Redwood Seedling Collapse: Overwatering & Damping Off in Young Sequoias

Your coast redwood (Sequoia sempervirens) seedlings sprouted vigorously—then bent over and shriveled once the seed coat shed. The diagnosis: damping off from overwatering.

The Problem

• Watering every 3 days keeps the medium constantly wet—ideal for Pythium and Rhizoctonia fungi.
• Redwood seedlings need a wet-dry cycle. Their fine roots suffocate and rot in saturated soil.
• The "bent over" posture is the stem collapsing at the soil line—classic damping off.

Immediate Corrections

1. Water once a week only—let the top ½ inch dry between waterings.
2. Add air movement: Small fan on low, 24/7. Prevents fungal spore settlement and strengthens stems.
3. Apply milled sphagnum moss as a ⅛-inch top dressing after sowing. Suppresses surface fungi.
4. Cool temperatures: 50–60°F (10–16°C) slows fungal growth and mimics native coastal conditions.

Going Forward

• Use a sterile, soilless mix (peat/perlite/vermiculite).
• Sow seeds on surface; press lightly—don't bury.
• Bottom-water only; never let pots sit in water.
• Fertilize lightly (¼ strength) only after true needles appear.

Redwoods are unforgiving of soggy conditions but tough once established. Adjust the environment, and your next batch will stand tall.