Seeding Rate Calculator

Calculate the precise pounds per acre required for your target plant population.

Target Plant Population (plants/ft²)

Seeds per Pound (qty/lb)

Germination Rate (%)

Seed Purity (%)

Expected Seedling Survival (%)

Results

Required Seeding Rate: 0 lbs/acre

Pure Live Seed (PLS): 0%

Total Seeds Needed per Acre: 0

function calculateSeedingRate() { var targetPop = parseFloat(document.getElementById('targetPop').value); var seedsPerLb = parseFloat(document.getElementById('seedsPerLb').value); var germRate = parseFloat(document.getElementById('germRate').value) / 100; var purityRate = parseFloat(document.getElementById('purityRate').value) / 100; var survivalRate = parseFloat(document.getElementById('survivalRate').value) / 100; if (isNaN(targetPop) || isNaN(seedsPerLb) || isNaN(germRate) || isNaN(purityRate) || isNaN(survivalRate) || seedsPerLb === 0) { alert("Please enter valid positive numbers for all fields."); return; } var sqFtPerAcre = 43560; var pls = germRate * purityRate; // Formula: (Target Pop * 43560) / (Seeds per lb * PLS * Survival) var ratePerAcre = (targetPop * sqFtPerAcre) / (seedsPerLb * pls * survivalRate); var totalSeedsNeeded = targetPop * sqFtPerAcre / (pls * survivalRate); document.getElementById('lbsPerAcre').innerText = ratePerAcre.toFixed(2); document.getElementById('plsValue').innerText = (pls * 100).toFixed(1); document.getElementById('totalSeeds').innerText = Math.round(totalSeedsNeeded).toLocaleString(); document.getElementById('resultsArea').style.display = 'block'; }

Understanding Seeding Rate Calculations

Achieving the optimal plant stand is the foundation of a successful harvest. If your seeding rate is too low, weeds will compete for resources and your yield potential will drop. If it is too high, you waste money on expensive seed and risk lodging or disease due to overcrowding. This Seeding Rate Calculator helps you determine exactly how many pounds of seed you need to buy and plant per acre to reach your target plant density.

The Components of the Calculation

Target Plant Population: The number of established plants you want per square foot. This varies by crop (e.g., Wheat often targets 25-35 plants/ft², while Alfalfa might target 20-25).
Pure Live Seed (PLS): This is a measure of the quality of the seed bag. It is calculated by multiplying the Germination percentage by the Purity percentage.
Expected Survival Rate: Not every seed that germinates will survive. Factors like soil temperature, planting depth, moisture, and pests affect survival. Usually, a 70% to 90% survival rate is used for calculation.
Seeds per Pound: The seed size significantly affects the weight needed. Small seeds (like canola) have many more seeds per pound than large seeds (like soybeans or peas).

Example Seeding Rate Calculation

Suppose you are planting Winter Wheat with the following parameters:

Target Population	30 plants/ft²
Seeds per Pound	14,000
Germination	95%
Purity	99%
Expected Survival	80%

Step 1: Calculate PLS = 0.95 × 0.99 = 0.9405 (94.05%).

Step 2: Calculate lbs/acre = (30 × 43,560) / (14,000 × 0.9405 × 0.80) = 124.08 lbs/acre.

Frequently Asked Questions

Why is Pure Live Seed (PLS) important?
Standardizing seed value based on PLS allows you to compare different seed lots. A cheaper bag of seed with low germination might actually be more expensive per pound of "growing" seed than a premium bag.

How do I determine my target population?
Check with your local agricultural extension or seed dealer. Variables like soil type, irrigation, and planting date (late-season planting often requires higher populations) influence the recommendation.

Does planting depth affect the seeding rate?
Indirectly, yes. If you plant deeper than recommended, your "Expected Seedling Survival" rate will decrease, meaning you need to increase the seeding rate to compensate for the higher mortality.