PlantIf the roots and drainage are sound, flush the pot with 2–3 times its volume of clean water, then feed nothing until healthy new leaves unfold.
What “burn” really is
Fertilizers are salts. Dissolved at the right strength (an electrical conductivity of roughly 0.8–1.5 mS/cm for most foliage houseplants), they feed the plant. Too concentrated, they raise the salt level of the soil solution until water moves out of the root cells instead of in, which is osmotic stress. The finest root tips die first, and the plant shows drought symptoms while sitting in wet mix.
On the leaves, damage appears where transpired water ends its journey: the tips and margins. Salts concentrate there as water evaporates, and the tissue browns from the edge inward, often with a yellow band between the dead and healthy tissue. A single double-strength feed rarely does this to a healthy plant. Repeated overdoses, or salts building up over months, do.
Symptoms and look-alikes
Typical signs are sudden wilting or leaf drop in moist mix within a few days of feeding; crisp brown tips and margins on several leaves at once; a white or yellowish crust on the mix surface or the rim of a terracotta pot; and roots with brown, dead tips that slide off when pulled gently. Growth stalls because a damaged root system cannot take up water or nutrients.
Several problems look similar. Dracaena, spider plant (Chlorophytum comosum) and peace lily are sensitive to fluoride and boron in tap water and get tip burn even without overfeeding; underwatering and cold draughts also brown leaf edges. The clues that point to fertilizer are timing (damage soon after feeding), a salt crust, and many leaves affected at once rather than one or two old ones.
How pots end up oversalted
Most cases trace back to routine habits rather than one big mistake. Check your own routine against this list before you change anything else.
- Measuring a concentrate with the wrong spoon, or mixing a dose meant for 4 L into a 1 L can.
- Feeding a bone-dry root ball, which puts concentrated solution straight onto stressed root tips. Water first, feed next time.
- Stacking sources: a mix that “feeds for up to 6 months”, plus controlled-release granules, plus liquid feed.
- Feeding at full rate through winter, when low light slows uptake and salts accumulate.
- Only ever giving small sips that never drain, so salts are never flushed out.
- Using softened water, which swaps calcium for sodium.
Leach the pot or repot it
If drainage works and most roots are still firm and pale, leach. Take the plant to a sink or bath and slowly pour room-temperature water through the mix, 2–3 times the pot’s volume (2–3 L for a 1 L pot), letting it run freely out of the holes. Scrape off any visible surface granules and the top 1 cm of crusted mix first. Let it drain completely, then return it to bright indirect light and do not water again until the top 2–5 cm is dry.
If the roots are mostly brown and mushy, or the mix is compacted and sour-smelling, leaching will only drown what is left. Instead, repot into fresh, unfertilized mix in a pot no larger than the healthy root mass, trimming dead roots with clean scissors. Do not add vinegar, baking soda or other home “neutralizers”; they add more salts or shift pH without removing anything.
Restart feeding carefully
Brown margins will not recover. Trim them if you like, following the leaf’s natural outline and leaving a thin line of brown so you do not cut into live tissue. Wait for 2–3 healthy new leaves, typically 4–6 weeks in the growing season, before feeding again.
Then resume at half the label rate every 2–4 weeks from spring to late summer, and pause in winter unless the plant is under grow lights. Water so that 10–20% runs out of the bottom each time. That steady runoff is the best way to stop salts from building up again.
