Tall fescue is a resilient, cool-season bunchgrass valued for its deep root system, providing durability in turf applications and consistent forage production. The quantity of seed required per acre is not a fixed number, but a flexible metric dependent on the application’s specific goal. This hinges on whether the area is being established anew or simply renovated, as well as the desired density of the final stand. Calculating the necessary seed volume requires understanding these variables.
Seeding Rates Based on Application Type
The rate of tall fescue seed needed per acre varies significantly between establishing a new lawn and renovating an existing stand, reflecting the difference in intended seed density. For new turf establishment, the goal is to create a dense, uniform stand quickly, requiring a high seeding rate applied to bare soil. This typically translates to a range of 305 to 350 pounds of turf-type tall fescue seed per acre. This high rate ensures the numerous seeds per square foot develop into a thick, competitive lawn surface.
When renovating or overseeding an existing lawn, the requirement decreases because the seed is meant to fill in thin areas rather than cover the entire ground. Overseeding rates for turf-type fescue generally fall between 175 and 350 pounds per acre. The lower end of this range is suitable for moderately thin lawns, while the higher end is reserved for areas with significant bare patches requiring intensive application.
In contrast, tall fescue used for pasture or forage production requires a much lighter application rate, as the goal is biomass production rather than turf density. Forage varieties are seeded at a rate of 15 to 25 pounds per acre. This lower rate prevents excessive competition among seedlings, allowing each plant to grow more robustly. Drilled seedings often use the lower end of the range compared to broadcasting, which requires a slightly higher rate.
Calculating Seed Requirement Adjustments
Standard seeding rates assume high-quality seed, but the actual weight of seed purchased must be adjusted using the Pure Live Seed (PLS) calculation. PLS is the percentage of the purchased seed that is both the desired species and capable of germination. It is determined by multiplying the seed’s Purity Percentage by its Germination Rate. Seed tags provide these percentages, which are required by law to represent the seed lot’s quality.
For example, if a seed lot has 95% Purity and 85% Germination Rate, the PLS percentage is 80.75% (0.95 multiplied by 0.85). This means only 80.75% of the bulk seed weight is expected to grow into a viable plant. To meet a target application rate of 300 pounds of PLS per acre, the total bulk seed weight purchased must be increased to compensate for inert material and non-viable seeds.
To find the bulk seed requirement, divide the target PLS rate by the calculated PLS percentage. Using the previous example, 300 pounds divided by 0.8075 requires purchasing approximately 371.5 pounds of bulk seed. Accounting for PLS ensures the proper number of live seeds are spread, which is necessary to achieve the desired stand density.
Essential Steps for Ground Preparation
Successful establishment of tall fescue begins with thorough preparation of the planting site. Soil testing is the first action to determine existing pH and nutrient levels, which guides the need for soil amendments. Tall fescue performs best in a soil pH range of 5.5 to 7.5. Any required lime or sulfur should be incorporated into the soil based on the test results.
Controlling existing vegetation is equally important, as weeds quickly outcompete new fescue seedlings for light, water, and nutrients. Non-selective herbicides are often used to eliminate competing growth, requiring a waiting period before seeding to prevent damage to the new grass. Afterward, the dead vegetation and soil should be lightly tilled one to two inches deep to create a loose, fine seedbed.
The final preparation steps focus on ensuring proper grade and maximizing seed-to-soil contact for germination. The tilled area should be raked smooth to remove debris and establish a uniform surface that allows for adequate drainage. After the seed is spread, it must be worked into the soil, covered by no more than a quarter-inch of soil, and lightly rolled. This process firms the seedbed, retaining moisture and encouraging rapid establishment.