Humidity control is essential for maintaining a healthy indoor growing environment. The right humidity levels support plant growth, improve nutrient uptake and help prevent issues such as mould, mildew and plant stress.

At Acorn Horticulture, we supply a wide range of humidity control products in the UK, including humidifiers, dehumidifiers and monitoring equipment. Whether you are growing in grow tents, using grow lights or running hydroponic systems, maintaining the correct humidity levels is key to achieving strong, healthy plant growth.

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RAM Dehumidifiers 12L & 20L UK | Grow Room & Grow Tent Dehumidifier

Price range: £169.00 through £195.00 incl. Vat
Select options This product has multiple variants. The options may be chosen on the product page

The RAM Dehumidifier range is designed to control excess humidity within grow rooms, grow tents, drying rooms, hydroponic environments, and indoor cultivation spaces. Available in 12L and 20L models, these powerful dehumidifiers help prevent mould, mildew, condensation, and bud rot while maintaining stable environmental conditions for healthier plant growth and improved drying performance.

  • Available in 12L and 20L extraction capacities
  • Removes excess moisture from grow environments
  • Helps prevent mould, mildew & condensation
  • Ideal for grow rooms, drying rooms & hydroponics
  • Built-in humidistat with automatic humidity control

RAM Humidifier 13L / 5L UK | Ultrasonic Grow Room Humidifier

Price range: £45.00 through £120.00 incl. Vat
Select options This product has multiple variants. The options may be chosen on the product page

The RAM Humidifier 13L / 5L is a professional ultrasonic humidifier designed for grow rooms, grow tents, propagation chambers, hydroponics, and indoor cultivation environments. Available in both 5 litre and 13 litre models, these humidifiers provide adjustable cool mist humidity control to help maintain ideal growing conditions for seedlings, cuttings, vegetative growth, and healthier plant development.

  • Available in 5L and 13L tank capacities
  • Ultrasonic cool mist humidifier technology
  • Adjustable humidity output control
  • Quiet operation for grow rooms and grow tents
  • Ideal for seedlings, cuttings & vegetative growth

Grow Bitz 4.5L Humidifier UK | Ultrasonic Grow Room & Grow Tent Humidifier

Original price was: £49.50.Current price is: £39.50. incl. Vat

The Grow Bitz 4.5L Humidifier is a compact ultrasonic humidifier designed for grow rooms, grow tents, propagation areas, and hydroponic environments. Featuring a large 4.5 litre tank capacity, adjustable mist output, and quiet cool mist operation, this humidifier helps maintain stable humidity levels for seedlings, cuttings, vegetative growth, and healthier indoor growing conditions.

  • Large 4.5 litre water tank capacity
  • Ultrasonic cool mist humidifier technology
  • Adjustable humidity output control
  • Quiet operation for grow tents and grow rooms
  • Ideal for seedlings, cuttings & vegetative growth

RAM Wall Humidifier UK | Ultrasonic Wall Mounted Grow Room Humidifier

Original price was: £259.00.Current price is: £219.00. incl. Vat

The RAM Wall Humidifier is a professional ultrasonic wall-mounted humidifier designed for grow rooms, grow tents, propagation areas, greenhouses, mushroom rooms, and hydroponic environments. Featuring powerful 1600ml/hr mist output, adjustable humidistat control, and direct mains water connection, this high-capacity humidifier provides reliable automatic humidity management while saving valuable floor space.

  • Powerful 1600ml/hr ultrasonic humidifier output
  • Wall-mounted design saves floor space
  • Adjustable humidistat control from 20–100% RH
  • Direct mains water connection – no refilling required
  • Ideal for grow rooms, propagation & hydroponics

Mist Maker 5 Pin Float 400ml/hr UK | Ultrasonic Grow Room Humidifier

£110.00 incl. Vat

The Mist Maker 5 Pin Float 400ml/hr is a powerful ultrasonic humidifier designed for grow rooms, grow tents, propagation systems, hydroponics, and terrariums. Producing a fine cool mist using ultrasonic vibration technology, this humidifier helps maintain optimal humidity levels for seedlings, clones, and vegetative growth while operating quietly and efficiently. Supplied with a float system for automatic water level positioning, it provides reliable humidity control for indoor growing environments.

