Seed Planting Depth Guide: How Deep to Sow for Strong Germination

Planting seeds at the right depth can mean the difference between:

• Strong, uniform germination 🌱
• Or seeds that dry out, rot, or exhaust themselves before reaching light

The golden rule is simple:

Plant seeds at a depth of 2 to 3 times their thickness.

Large seeds go deeper. Tiny seeds stay close to the surface.

Below is a practical depth guide for common garden crops — so you can sow confidently and get stronger results.

🌤 Barely Covered (About 1/4 Inch or Surface-Sown)

These seeds are tiny and often need light to germinate. Do not bury deeply.

Basil

• Press lightly into soil surface
• Do not bury deeply
• Keep evenly moist

Lettuce

• Light-dependent germination
• Sprinkle on surface and tamp gently
• Thin seedlings once established

Celery

• Very slow to sprout (15–20 days)
• Keep consistently moist
• Benefits from a humidity dome during germination

🌱 1/2 Inch Deep

Small but sturdy seeds that need a light soil covering.

Carrot

• Mix seeds with sand for even spacing
• Germinates in 10–15 days
• Keep surface consistently moist

Parsley

• Very slow (3–4 weeks)
• Do not give up too soon

Radish

• Fastest garden crop
• Sprouts in 4–5 days
• Ready to harvest in about 25 days

🌿 3/4 Inch Deep

Medium seeds that need warmth and steady moisture.

Tomato

• Start indoors 6–8 weeks before last frost
• Needs at least 68°F (20°C) to germinate
• Sprouts in 7–10 days

Pepper

• Requires consistent warmth
• Do not let soil drop below 65°F (18°C)
• Germinates in 10–15 days

Eggplant

• Slowest of the nightshades
• 12–18 days to sprout
• Ideal temperature around 77°F (25°C)