Seeding Rate Calculation

Seeding Rate Calculator

Calculate the precise pounds of seed required per acre for optimal crop density.

Desired live plants per square foot.
Check your seed tag or crop guide.
Accounting for pests and soil conditions.

Results

Recommended Rate: 0 lbs/acre
Pure Live Seed (PLS): 0%
Total Seeds per Acre: 0

How to Use the Seeding Rate Calculator

Calculating the correct seeding rate is vital for maximizing yield and minimizing seed costs. Planting too much seed leads to excessive competition for nutrients and moisture, while planting too little leaves room for weed invasion and reduces total harvest potential.

The Mathematical Formula

Our calculator uses the standard agronomic formula for Pounds per Acre:

Seeding Rate (lbs/ac) = (Target Population/sq ft × 43,560) / (Seeds per lb × % Germination × % Purity × % Survival)

Understanding the Inputs

  • Target Population: The number of established plants you want per square foot. For example, Alfalfa is often 20-25 plants, while wheat might be 22-30.
  • Seeds per Pound: This varies significantly by crop variety. Small seeds like clover can have 250,000 per pound, while large soybean seeds may have only 2,500.
  • Pure Live Seed (PLS): This is the product of Germination and Purity. It tells you how much of the bag is actually viable seed of the desired crop.
  • Survival Rate: Not every viable seed becomes a plant. You must adjust for soil temperature, moisture, and potential bird or insect predation.

Practical Example

Suppose you are planting Winter Wheat:

  • Target Population: 25 plants/sq ft
  • Seeds per lb: 15,000
  • Germination: 90% (0.90)
  • Purity: 99% (0.99)
  • Expected Survival: 80% (0.80)

The calculation would be: (25 × 43,560) / (15,000 × 0.90 × 0.99 × 0.80) = 102.1 lbs/acre.

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 in all fields."); return; } var sqFtPerAcre = 43560; var totalSeedsNeeded = targetPop * sqFtPerAcre; // PLS = Purity * Germination var pls = germRate * purityRate; // Adjusted seeds per lb based on PLS and Survival var effectiveSeedsPerLb = seedsPerLb * pls * survivalRate; var lbsRequired = totalSeedsNeeded / effectiveSeedsPerLb; // Display results document.getElementById('lbsPerAcre').innerText = lbsRequired.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); document.getElementById('plsValue').innerText = (pls * 100).toFixed(1); document.getElementById('totalSeedsAcre').innerText = Math.round(totalSeedsNeeded / survivalRate).toLocaleString(); document.getElementById('seedingResult').style.display = 'block'; }

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