The most effective way to increase humidity for houseplants is to use a humidifier placed in the same room. Misting, pebble trays, and grouping plants help at the margins but cannot replicate the steady, ambient moisture a humidifier provides. That said, many plants will do fine without one if you follow the other methods consistently and avoid placing them next to radiators or draughty windows.
Here is what actually works, what is overrated, and how to match the method to the plants you grow.
Why humidity matters for houseplants
Most popular tropical houseplants originate from rainforest environments where relative humidity regularly sits between 60 and 90%. UK homes in winter typically hover between 30 and 50%. For humidity-sensitive plants like Calathea and Alocasia, this gap shows up as brown leaf edges, crispy tips, and poor new growth.
Not all houseplants care equally. Most succulents are comfortable in average household humidity. The plants that genuinely benefit from higher humidity are your aroids, ferns, calatheas, and other moisture-loving tropicals. Before investing in equipment, it is worth knowing which of your plants actually need the boost and which do not.
Use a humidifier
A humidifier is the only method that reliably raises ambient room humidity to the 50 to 70% range that humidity-sensitive plants prefer. Place it in the same room as your plants, ideally not directly next to them as you will want to raise the whole room's humidity rather than drench a single plant.
Ultrasonic humidifiers are the most common type for home use as it is quiet, energy-efficient, and easy to clean. Look for one with a built-in hygrometer (humidity sensor) so you can monitor levels without guessing. The VIVOSUN AeroStream H05 Humidifier is a solid compact option for smaller rooms, while the VIVOSUN AeroStream H19 is better suited to larger spaces and has intelligent environmental controls.
Always use distilled or filtered water in your humidifier to prevent mineral deposits building up in the unit and on your plant leaves. Empty and clean the reservoir regularly to prevent mould and bacteria growth.
Group your plants together
Plants release water vapour through their leaves as part of transpiration. When you group plants close together, they collectively raise the local humidity around them. This effect is modest — it is not going to get you from 40% to 70%, but it is the more affordable option.
Pebble trays
A pebble tray is a shallow tray filled with small stones or pebbles and water, with your plant pot sitting on top of the stones rather than in the water. As the water in the tray evaporates, it raises the humidity immediately around the plant.
This method works best in still air and close proximity to the plant. Its effect is localised and it primarily benefits the plant sitting above it. For a few plants in one spot, it is a low-effort and inexpensive approach. Keep the water level below the base of the pot at all times to prevent the roots wicking up moisture and staying too wet.
Bathroom and kitchen placement
Bathrooms and kitchens are naturally more humid than other rooms because of showers, cooking, and running water. If you have a bathroom with adequate light (even indirect light from a frosted window), it is often an ideal spot for humidity-loving plants. Ferns, Alocasia, and Calathea thrive in bathroom conditions.
The important caveat: the humidity boost only helps if the light is sufficient. A beautiful Calathea in a dark bathroom with no natural light will struggle far more from light deprivation than from any humidity benefit. Light comes first as it is needed for photosynthesis.
Does misting houseplants help with humidity?
Misting is probably the most talked-about method for increasing humidity, and in our opinion, the least effective. The moisture from misting evaporates within minutes, providing only a very brief and localised spike in humidity. To maintain even moderately elevated humidity through misting alone, you would need to mist every hour or so, which is impractical.
There are also plants you should not mist at all. Plants with hairy or velvety leaves like Anthurium and Gynura can quickly develop fungal spots and rot when water sits on the leaf surface. Plants with open growth forms where water gets trapped in the crown can also suffer. For most plants, misting is harmless but largely cosmetic.
The one case where misting is genuinely useful is when you have recently repotted a cutting or a plant is recovering from transplant stress — a light mist helps keep the leaves hydrated while roots re-establish. See our guide to whether you should mist your houseplants for a fuller breakdown.
Avoid placing plants Near radiators
This is less about increasing humidity and more about not actively reducing it. Central heating is the single biggest driver of low indoor humidity in UK homes. A plant placed directly next to or above a radiator will have its leaves dried out by the warm air, and the compost will dry out far faster than expected.
Move humidity-sensitive plants at least 1 to 2 metres away from active radiators. The same applies to air conditioning units, which dehumidify the air as they cool it. See our article on whether houseplants hate draughts and radiators for more on positioning.
Which houseplants actually need higher humidity?
In our experience, the plants that genuinely show a meaningful response to humidity management are:
- Calathea and Maranta: Both are extremely sensitive to dry air. Brown, crispy leaf edges within days of being placed near a radiator are a tell-tale sign. Aim for 60% or above.
- Ferns: Boston ferns, bird's nest ferns, and most other fern species want consistently moist air. They are among the best indicator plants for humidity — if the tips are browning, the air is too dry.
- Alocasia and Colocasia: Prefer high humidity but will often tolerate standard household conditions if kept away from heat sources. Crispy leaf margins are the warning sign.
- Philodendron and Monstera: More tolerant of average humidity than their reputation suggests. Most Philodendrons will grow perfectly well in a typical UK home without intervention. Aerial root browning is sometimes humidity-related.
- Most succulents and cacti: Do not increase humidity for these. They actively prefer dry air and will suffer in a consistently humid room.
What humidity level should you aim for?
For general houseplants, 50 to 60% relative humidity is a comfortable target. Most homes achieve this naturally in summer and struggle in the heating season. For the most humidity-demanding plants pushing toward 60 to 70% makes a noticeable difference to leaf condition.
A small digital hygrometer is worth having if you are serious about growing humidity-loving plants. It removes the guesswork and lets you know whether your methods are actually making a difference.