Troubleshooting
Frosty Fern problems — and how to fix them
Frosty Fern (Selaginella kraussiana 'Frosty') is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Brown, crispy fronds
The classic symptom of low humidity or a dried-out root ball. Raise humidity (terrarium, cloche, humidifier) and never let the soil fully dry out.
Browning or bleaching in direct sun
Direct sunlight scorches the delicate foliage. Move to bright indirect light or partial shade.
Collapse and dieback after drying out
Has essentially no drought tolerance; one missed watering can cause fronds to droop, crisp and drop. Keep the mix evenly moist at all times.
Root rot and mushy stems
Caused by waterlogged, poorly drained soil. Use a draining pot and a moisture-retentive but airy mix; keep moist, not sodden.
Loss of white frosted tips
The bright tips are strongest in cooler conditions and good light; warm, dim spots fade them. Slightly cooler temps and bright indirect light keep the frosting vivid.
Yellowing leaves
Often from excess fertiliser or too much light. Feed only at half strength monthly in the growing season and shade from direct sun.
Prevent frosty fern problems before they start
Most frosty fern issues are care-mismatch, not bad luck. Dial in the basics:
Frosty Fern problems — FAQ
Why is my frosty fern brown, crispy fronds?
The classic symptom of low humidity or a dried-out root ball. Raise humidity (terrarium, cloche, humidifier) and never let the soil fully dry out.
Why is my frosty fern browning or bleaching in direct sun?
Direct sunlight scorches the delicate foliage. Move to bright indirect light or partial shade.
Why is my frosty fern collapse and dieback after drying out?
Has essentially no drought tolerance; one missed watering can cause fronds to droop, crisp and drop. Keep the mix evenly moist at all times.
Why is my frosty fern root rot and mushy stems?
Caused by waterlogged, poorly drained soil. Use a draining pot and a moisture-retentive but airy mix; keep moist, not sodden.
Why is my frosty fern loss of white frosted tips?
The bright tips are strongest in cooler conditions and good light; warm, dim spots fade them. Slightly cooler temps and bright indirect light keep the frosting vivid.
Why is my frosty fern yellowing leaves?
Often from excess fertiliser or too much light. Feed only at half strength monthly in the growing season and shade from direct sun.