Guide · Feeding
The fall nitrogen program for cool-season lawns
If you only fertilize a fescue or bluegrass lawn once a year, make it fall. Three times is better.
Why fall beats spring
In fall, cool-season grass puts its energy into roots, new shoots (tillers) and stored sugars rather than leaf. Nitrogen now builds density that lasts into next summer. Heavy spring nitrogen does the opposite: a flush of top growth, more mowing, thinner roots going into the heat, and more brown patch. Many university extension programs put most of the year's nitrogen in fall for exactly this reason.
The three feeds
| Feed | When | Nitrogen (lb per 1,000 sq ft) |
|---|---|---|
| 1. Recovery | Around Labor Day, as the heat breaks | About 1 |
| 2. Build | 4–6 weeks later (early to mid October in most places) | About 1 |
| 3. Late fall | Around your last mow, before the ground freezes | About 1 |
Start earlier in the northern tier and mountains, later in the transition zone. If you overseeded, the starter fertilizer at seeding counts as feed 1; do feed 2 about 4–6 weeks later.
Yearly totals: tall fescue and bluegrass do well on 2–4 lb of nitrogen per 1,000 sq ft a year; fine fescue wants much less (1–2 lb) and should get only one light fall feed.
The bag math
The first number on the bag is the percent nitrogen. To put down 1 lb of nitrogen per 1,000 sq ft:
Pounds of product per 1,000 sq ft = 1 ÷ (first number ÷ 100)
A 32-0-4 bag: 1 ÷ 0.32 = about 3.1 lb of product per 1,000 sq ft.
A 24-0-10 bag: 1 ÷ 0.24 = about 4.2 lb per 1,000 sq ft.
For a 5,000 sq ft lawn, multiply by 5: 15.6 lb and 21 lb.
A "5,000 sq ft" bag often supplies a bit less than 1 lb of nitrogen per 1,000 sq ft at the printed setting. That's fine for feeds 1 and 2; just don't go over about 1 lb per feed.
Quick-release or slow-release?
- Early fall: either works. A blend with some slow-release nitrogen evens out the response.
- Late fall: quick-release (urea, ammonium sulfate) is the better pick. Slow-release and organic products depend on warm soil and microbes, which slow way down in November.
Water it in, keep it off the pavement
Water granular fertilizer in with about ¼ inch, and blow any granules off driveways, sidewalks and streets back onto the lawn. Anything on the pavement ends up in the storm drain.
Local cutoff dates
Some states limit when you can fertilize. For example, New Jersey and Maryland prohibit lawn fertilizer from mid-November to March 1, and New York from December 1 to April 1. Many states also restrict phosphorus on established lawns (look for a 0 as the middle number). Check your state and county before the late-fall feed.
Warm-season lawn (bermuda, zoysia, St. Augustine, centipede, bahia)? This program isn't for you: stop nitrogen about 6 weeks before first frost. See "Winterizer" fertilizer.
The Lawn Obsessed USA app times each of these feeds for your ZIP and grass, and its dose calculator does the bag math for your exact square footage.