  • Ultrasonic humidifier with 400ml/hr mist output
  • Includes float for stable water positioning
  • Produces ultra-fine cool mist without heat
  • Ideal for propagation, seedlings & vegetative growth
  • Quiet operation for grow rooms and grow tents

Mist Maker 3 Pin Float 240ml/hr UK | Ultrasonic Grow Room Humidifier

£69.00 incl. Vat

💧 Mist Maker 3 Pin Float 240ml/hr Guide & Product Information

🌱 Ultrasonic Humidity Control for Grow Rooms & Propagation

The Mist Maker 3 Pin Float 240ml/hr is a compact ultrasonic humidifier designed to increase humidity levels within grow rooms, grow tents, propagators, cloning systems, and hydroponic environments.

Using ultrasonic vibration technology, the Mist Maker produces an ultra-fine cool mist without using heating elements. This creates ideal humidity conditions for seedlings, cuttings, young plants, and vegetative growth stages where higher relative humidity is essential for healthy plant development.

Maintaining correct humidity levels helps reduce plant stress, improve transpiration, encourage faster rooting, and support healthier vegetative growth.

The included float automatically maintains the Mist Maker at the correct water depth, ensuring reliable and efficient operation as water levels change within the reservoir. :contentReference[oaicite:0]{index=0}

If you are improving your grow room environment, read our guide to maintaining optimal temperature and humidity in your grow tent.

  • Produces ultra-fine cool humidity mist
  • Ideal for propagation and vegetative growth
  • Quiet ultrasonic operation
  • Includes float for stable water positioning

💨 Ultrasonic Mist Technology

The Mist Maker uses ultrasonic ceramic disc technology to create microscopic water droplets that disperse into the air as a fine cool mist.

The ultrasonic discs vibrate at extremely high frequencies, breaking water into tiny airborne particles without using heat. This creates humidity quickly and efficiently while keeping grow room temperatures stable. :contentReference[oaicite:1]{index=1}

Benefits of ultrasonic misting include:

  • Fast humidity increase
  • Cool-running operation
  • Very fine micron-sized mist particles
  • Low energy consumption

Unlike heated humidifiers, ultrasonic systems do not significantly raise grow room temperatures.

🌿 Perfect for Seedlings & Cuttings

Young plants and fresh cuttings require elevated humidity levels to prevent dehydration and encourage rapid root development.

The Mist Maker creates ideal environmental conditions for:

  • Seedlings
  • Cuttings and clones
  • Vegetative-stage plants
  • Propagation domes and propagators

Maintaining proper humidity during propagation helps:

  • Improve rooting success
  • Reduce plant stress
  • Encourage faster vegetative growth
  • Improve nutrient transport within plants

Mist Makers are commonly used within large propagators and small grow tents to maintain high humidity levels. :contentReference[oaicite:2]{index=2}

⚡ 240ml/hr Mist Output

The Mist Maker produces approximately 240ml of mist per hour, making it suitable for:

  • Small grow tents
  • Propagation chambers
  • Cloning systems
  • Grow spaces up to approximately 2.4m x 1.2m

This output level provides effective humidity support without over-saturating the environment when used correctly. :contentReference[oaicite:3]{index=3}

🛟 Included Float System

The included float automatically keeps the Mist Maker positioned at the correct water depth within the reservoir.

As water levels drop, the float lowers with the water while maintaining ideal ultrasonic operating depth. This:

  • Improves operational stability
  • Prevents incorrect water positioning
  • Allows use in larger reservoirs
  • Reduces maintenance requirements

The float makes the system far easier to manage compared to fixed-position humidifiers. :contentReference[oaicite:4]{index=4}

🔇 Quiet & Cool Running Operation

The Mist Maker operates quietly without heating elements or loud fans, making it ideal for indoor grow environments.

Benefits include:

  • Quiet operation for grow tents
  • Cool-running humidification
  • No heating element required
  • Suitable for continuous propagation use

The unit also features automatic shut-off protection if water levels become too low. :contentReference[oaicite:5]{index=5}

📏 Technical Specifications

  • Mist Output: 240ml/hr
  • Ultrasonic ceramic disc technology
  • Includes float system
  • Cool mist operation
  • Quiet operation
  • Automatic low water shut-off
  • Standard UK 3-pin plug connection
  • Suitable for hydroponics and propagation systems

🌬 Benefits for Indoor Growing

The Mist Maker helps growers maintain healthier and more productive propagation environments.

