Your Result Explained: Exact Takeoff Breakdown
Establishing a 5,000-square-foot bare-ground lawn (such as a 100 ft by 50 ft suburban yard) with Turf-Type Tall Fescue (TTTF) requires higher seed weight per square foot than smaller-seeded grasses because Tall Fescue seeds are large and establish primarily as individual bunch-type plants with minimal rhizome spreading.
Using the Penn State and Purdue Extension new-lawn recommendation of 7.0 lbs per 1,000 sq ft, a 5,000 sq ft yard requires 35.00 net pounds of seed. Adding a 5% allowance for rotary spreader perimeter overlap brings your exact requirement to 36.75 lbs (16.67 kg). That equals 6 retail 7-lb bags (42 lbs total), or more economically, one 50-lb commercial nursery bag with ~13 lbs left over for spring spot repairs. Covering the 5,000 sq ft seedbed with a moisture-retaining 1/4-inch (0.25") layer of screened finished compost requires 109.38 cubic feet—equal to 4.05 cubic yards in bulk (or 110 bags at 1.0 cu ft).
For 36.75 lbs of seed, skip small 3-lb and 7-lb big-box bags and purchase a 50-lb bag of blue-tag certified 3-way Turf-Type Tall Fescue blend from a local agronomic supply house for $130 to $185, plus 4 cubic yards of bulk screened compost delivered.
Step-by-Step Math for a 100 ft × 50 ft New Tall Fescue Lawn
Computing Tall Fescue seed weight, bag counts, and 1/4-inch compost topdressing for a 5,000 sq ft new lawn with 5% spreader allowance.
- Net lawn area: 100 ft × 50 ft = 5,000 sq ft (5.0 thousand sq ft units).
- Net Tall Fescue seed (7.0 lbs/1,000 sq ft): 5.0 × 7.0 lbs = 35.00 lbs.
- Add 5% spreader overlap allowance: 35.00 lbs × 1.05 = 36.75 lbs (16.67 kg).
- Seed bag count (7 lb bags): 36.75 lbs ÷ 7 lbs/bag = 5.25 → 6 bags (or 1 × 50 lb bag).
- Net 0.25" topdressing volume: 5,000 sq ft × (0.25 ÷ 12) ft = 104.17 cu ft.
- Adjusted topdressing (+5%): 104.17 × 1.05 = 109.38 cu ft ÷ 27 = 4.05 cubic yards (110 bags at 1.0 cu ft).
Bottom Line: Purchase 36.75 lbs of uncoated Turf-Type Tall Fescue seed (6 × 7-lb bags or 1 × 50-lb bag) and 4.05 cubic yards of screened compost.
How This Scenario Is Calculated
We divide the 5,000 sq ft area by 1,000 to get 5.0 units, multiply by the 7.0 lbs/1,000 sq ft Turf-Type Tall Fescue new-lawn rate to reach 35.00 lbs, and multiply by 1.05 for 5% broadcaster overlap to get 36.75 lbs of pure seed.
For the 1/4-inch (0.25") compost topdressing, we multiply 5,000 sq ft by (0.25 ÷ 12) feet to obtain 104.17 net cubic feet, multiply by 1.05 to get 109.38 cubic feet, and divide by 27 cubic feet per cubic yard to arrive at 4.05 cubic yards (weighing ~4,456 lbs / 2.23 tons).
Seed (lbs) = (Area Sq Ft ÷ 1,000) × Rate per 1,000 Sq Ft × (1 + Waste%) Seed Bags = ⌈Seed (lbs) ÷ Bag Weight (lbs)⌉ Topdressing (yd³) = [Area × (0.25 ÷ 12) × (1 + Waste%)] ÷ 27 Project-Specific Tips & Common Mistakes
Buy a 50-Lb Commercial Bag Instead of Six 7-Lb Bags
Once a Tall Fescue project exceeds 30 lbs of seed, buying a single 50-lb commercial bag of NTEP-rated Turf-Type Tall Fescue saves 30% to 40% per pound and gives you 13 lbs of matching cultivar seed for touching up thin spots 4 weeks after germination.
Rent a Drum Compost Roller for 4 Cubic Yards of Topdressing
Spreading 4.05 cubic yards of compost evenly to 1/4 inch across 5,000 sq ft by hand with a shovel causes thick clumps that smother seed. Rent a 24-inch or 36-inch expanded-metal barrel compost spreader to sift a uniform 1/4-inch blanket over the seedbed.
Apply Starter Fertilizer High in Phosphorus (e.g., 18-24-12)
Tall Fescue germinates in 7 to 14 days and needs immediately available phosphorus at the soil surface to drive rapid primary root elongation before autumn frosts arrive.
Mistake Buying cheap "Kentucky 31" pasture fescue instead of Turf-Type Tall Fescue
Recommended Fix: KY-31 is a coarse, wide-bladed agricultural forage grass that forms clumpy pale-green stalks in home lawns. Always select a 3-way or 4-way blend of dwarf Turf-Type Tall Fescue (TTTF) cultivars.
Mistake Allowing the 5,000 sq ft seedbed to dry out between days 5 and 12
Recommended Fix: Once a Tall Fescue seed absorbs water and cracks its seed coat around day 5, a single afternoon of bone-dry baking sun will kill the emerging radicle root. Set multi-zone irrigation timers to run 3 light cycles daily.
Reference Coverage Table (Finished Organic Plant Compost / Humus)
Compare how coverage changes across common depths for Finished Organic Plant Compost / Humus (default planning density 1100 lbs/yd³):
| Depth | 1 Cubic Yard Covers | 1 Ton Covers | Yards / 100 sq ft | Tons / 100 sq ft | Bags (1 ft³) / 100 sq ft |
|---|---|---|---|---|---|
| 0.25 in Active | 1296 sq ft | 2356.4 sq ft | 0.08 yd³ | 0.04 tons | 3 bags |
| 0.5 in | 648 sq ft | 1178.2 sq ft | 0.15 yd³ | 0.08 tons | 5 bags |
| 1 in | 324 sq ft | 589.1 sq ft | 0.31 yd³ | 0.17 tons | 9 bags |
Reference Source: US Composting Council Test Methods for the Examination of Composting and Compost (TMECC).
Frequently Asked Questions
How many pounds of Tall Fescue seed do I need for 5,000 sq ft?
For a new bare-soil lawn of 5,000 sq ft, you need 35 lbs net (at 7 lbs per 1,000 sq ft), or 36.75 lbs when including a 5% allowance for spreader overlap. For overseeding an existing 5,000 sq ft lawn, you need half as much: 17.5 to 18.4 lbs.
How long does Tall Fescue take to germinate?
When soil temperatures are between 60°F and 75°F and the seedbed is kept consistently moist, Turf-Type Tall Fescue germinates in 7 to 14 days.
How much compost do I need to topdress 5,000 sq ft at 1/4 inch?
A 1/4-inch (0.25") topdressing layer across 5,000 sq ft with 5% waste requires 109.38 cubic feet, which is 4.05 cubic yards of bulk screened compost (or 110 bags at 1.0 cu ft each).
When is the best month to seed a 5,000 sq ft Tall Fescue lawn?
Late August through mid-September is the optimal window in the Transition Zone and northern US, giving seedlings 6 to 8 weeks of cool sunny growing weather before winter dormancy.
Should I roll the soil after seeding 5,000 sq ft?
Yes. Lightly rolling the bare soil with an empty or quarter-filled lawn roller after raking in the seed presses the large Tall Fescue seeds against moist soil capillaries, speeding germination by 2 to 3 days.