Fertiliser burn
Too much fertiliser, or feed applied to dry compost, raises the salt level around the roots so they lose water instead of taking it up. Leaf tips and margins brown, and a white crust can form on the compost and pot rim.
Soil & nutrients
What it looks like
The damage shows on the leaves but starts at the roots.
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Brown tips Leaf tips turn brown and crisp, often with a yellow band behind. -
Scorched margins The browning spreads along the leaf edges. -
White crust A pale salt crust forms on the compost surface and the pot rim. -
Sudden wilt Seedlings collapse after a strong feed.
How to confirm it
Look at the feeding and the pot.
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Recent feeding
Browning a few days after a feed, especially a strong one or on dry compost.
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Salt crust
A white residue on the compost or rim.
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All leaves affected
Unlike scorch, the tips brown regardless of which way they face.
What to do
Wash the salts out, then feed less.
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Flush the pot
Run clean water through the compost, three to four times the pot's volume, and let it drain.
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Repot if severe
Replace crusted compost with fresh, and trim dead roots.
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Pause feeding
Wait until new growth before feeding again, at half strength.
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Trim tips
Cut off brown tips following the leaf shape if they bother you.
Prevent it next time
- Feed only moist compost, never dry.
- Use half the recommended strength for houseplants and seedlings.
- Stop feeding houseplants in winter.
- Flush pots through every couple of months.
What not to do
Do not feed a wilting plant; if the roots are burnt, more feed completes the job.
Sources
- Leaf damage on houseplants, Royal Horticultural Society
- Fertilisers, Royal Horticultural Society