Humidify or De-humidify.....

In order to gain success when growing your favourite plants, flowers or vegetables in hydroponics, all bases needed to be covered. There is no sense for example having powerful lights and insufficient extraction – or pulling too much air from the grow area with over sized extraction fans....

So today I am going to look at grow room humidity control, which is so often overlooked as many growers focus on lighting. Indoor growing is a balancing game - played by many growers 365 days a year – successfully!

Many customers do not know the importance of maintaining the correct ranges humidity throughout all plant growth stages - and when they’s too late. Below is a list of what can happen when you are not monitoring or controlling grow room humidity levels:

Low humidity levels :

  • Slow plant development and stunted growth
  • Low moisture on leaves puts more pressure on plant – shorten life
  • Encourages Spider mites, molds and mildew

Very High humidity levels:

  • Perfect environment for molds and bacteria growth
  • Stops plants from effectively transpiring
  • Roots are no longer able to absorb water and become dormant
  • Plant stomata becomes blocked causing a reduction in carbon dioxide

How to manage grow room humidity?

Once you aware of your humidity levels you when then be able to determine if you Humidify or De-humidify – your grow room area or tent. The AirComfort (see previous post here) is perfect for obtaining this vital information providing you temperature and humidity levels for up to 100 days. Its vital to keep within the below ranges according to plant development stage below:

  • 70-80%  - after you see the first leaves
  • 40-70% - during the vegetative stage
  • 40-50% - during the flowering stage
  • <40% - in the last week before harvest

If you need to raise your grow room humidity then investing in Humidifier is the easiest way, we offer humidifiers starting from £37.95. Filling your grow area with a cool mist at timely intervals some models are wall mountable and can be connected to a water source for continuous use removing the need to refill the tanks.

When it comes to lowering grow room humidity our De-humidifier range start starts at £149.95 for the RAM 10L Dehumidifier and features a Continuous drainage option meaning you can deliver the collected water to waste directly, removing the need to empty the 10L tank manually. These units not only will they remove excess moisture present in the indoor growing area – but you can program your desired humidity level and unit will maintain it.


So many issues are caused by over lighting, lack of ventilation and no consideration for the plants ability to grow healthy and stress free. By ensuring that you are in the correct ranges for humidity according to plant development you can enjoy problem free growing!

Getting dialled in to your plants requirements isn’t difficult – all the tools are available.....and remember prevention is better than powder mildew or spider mites :)