Seedling Stage
Part of the free Stevie Weedseed grow guide. No paywall, no account, written by a working grower.
What to Expect
The seedling stage begins when the plant breaks through the soil. It lasts about 10-14 days. The plant develops cotyledons (round baby leaves), then its first true cannabis leaves, and begins building roots.
Seedlings are fragile but grow quickly when conditions are right.
Seedlings are fragile but grow quickly when conditions are right.
Lighting
Schedule: 18 hours light, 6 hours dark.
Distance: LED at 24-36 inches above seedlings.
PPFD target: 100-300 μmol/m²/s.
DLI target: 12-16 mol/m²/day.
Signs light is too strong: leaves curling up, bleaching, seedlings staying very short.
Signs light is too weak: tall thin stretching stems.
Use the DLI Calculator →
Distance: LED at 24-36 inches above seedlings.
PPFD target: 100-300 μmol/m²/s.
DLI target: 12-16 mol/m²/day.
Signs light is too strong: leaves curling up, bleaching, seedlings staying very short.
Signs light is too weak: tall thin stretching stems.
Use the DLI Calculator →
Watering
Overwatering is the #1 seedling killer. Their root systems are tiny.
Use a spray bottle. Water a small circle around the plant. Allow the soil to become slightly dry between watering. The goal is damp, never wet.
If the seedling droops and the soil is wet, you are overwatering. Stop watering and let it dry out.
Use a spray bottle. Water a small circle around the plant. Allow the soil to become slightly dry between watering. The goal is damp, never wet.
If the seedling droops and the soil is wet, you are overwatering. Stop watering and let it dry out.
Nutrients
Most quality soils contain enough nutrients for the first 2-3 weeks. Do NOT feed seedlings.
Adding nutrients too early causes nutrient burn (brown, crispy leaf tips), stunted growth, and dark green clawing leaves.
Start feeding only when the plant has 3-4 sets of true leaves, and start at 1/4 strength.
Adding nutrients too early causes nutrient burn (brown, crispy leaf tips), stunted growth, and dark green clawing leaves.
Start feeding only when the plant has 3-4 sets of true leaves, and start at 1/4 strength.