Benefits include:

  • Improved propagation success
  • Faster root development
  • Reduced seedling stress
  • Better vegetative growth conditions
  • Stable humidity control

❓ FAQ

What does the Mist Maker do?
It increases humidity by producing a fine ultrasonic cool mist within grow rooms and propagation environments.

What is the output of this model?
This model produces approximately 240ml of mist per hour. :contentReference[oaicite:6]{index=6}

Does it include a float?
Yes, this version includes a float which maintains the correct operating water level.

Is it suitable for propagation?
Yes, it is ideal for seedlings, cuttings, cloning systems, and vegetative growth stages.

Does it use heat to create humidity?
No, ultrasonic vibration technology creates cool mist without heating elements. :contentReference[oaicite:7]{index=7}

Max/Min Thermometer Hygrometer UK | Grow Room Temperature & Humidity Monitor

£10.00 incl. Vat

The Max/Min Thermometer Hygrometer is a digital environmental monitor designed for grow rooms, grow tents, greenhouses, propagation areas, and hydroponic systems. Featuring simultaneous temperature and humidity readings with maximum and minimum memory recording, this easy-to-read monitor helps growers maintain stable environmental conditions for healthier plant growth and improved propagation success.

  • Displays temperature and humidity simultaneously
  • Max/min environmental memory function
  • Ideal for grow rooms and grow tents
  • Helps maintain stable grow room conditions
  • Suitable for hydroponics, propagation & greenhouses

Why Humidity Is Important in Indoor Growing

Humidity plays a vital role in plant growth by affecting how plants absorb water and nutrients. It directly influences transpiration, which is the process plants use to move water through their system.

When humidity levels are balanced, plants can grow efficiently and remain healthy. If levels are too high or too low, it can lead to stress, poor growth and increased risk of disease.

Ideal Humidity Levels for Plant Growth

Different stages of growth require different humidity levels. Maintaining the correct range helps plants develop properly:

  • Seedlings and clones – high humidity (around 65–75%)
  • Vegetative stage – moderate humidity (around 50–65%)
  • Flowering stage – lower humidity (around 40–50%)

Keeping humidity within these ranges helps improve plant growth, nutrient uptake and overall health.

Problems Caused by Incorrect Humidity

Humidity that is too high or too low can cause serious issues in your grow space:

  • High humidity – increases the risk of mould, mildew and fungal diseases
  • Low humidity – can lead to dehydration, plant stress and slower growth
  • Unstable humidity – causes inconsistent plant performance

Maintaining consistent humidity levels is essential for preventing these problems and ensuring healthy plant development.

Types of Humidity Control Equipment

There are several types of products used to manage humidity in indoor growing environments:

  • Humidifiers – increase moisture levels in dry environments
  • Dehumidifiers – remove excess moisture to prevent mould and rot
  • Hygrometers – monitor humidity and temperature levels
  • Climate controllers – automate humidity management

Using the right equipment allows you to maintain stable conditions throughout the growing cycle.

Humidity and Ventilation

Humidity control works closely with your ventilation system. Plants naturally release moisture into the air, which can quickly build up in enclosed spaces.

For best results, combine humidity control with:

This combination helps maintain a balanced and controlled environment.

How to Control Humidity in a Grow Tent

Managing humidity requires regular monitoring and adjustment. Simple steps include:

  • Using a hygrometer to track humidity levels
  • Adding a humidifier in dry conditions
  • Using a dehumidifier during flowering stages
  • Improving airflow and ventilation

Consistent monitoring allows you to keep conditions within the ideal range and avoid sudden changes.

Helpful Guides for Humidity Control

If you want to learn more about managing humidity, explore our guides:

These guides will help you create the perfect indoor growing environment.

Shop Humidity Control Products in the UK

At Acorn Horticulture, we stock a wide range of humidity control products for indoor growers across the UK. From humidifiers and dehumidifiers to monitoring tools and controllers, our range is designed to help you maintain the perfect balance of moisture in your grow space.

Browse our full selection above to find the right humidity control solutions for your setup.

FAQs

What is the ideal humidity for indoor plants?

Most plants thrive between 40–60% humidity, depending on the stage of growth.

How do I increase humidity in a grow tent?

You can use a humidifier, water trays or reduce airflow to increase humidity levels.

How do I reduce humidity in a grow room?

Use a dehumidifier and improve ventilation to remove excess moisture from the air.

Why is humidity important for plant growth?

Humidity affects water uptake, nutrient absorption and overall plant health.