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Lawn Seed Calculator

Estimate the quantity of grass seed needed for new lawns or overseeding based on area, seed type, and application rate.

Application Type

New Lawn
Starting from bare soil
Overseeding
Filling in thin or bare spots

Lawn Area

Seed Type & Rate

Recommended: 8–10 lb/1,000 ft²

Bag Size (Optional)

$

How It Works

The calculator estimates the total grass seed needed by multiplying your lawn area by the recommended seeding rate for the selected grass type.

Basic Formula

Seed (lb) = Area (ft²) × Rate (lb/1,000 ft²) / 1,000

A waste factor is added to account for seed lost to wind, uneven spreading, birds, and slopes. The default 10% buffer is a good starting point for most lawns.

Adjusted Seed = Seed × (1 + Waste Factor%)

New Lawn vs Overseeding

New lawn seeding rates are higher because you are establishing grass from bare soil with no existing coverage. Overseeding rates are typically 40–60% of the new lawn rate since you are filling in gaps within an existing lawn.

Choosing the Right Seed

  • Cool-season grasses (Kentucky Bluegrass, Ryegrass, Fescues) thrive in northern climates with temperatures of 60–75°F
  • Warm-season grasses (Bermuda, Zoysia, Bahia, Buffalo, Centipede) prefer southern climates with temperatures of 80–95°F
  • Seed mixes combine multiple species for better disease resistance and adaptability

Seeding Rate Reference

Grass Type New Lawn (lb/1,000 ft²) Overseed (lb/1,000 ft²) Season
Kentucky Bluegrass2–31–2Cool
Perennial Ryegrass8–104–5Cool
Tall Fescue8–104–5Cool
Fine Fescue4–52–3Cool
Bermuda Grass1–20.5–1Warm
Zoysia Grass2–31–2Warm
Bahia Grass8–104–5Warm
Buffalo Grass2–31–2Warm
Centipede Grass1–20.5–1Warm

Tips for Successful Seeding

Preparation

  • Test your soil pH before seeding (ideal: 6.0–7.0 for most grasses)
  • Remove debris, rocks, and old vegetation
  • Loosen the top 2–3 inches of soil for new lawns
  • Mow existing lawn short and dethatch before overseeding

After Seeding

  • Keep soil consistently moist but not waterlogged
  • Water lightly 2–3 times daily until germination
  • Avoid foot traffic on newly seeded areas
  • Wait until grass reaches 3–4 inches before the first mow

Related Utils

Fertilizer Ratio Soil Volume Plant Spacing Watering Schedule

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