Air plants (Tillandsia) take in water through their leaves, so the water you use touches the part of the plant that does the absorbing. That makes water quality worth a few minutes of thought.

It is also easy to blame the water for problems it did not cause. Brown tips are the classic example. The extension sources we checked connect brown tips to too little water, not to chlorine. This guide covers which water to use, what each source says about tap, hard, softened and distilled water, and what to check before you change anything.

How air plants drink

NC State Extension explains that air plant roots are holdfasts that cannot absorb enough water to supply the leaves. Instead, silvery grey, shield-shaped scales on the leaves absorb water and nutrients. The RHS calls these water-absorbent cells trichomes, and says they are the plant’s main way of taking moisture from rain or fog.

That is why hard water matters more here than for a potted plant. Anything that coats the scales gets between the plant and its water.

Which water to use

WaterWhat the sources say
RainwaterThe RHS recommends immersing plants in rainwater. Vermont Extension lists it first. University of Maryland Extension notes rainwater has no added chemicals.
Bottled waterVermont Extension lists it as an option.
Tap waterVermont Extension says to let it stand overnight so chlorine evaporates. The RHS says to avoid tap water, especially in hard-water areas.
Hard tap waterThe RHS says dissolved sodium bicarbonate can precipitate on the trichomes and block them, preventing the plant from absorbing moisture and nutrients.
Softened waterVermont Extension says to avoid it because the salt is harmful to air plants. Maryland says softened water carries more dissolved minerals and should be avoided for houseplants.
Filtered or distilled waterVermont Extension says to avoid it because it may contain insufficient nutrients. Virginia Cooperative Extension says distilled water lacks dissolved nutrients and prolonged use can cause deficiencies.

The practical order is simple. Use rainwater if you can collect it. Vermont Extension’s stood-overnight tap water is the fallback, but the RHS warning means it suits areas without hard water. Avoid water from a household softener.

What we can and cannot say about chlorine

The chlorine question deserves a straight answer.

  • A Cornell Cooperative Extension Master Gardener article says air plants can be sensitive to chlorine and fluorine.
  • Vermont Extension advises letting tap water sit overnight so the chlorine evaporates.
  • Virginia Cooperative Extension says some houseplants are sensitive to chloramine, a different disinfectant in some tap water. It does not say that standing removes it.

None of these sources describe what chlorine damage looks like on an air plant. None give a level that causes harm. So we cannot tell you that brown tips, or any other symptom, come from chlorine. Standing tap water overnight is low-effort advice from Vermont Extension, and rainwater sidesteps the question.

Check watering before blaming the water

Two extension sources describe the same picture for a thirsty air plant:

  • Illinois Extension: dry plants curl or roll, look dull in colour, and tips may brown.
  • Cornell Cooperative Extension: slightly rolled or curled leaves mean it is time to water, and brown leaf tips are a sign the plant is not getting enough water.

So if your plant has brown tips, start with how often and how thoroughly you water. NC State says that although air plants cope with drought, they need regular watering, at least once a week, to thrive.

What you seeMost likely cause in the sourcesWhat to check
Curled or rolled leaves, dull colour, brown tipsToo little water (Illinois, Cornell)How often you water, and whether you soak or only mist
Dull, coated leaves in a hard-water areaMineral deposits on the scales (RHS)Your water source
Soft or rotting base or centreWater trapped in the plant (Vermont, RHS)How the plant drains and dries after watering

Brown tips do not turn green again. Judge any change by new growth.

How to water

The sources describe three methods. Pick one that fits your room and stick to drying the plant afterwards.

  1. Soaking. Vermont Extension says to immerse the plant in room-temperature water for 30 to 60 minutes once a week. Illinois suggests about 30 minutes in lukewarm water. The RHS recommends immersion in rainwater two to three times a week from spring to autumn.
  2. Rinsing. Illinois says to hold the plant under lukewarm water for a few seconds, one to two times a week. Cornell suggests rinsing twice a week. NC State notes many growers plunge the plant into a bucket or put it under the shower.
  3. Misting. Illinois says to mist every other day until water runs off. The RHS says misting can help prevent dehydration in warm weather but is not enough on its own and should not replace immersion.

The RHS adds that plants may need water more often in warm, dry rooms and less often in cool, humid ones.

Drying matters as much as the water

The RHS says allowing plants to dry between waterings is very important. Tillandsia will not tolerate being kept continuously wet. After watering:

  • Drain the crown. Vermont Extension says to drain plants on their side or upside down for an hour or two, because water collecting in crevices can cause rot. The RHS suggests mounting plants angled downwards, or shaking them gently.
  • Give them air. The RHS says air plants evolved with strong air movement and need a well-ventilated position. Illinois says good air circulation lets the plant dry and prevents foliage disease.
  • Wait before closing a terrarium. Cornell says to let plants dry for at least 4 hours before returning them to a terrarium. Illinois says several hours.
  • Skip watering in the cold. The RHS says not to water when temperatures drop to 12 °C (54 °F), because plants stay wet too long.

The RHS says air plants do best above 12 °C (54 °F) and tolerate up to 30 °C (86 °F) if humidity is high. Vermont Extension gives a range of 10–32 °C (50–90 °F).

Feeding and water

Water quality and feeding overlap, because rainwater and distilled water carry few nutrients. The sources take a light approach. Vermont Extension says fertilizer is not needed, but if you use it, choose one made for air plants and follow the label. Illinois suggests a balanced fertilizer at quarter strength once a month. The RHS suggests an occasional overnight summer soak in water with orchid fertilizer added.

A simple routine

  1. Collect rainwater, or let tap water stand overnight. Never use softened water.
  2. Soak or rinse at least weekly, more often in warm, dry rooms.
  3. Shake out the crown and dry the plant upside down or on its side.
  4. Keep it in bright, diffused light with moving air.
  5. If tips brown and leaves curl, water more thoroughly or more often before changing the water source.

For species differences, see our guide to air plant types. For tap water across houseplants, see the tap water guide.

References