How to choose seed rate vs fertilizer rate
Seed quantity comes from the species blend on the bag (new-lawn rates are higher than overseed). Fertilizer quantity comes from your nitrogen target and the first N-P-K number. YardTally’s grass-seed defaults (3.5 lb/1,000 new, 1.75 lb/1,000 overseed) are mid cool-season planning figures—always override with the printed bag rate for your mix. Warm-season grasses and specialty blends can sit well outside that band.
Worked examples
- Seed: 5,000 sq ft × (3.5 lb ÷ 1,000) = 17.5 lb for a new cool-season lawn. The same area overseeded at 1.75 lb/1,000 needs 8.75 lb.
- Fertilizer: Target 1 lb N per 1,000 sq ft with a 25-0-5 product → product = 1 ÷ 0.25 = 4 lb per 1,000 sq ft. For 5,000 sq ft that is 20 lb of product (half of a 40 lb bag).
- Raised bed next to the lawn: an 8×4 ft bed 12 inches deep needs 32 cu ft (~1.2 cu yd) of mix—see the raised bed soil calculator.
Seasonal lawn calendar (planning)
| Season | Common tasks | YardTally tools |
|---|---|---|
| Early spring | Soil test, light cleanup, pre-emergent where appropriate | Fertilizer |
| Late summer / early fall | Best window for cool-season seed and overseed | Grass seed |
| Fall | Nitrogen feeding per local calendar; topdress thin spots | Topsoil |
| Anytime (beds) | Raised-bed fills next to the lawn | Raised bed soil |
Common mistakes
- Using new-lawn seed rates for overseeding (usually too much seed).
- Applying fertilizer by bag count without dividing by the nitrogen percentage.
- Skipping a soil test when pH or phosphorus limits growth more than nitrogen.
- Assuming one national calendar fits every USDA hardiness zone.
Guides: grass seed per sq ft, nitrogen per 1,000 sq ft, topsoil vs garden soil, 4×8 raised bed mix.