Gadenin日本語Get the appBrown tips are usually salts, not dry air
Every areca palm in a living room ends up with some brown on the tips, and almost everyone blames the humidity first. Humidity is a real factor, but it is rarely the main one. A palm frond is the last stop in the plant's transpiration stream, so whatever is dissolved in the water you pour on the pot is carried out to the very ends of the leaflets and left there when the water evaporates. Fluoride, boron, sodium from softened water and leftover fertilizer all concentrate at that point.
The pattern tells you which problem you have. A salt or fluoride tip is dry, papery and tan to dark brown, with a thin yellow band between the dead part and the healthy green, and it stops there. Damage that creeps inward as a soft, dark, spreading patch is a root problem, and damage that appears as fine pale stippling across the whole leaflet before it browns is spider mite.
| What you see | Most likely cause | First move |
|---|---|---|
| Dry tan tips with a narrow yellow halo | Fluoride, sodium or fertilizer salts | Change water source and leach the pot |
| White or yellow crust on the compost surface | Salt accumulation from feeding | Scrape the crust off and flush thoroughly |
| Whole lower fronds yellowing, compost wet | Roots suffocating in wet compost | Stop watering and check the root ball |
| Fine pale speckling before any browning | Spider mite in dry air | Inspect the leaflet undersides with a lens |
| Tips brown only on the side facing a radiator | Hot dry airflow | Move the pot out of the draft |
A brown tip never turns green again. Judge whether the change worked by watching the fronds that open after you made it, not by staring at the damaged ones.
Change what comes out of the can
Switching water source is the cheapest test available and it fixes most areca tip burn. Give the plant a different water for two or three months and compare the new growth against the old fronds.
- Use rainwater or distilled water Both carry essentially no fluoride and almost no dissolved salt. Two gallons (eight liters) collected off a downpipe will keep a large areca going for a month, and it is the single most reliable change you can make.
- Never use softened water A domestic water softener swaps calcium for sodium, and sodium damages palm foliage faster than the hardness it replaced. If the house is softened, fill your can from an outside tap that bypasses the unit.
- Standing water only removes chlorine Leaving tap water out overnight lets chlorine gas off, which is worth doing, but fluoride and sodium are dissolved salts and stay exactly where they were. Do not expect standing water alone to stop tip burn.
- Water at room temperature Cold water straight from the tap chills the root ball and slows uptake for a day or two. Fill the can, leave it in the room overnight, and you solve the temperature and the chlorine at the same time.
How often to water
An areca has a dense, fibrous root system that fills the pot and wants to be evenly moist, never soaked and never bone dry. It is less tolerant of drought than most houseplants and far less tolerant of standing water. Go by the weight of the pot rather than by a fixed day count, and push a finger two inches (5 cm) into the compost before every watering.
| Season | Room temperature | Interval | Method |
|---|---|---|---|
| Spring | 64 to 75F (18 to 24C) | Every five to seven days | Water until it runs from the base, then empty the saucer |
| Summer | Above 75F (24C) | Every three to five days | Morning, generously, plus one full flush in the season |
| Autumn | 59 to 70F (15 to 21C) | Every seven to twelve days | Stretch the interval as light levels fall |
| Winter | 54 to 64F (12 to 18C) | Every two to three weeks | A mild morning drink. Reduce frequency, not the amount |
A palm in a dim corner uses a fraction of the water of the same plant at a bright window. If you move it somewhere darker, lengthen the interval that same day rather than waiting for the leaves to complain.
Flush the pot every few months
Each watering leaves a small residue behind, so after a year or two the compost holds far more salt than any single watering delivered. Leaching washes it back out, and on a fed plant it is worth doing three or four times a year.
- Move it where water can escape A sink, a shower tray or outside on a mild day. Flushing into a saucer defeats the purpose, because the salts dissolve, sit under the pot and get drawn straight back up as the compost dries.
- Run four pot volumes through slowly For a ten inch (25 cm) pot that is about three gallons (twelve liters). Pour slowly enough that the water soaks through the root ball instead of channeling down the gap at the side of the pot.
- Scrape off any crust White or yellowish crystals on the compost surface or around the rim are concentrated salt. Take off the top half inch (1 cm), discard it, and top up with fresh compost after the pot has drained.
- Let it drain for an hour The compost will be fully saturated afterwards, so the next watering is further away than usual. Do not put it back on a full saucer while it is still dripping.
Do not feed in the same month you flush. Feeding immediately after leaching puts the salt concentration straight back where it was.
Feeding, and why less is more
Areca palms are light feeders and the most common cause of severe tip burn on an otherwise well kept plant is simply too much fertilizer. Use a balanced liquid feed at half the strength printed on the bottle, once a month while the plant is putting out new fronds, and stop entirely once growth slows for the winter.
Never feed a dry root ball. Water first, wait an hour, then apply the feed. Fertilizer drawn into dry compost concentrates against the roots and scorches them, and the damage shows up on the foliage weeks later when you have forgotten what caused it.
What to write down
Tip burn is slow, so memory is a poor guide. Keep a short note of the date you changed water source, the date of each flush, the date and strength of each feed, and roughly how many new fronds have opened since. Six months later that record tells you whether the fix worked, because you can count clean new fronds against damaged old ones instead of guessing.
It is also worth noting which side of the pot faces the window and when you last turned it. Fronds lean toward light within a couple of weeks, and a quarter turn at every watering keeps the crown symmetrical without you ever having to think about it.