Made in USA
Why Greenhouse Humidity Is Hard to Hold
Sun, ventilation and heating swing greenhouse humidity through the day. Many growers manage it with vapor pressure deficit (VPD), which combines temperature and humidity into one measure of how hard plants are transpiring; a common target for vegetative growth is roughly 0.8 to 1.2 kPa.
How Low Humidity Damages Plants
When the air is too dry, plants lose water faster than their roots can replace it. They close their stomata to save water, which slows photosynthesis and growth, and leaves can wilt, curl or scorch.
Cuttings and seedlings without full root systems are hit hardest, which is why propagation areas are kept more humid.
How High Humidity Damages Plants
When the air is too humid or water stays on leaves, fungal diseases such as botrytis (gray mold) spread more easily.
Plants also transpire less in very humid air, which can reduce nutrient uptake, particularly calcium, and lead to soft growth.
Non-Wetting Humidification for Greenhouses
Smart Fog’s greenhouse fogging system adds moisture as dry fog that evaporates in the air, so humidity rises without the leaf wetness that traditional misting and fogging can leave behind.
Humidity without wet leaves
Dry fog droplets of about 4.2 microns evaporate before they settle, so humidity rises without leaving water on leaves, flowers or benches.
That lets you raise humidity in dry conditions without creating the free water that fungal diseases need.
Even coverage
Fine droplets spread evenly through the house, so plants at the far end get the same conditions as those near the unit.
Sensors and controllers hold your setpoint and adjust as sun, venting and heating change the air through the day.
Cooler on hot, dry days
Evaporation absorbs heat, so on hot, dry days dry fog lowers air temperature, by up to 20°F in very dry conditions, while raising humidity.
The effect is smaller when the air is already humid, and the controls stop adding moisture once your setpoint is reached.
How Humidification Improves Plant Growth
Humidity held in range keeps plants transpiring at a healthy rate, so they take up water and nutrients evenly, keep their stomata open for photosynthesis, and avoid stress from hot, dry air. Combined with good air movement, it also limits the leaf wetness that lets disease take hold.
Benefits of Greenhouse Humidifiers
Getting humidity right does more than prevent problems:
Better nutrient ptake
Even transpiration moves water and nutrients evenly through the plant.
Faster, more even growth
Open stomata and less stress mean steadier photosynthesis and more uniform crops.
Lower disease risk
Humidity held in range without wet leaves gives fungal disease less chance.
Higher yields and savings
Less water stress and crop loss, and no water wasted on wet benches and floors.
Stronger propagation
Cuttings and transplants root and establish better in consistently humid air.
Smart Fog Greenhouse Humidification Systems
From a single house to large commercial greenhouse ranges, systems scale by adding units and work alongside your climate controls.
Choose by how your greenhouse is built:
ES100 Direct Space Humidifier
Mounts on a wall or post to humidify smaller houses and propagation areas directly.
TS100 In Duct Humidifier
Installs in ducted heating or ventilation to humidify the air as it is distributed.
ES100M Portable Industrial Humidifier
A portable unit on wheels for propagation benches and seasonal needs.
MS100 Custom Grid System
A custom grid for large ranges, covering up to 10,000 sq ft per system.
Simplify Greenhouse Humidification
Smart Fog has built humidification systems for more than 40 years, and every system is made in the USA. Tell us about your crops and your house, and we will size a system to your targets.
FAQs
What humidity should a greenhouse be?
It depends on the crop and growth stage. Many growers manage to a VPD of roughly 0.8 to 1.2 kPa for vegetative growth, which at 75°F is roughly 60 to 75% RH. Propagation areas are usually kept more humid.
Will this system cause condensation or wet leaves?
No. Dry fog evaporates before it settles, and the controls stop adding moisture once your setpoint is reached, so leaves and benches stay dry.
What is the best humidifier for a commercial greenhouse?
One that raises humidity without wetting leaves, holds a setpoint automatically and covers the whole house evenly; dry fog does all three. Small houses and propagation areas can start with a single wall-mounted ES100 or a portable ES100M, and large ranges use a custom MS100 grid.
How much energy does a greenhouse humidifier use?
About 0.4 kW per unit at full output, while adding up to 25 lb of water an hour. Upkeep is mainly water filter changes and inspection.
Can it cool my greenhouse?
Yes, in dry conditions. Evaporation can lower air temperature by up to 20°F when the air is very dry; the effect is smaller in humid weather.