Plant mister: what it does, and what it does not do

A plant mister moistens foliage, mosses and the surface of the substrate without flooding the soil. It is useful for a terrarium, for mosses or to rinse dust off tropical leaves. It does not replace watering, and it only raises air humidity for a short time. This guide explains when to mist, with what water, and how to get humidity that lasts.

What a plant mister is for

A mister sends out a fine mist. The water settles in small droplets and does not dig into the substrate. Its uses are simple:

• Rehydrate mosses and the surface of the substrate, in a terrarium or in a pot.
• Rinse dust off the leaves of tropical plants.
• Top up the watering of an open terrarium, between two waterings.
• Dose water precisely when you build a terrarium, one spray at a time.

In a terrarium, it is the main tool. Our guide watering a terrarium explains how many sprays to give, and when.

What a plant mister does not do

It does not water the root ball

The mist wets the top. It does not reach the roots at the bottom of a pot. A thirsty potted plant needs a real watering at the base, with a watering can.

It does not raise air humidity for long

The University of Illinois is clear: misting gives an unreliable result. Humidity rises for a very short time, and you have to repeat it often. The same source adds that too much misting can encourage leaf diseases.

In winter, the air in a heated home often drops below 30% humidity, according to the University of Illinois. Some tropical plants suffer from it. For them, mist alone is not enough.

Which plants to mist

The Royal Horticultural Society (RHS) lists misting among the ways to help tropical foliage plants that like humid air. It always gives it alongside other steps, such as a tray of wet gravel.

Plants that benefit from mist:

• mosses, in a terrarium or in a pot;
• tropical foliage plants in an open or closed terrarium;
• foliage plants with smooth leaves, to remove dust.

Plants not to mist, or only with care:

• Succulents and cacti. The mist wets the rosettes and the crown without reaching the roots. Water them at the base.
• Plants whose heart holds water. The RHS advises keeping water out of the centre of the bird's nest fern (Asplenium), which can rot.
• Leaves that spot. For some plants, such as the crystal anthurium, the RHS advises against wetting the leaves, to avoid diseases.

If in doubt, mist the air around the plant rather than the leaves.

How to mist well

1. Mist in the morning. The leaves have time to dry during the day. A leaf that stays wet all night is more exposed to diseases.
2. Hold the mister at a distance, so the mist falls in fine droplets. If water runs down the leaves, it is too much.
3. Aim at the mosses and the surface, not at the heart of the plants.
4. Use water at room temperature, never cold water.
5. Let air circulate around potted plants after misting.

In a closed terrarium, mist is mainly for the build, then only when the condensation disappears. A terrarium with water streaming down the glass does not need mist.

What water to put in the mister

Choose soft water: rainwater collected in a clean container, or demineralised water. Limescale leaves white marks on leaves and on glass. In a terrarium, water evaporates and condenses all the time, and the marks build up.

The RHS gives the same advice for some sensitive plants: filtered water or rainwater, because tap water can burn the leaf tips. Our guide which water for a terrarium compares tap water, rainwater and demineralised water.

Empty the mister if you do not use it for several days. Standing water does not stay clean.

For humidity that lasts

The University of Illinois suggests three methods that are more stable than mist:

• The wet gravel tray. Set the pot on gravel, in a tray filled with water. The bottom of the pot must not touch the water. The evaporating water moistens the air around the plant.
• Grouping. Several plants placed together keep more humidity around them.
• A humidifier, for a whole room.

A closed terrarium is another answer. The water circulates in a loop, and the air stays humid with no daily care. To know when to water a pot or an open terrarium, a probe pushed into the soil helps: read our guide to the moisture meter.

Choosing your mister

A few points to help you choose:

• Glass lets you see the water level. It is fragile: set it down flat, away from knocks.
• Metal stands up better to knocks. The supplier lists the copper-coloured model for indoor and outdoor use.
• The 2-in-1 model has a long spout for watering and a nozzle on top for misting. Its spout is too wide for the neck of a closed bottle.

All our misters are delivered empty. Fill them before first use.

In short

1. A mister moistens mosses, foliage and the surface of the substrate.
2. It does not water the root ball, and its effect on the air is short.
3. Mist in the morning, in fine droplets, with soft water.
4. Do not mist succulents or the heart of plants that hold water.
5. For stable humidity: a wet gravel tray, grouped plants, a humidifier or a closed terrarium.

Sources

• Houseplant care, University of Illinois Extension
• Care tips for thirsty houseplants, Royal Horticultural Society
• Manufacturer data sheets (materials, capacities, dimensions, stated uses)