffalograss and zoysiagrass, which are not fed, mowed or watered in early spring.

The guide splits the advice by lawn age: newer lawns, under about 20 years old, often struggle in soil low in nutrients with high weed pressure, while older lawns need less fertilizer and have lower weed pressure. That is why the same date can mean 1 pound of nitrogen on a new lawn and nothing on a mature one.

Frost dates from NOAA

Dates are the NOAA 1991-2020 normals for the last spring and first fall 32 F freeze at 50% probability. Omaha Eppley Airfield averages April 18 and October 21, Lincoln Municipal Airport April 24 and October 13, Scottsbluff Heilig Field May 5 and October 4, and North Platte Regional Airport May 11 and October 1.

Counting the days gives about 186 frost-free days in Omaha, 172 in Lincoln, 152 in Scottsbluff and 143 in North Platte (our arithmetic). North Platte has about two months less than Omaha, which fits the western calendar starting its first feeding a week or so later than the eastern one.

Spring

Both calendars begin mowing in April at 3 to 3.5 inches for the whole summer, never taking more than a third of the leaf at once. The first feeding for newer lawns is 0.75 to 1 pound of nitrogen, combined with a preemergence herbicide when the soil 4 inches down reaches 55 F. Older lawns can skip it, or take up to 0.25 pound, if color and density are fine.

Aeration with hollow tines and summer patch prevention are paired with the first feeding for lawns that need them. The guide says to apply fungicide for summer patch when the 2-inch soil reaches 65 F, only on lawns with a history of the disease, and to repeat it four weeks later. Spring overseeding runs April 25 to May 15, with core aeration before or power raking after for seed-to-soil contact.

Summer

Early June brings the second preemergence herbicide and a 0.5 pound feeding for all ages of lawn (June 1 to 15 in the east, June 10 to 20 in the west). The calendar says a lawn needs 1 inch of water a week from June to September, including rain, and that overwatering weakens turf. Scouting for dollar spot and brown patch is advised, but fungicides are not usually recommended for home lawns.

For buffalograss and zoysiagrass, the warm-season NebGuide says to mow 2.5 to 3.5 inches all season and that more problems arise from overwatering than underwatering. It puts 1 pound of nitrogen per 1,000 square feet after green-up in May or June and a second 1 pound in July or August, with no fertilizer from September to February and none in early spring.

Fall

Fall does the most for a cool-season lawn. Overseed August 15 to September 15 in the east and August 15 to September 5 in the west, and feed newer lawns 0.75 to 1 pound of nitrogen from late August. Older lawns get one fall application of 0.5 to 1 pound around September 15, with 30 to 50 percent quick-release nitrogen. Nebraska Extension’s 2026 fertilization article says the same in plainer terms: fertilize lightly in spring and early summer, apply little or none in summer and put most of the nitrogen on after Labor Day.

Aeration is a September to October job (to October 20 in the east), a fall preemergence herbicide goes on from September 1 to October 15 for lawns with henbit or annual bluegrass, and fall is the ideal time to spot-spray broadleaf perennials such as dandelions. A last 0.5 pound feeding for newer lawns is October 15 to 30, and mowing continues until growth stops.

Fertilizer rules and soil tests

The Nebraska Department of Agriculture runs its fertilizer program as consumer protection under the Nebraska Commercial Fertilizer and Beneficial Substance Act, with licensing, registration and tonnage fees. I found no state limit on phosphorus in home lawn fertilizer on that page.

Nebraska Extension says soil type and pH strongly affect phosphorus and potassium needs, and advises leaving an unfertilized buffer strip around water bodies so phosphorus fertilizer does not reach the water. The lawn fertilizer calculator on this site turns the pounds of nitrogen in each calendar row into pounds of product for the bag you bought.