Fertilizer burn
Brown, scorched leaf edges and damaged roots caused by too much fertilizer or a build-up of salts in the soil.
Also known as: Salt burn, Overfertilizing
Symptoms and identification
Leaf tips and edges turn brown and crispy, sometimes with a yellow band behind. A white crust forms on the soil surface or pot rim, and plants wilt or stop growing even in moist soil.
Causes
Applying fertilizer too often, at too high a concentration, onto dry soil, or using fresh manure. Hard water and poor drainage add to the salt build-up in containers.
Organic treatment
Scrape off any crust and flush the pot by running slowly through it about four times the pot's volume of water. Trim burned leaves and do not feed again for a month.
Prevention
Feed at half the label strength and only during active growth. Always water before applying fertilizer, and flush pots with plenty of water every few months.
Chemical treatment (use with care)
Not needed.