🌱 Seed Quantity Calculator

Seed Quantity Calculator User Guide

What It Does:
Calculate the exact number of seeds needed for your garden based on area, plant spacing, germination rates, and extra buffer for replacements.

How to Use:

🧮 Calculator Tab

1. Select Crop Type:
   • Choose from 12 common vegetables
   • Auto-fills spacing and germination data
   • Displays crop-specific planting information
2. Enter Garden Area:
   • Input total planting area in square feet
   • For the specific crop you’re planting
3. Plant Spacing:
   • Auto-filled when crop is selected
   • Or enter custom spacing in inches
   • Distance between plant centers
4. Germination Rate:
   • Auto-filled with typical rate for crop
   • Or enter custom percentage (1-100%)
   • Accounts for seeds that won’t sprout
5. Extra Seeds Buffer:
   • 10% – Standard buffer
   • 20% – Recommended (default)
   • 30% – Safe margin
   • 50% – Maximum coverage
6. Calculate:
   • Click “Calculate Seeds”
   • Results show:
     • Plants needed at maturity
     • Total seeds to plant
     • Seed packets required
     • Complete planting plan

📊 Seed Reference Tab

Quick reference guide for common vegetables with planting specifications.

Information for Each Crop:

• Recommended plant spacing
• Germination rate percentage
• Planting depth
• Days to germinate
• Average seeds per packet

Crops Included:

• Lettuce (6-8″ spacing, 80% germination)
• Tomatoes (24-36″ spacing, 75% germination)
• Peppers (18-24″ spacing, 70% germination)
• Bush Beans (4-6″ spacing, 90% germination)
• Carrots (2-3″ spacing, 65% germination)
• Radishes (2″ spacing, 85% germination)
• Cucumbers (12-24″ spacing, 80% germination)
• Corn (8-12″ spacing, 75% germination)

Calculation Formula:

Step 1: Calculate Plants Needed

textPlants = (√Area / Spacing in feet)²

Step 2: Account for Germination

textSeeds for Germination = Plants ÷ (Germination Rate ÷ 100)

Step 3: Add Buffer

textTotal Seeds = Seeds × (1 + Extra % ÷ 100)

Example: 100 sq ft of lettuce

• Spacing: 6 inches (0.5 ft)
• Plants needed: 400
• Germination: 80%
• Seeds: 400 ÷ 0.8 = 500
• With 20% extra: 600 seeds

Germination Rates:

High (85-90%):

• Radishes, Beans, Squash

Good (75-85%):

• Lettuce, Cucumbers, Spinach, Corn

Moderate (70-75%):

• Tomatoes, Peppers, Peas, Onions

Lower (65-70%):

• Carrots, Parsnips

Quick Tips:

✅ Always buy 20-30% extra – For poor germination and replacements
✅ Plant 2-3 seeds per spot – Thin to strongest seedling
✅ Check expiration dates – Fresh seeds = better germination
✅ Succession plant – Sow lettuce/radishes every 2 weeks
✅ Store properly – Cool, dry, sealed container extends viability

Pro Tip: Most seed packets contain way more seeds than you need for a small garden. For example, a single lettuce packet with 500 seeds can plant a 200 sq ft area! Share extras with friends or save for succession planting throughout the season.

Angelina Everly

With over 15 years of hands-on experience in controlled-environment agriculture, Angelina leads our lab audits. Her focus is on bridging the gap between high-end agricultural tech and the home grower, ensuring every recommendation is backed by real-world data and yield performance.