Autumn feeding for warm-season lawns
Taper nitrogen about six weeks before first frost, and apply potassium for winter hardiness as the lawn heads to dormancy.
- When
- Sep 1 – Oct 15 (northern hemisphere) · Mar 1 – Apr 15 (southern)
- Material
- autumn fertilizer (high potassium, low nitrogen)
- Rate
- 20–25 g/m² · about 4–5 lb per 1,000 sq ft
- For
- Warm-season lawns (Bermuda, Zoysia, St. Augustine)
- Needs
- spreader
- Rule
- wm-autumn-k · Walheim; Scotts; Turgeon
Taper nitrogen ~6 weeks before first frost (late N is frost-tender) and apply potassium for winter hardiness as the lawn heads to dormancy.
Why switch
Nitrogen pushes new leaf growth. On a warm-season lawn approaching dormancy, that tender late growth is the first thing frost kills, and it uses up reserves the grass needs to survive winter and green up next spring. Potassium does the opposite: it strengthens cell walls and roots and improves cold tolerance.
When
Stop high-nitrogen feeds about six weeks before the first expected frost. Apply the autumn feed from early September to mid-October in the northern hemisphere, March to mid-April in the southern.
What and how much
An autumn lawn fertilizer high in potassium and low in nitrogen, at 20–25 g/m², about 4–5 lb per 1,000 sq ft. Spread it evenly and water it in.
Alongside it
Keep mowing while the lawn grows, raise the cut a notch going into dormancy, and decide whether you want ryegrass for winter color or a Poa annua pre-emergent; you cannot have both.
Sources
- Lance Walheim — Lawn Care For Dummieswalheim
- Scotts — Lawnsscotts
- A.J. Turgeon — Turfgrass Managementturgeon