Plant records · Medium light
Spider plant: brown tips, and why this one really is the water
Chlorophytum comosum is the plant most often recommended for beginners and the one most often described as having brown tips from low humidity. For this species that advice is wrong. Spider plant tip burn is caused by fluoride and boron in tap water, and it is solved by changing what you water with, not by misting.
Chlorophytum comosum · Asparagaceae
| Botanical name | Chlorophytum comosumAsparagaceae |
|---|---|
| Light | 400-1,500 lxMedium light |
| Humidity | 40-60% |
| Watering | Every 9 days |
| Drainage | General-purpose mix with extra perlite: 65% compost, 20% perlite, 15% bark. The plant's tuberous roots store water, so the mix should not be kept continuously moist. |
| Mature height | 45 cm |
| Growth rate | Fast: produces a full flush of new leaves each spring and sends out runners with plantlets from spring to autumn on a mature plant. |
| Propagation | Detach plantlets from the runners and pot them up while still attached to the parent, or cut them off once they have small roots. They root in soil or water within two weeks. |
| Pet safety | safeNon-toxic to cats and dogs according to the ASPCA. One of the safest common houseplants for households with pets, and cats are often attracted to the arching leaves. |
presentationWhat you are seeing
- Brown, dead tissue at the tips of many or most leaves, with a sharp line between brown and green, on a plant that is otherwise healthy and growing.
- A plant with pale, washed-out leaves with faint or missing stripes, on a cultivar that should be strongly variegated.
- Brown tips plus a general lack of new plantlets on a mature plant that used to produce them constantly.
aetiologyWhy it happens
- Spider plant tip burn is a fluoride and boron toxicity symptom. Chlorophytum is unusually sensitive to both, and both are added to many municipal water supplies — fluoride deliberately, boron as a trace contaminant. The plant takes them up and deposits them at the leaf tip, where they accumulate to toxic concentration and kill the tissue.
- Pale, washed-out leaves mean insufficient light. The variegation in this species is chlorophyll-deficient tissue; in shade the plant produces leaves with more green and less white, and the stripes fade.
- Loss of plantlet production on a mature plant is usually root congestion plus exhausted mix, or simply low light. Plantlets are produced when the plant has surplus energy.
managementWhat to do
- Change the water. Rainwater, distilled water, or filtered water with a fluoride-removing filter all eliminate tip burn. If you must use tap water, let it stand overnight — this removes chlorine but not fluoride, so it helps less than is often claimed.
- Do not over-fertilise. Excess fertiliser salts accumulate at the leaf tip in the same way fluoride does. Feed at half strength every fourth watering in summer only, and not at all from October to February.
- Flush the pot every three months with rainwater to clear accumulated salts.
- For faded variegation: move to 400-1,500 lx. An east window 0.5-1 m back is ideal. Direct midday sun will scorch the leaves, so a south window needs a sheer.
- Trim the brown tips with scissors, cutting at a slight angle following the leaf's natural shape. Trimming does not stop new tip burn; only changing the water does.
The fluoride problem, in detail
Many municipal water supplies are fluoridated at 0.7-1.0 mg/l. Chlorophytum comosum is damaged by fluoride at concentrations well below that. The plant takes it up with water and transports it to the leaf tip, where there is no mechanism to excrete it. Over months the concentration at the tip reaches toxic levels and the tissue dies.
The same phenomenon occurs with boron, present as a trace contaminant in some water supplies, and with the soluble salts in fertiliser. This is why the problem gets worse over time in a plant that has been in the same pot for two years.
The most practical fix in a flat without rainwater access is a filter jug with an activated carbon and ion exchange cartridge, or buying distilled water for the plant — it needs roughly 200 ml a week, which is a trivial amount.
- Rainwater: best, free if you have outdoor space
- Distilled or deionised: ideal, cheap in small volumes
- Carbon + ion exchange filter jug: good, removes most fluoride
- Tap water left overnight: removes chlorine only, not fluoride
- Fertiliser: half strength, summer only, and flush quarterly
Why the plantlets are worth keeping
A mature spider plant on a runner does the propagation for you. Each plantlet is a small plant with its own leaf rosette, and by the time it is 5 cm across it usually has small root primordia at its base.
You can either leave the plantlet attached until it forms roots and then cut it off, or pin it into a small pot of mix while still attached to the parent and cut the runner after three weeks. The second method gives a much higher success rate and a plant that establishes without any transplant check.
Pot size and the tuberous roots
Spider plant roots are thick, white and tuberous, and they can crack a plastic pot from the inside. The plant does best when slightly root-bound, which is also what triggers plantlet production. Do not move it into a large pot.
When you do repot, go up one size only and use fresh mix. If the tuberous roots have filled the pot completely, divide the plant rather than potting it up — three divisions from one congested plant will all grow better than a single plant in a larger pot.
Sheets that reference this plant
| Yellowing leaves | Yellowing is the single most common houseplant complaint and it covers at least six unrelated problems. The fastest way to separate them is not to… |
|---|---|
| Crispy brown tips | Brown leaf tips look identical whatever caused them, which is why so many people treat the wrong thing for years. In practice there are four causes… |
Troubleshooting
Are the brown tips caused by low humidity?
Is spider plant safe if my cat eats it?
My plant used to make lots of babies and now makes none. Why?
CaveatCare information only. Listed as non-toxic to cats and dogs; consult a veterinarian with any concern about ingestion rather than relying on this page.
Published2026-08-28 ·