Grow Room Help

To Humidify or De-humidify? … That Is The Question

A lot of gardeners swear by it but some think it’s a waste of time. In this weeks blog we are going to explore the reasons why you need to monitor your grow rooms humidity levels and if doing so will improve your plants growth rates.

In order to be successful when growing plants you need to make sure you have the ideal growing conditions. First you need the ideal growing area, then the perfect lighting and finally an effective extraction system that’ll remove and extract odours, heat and harmful airborne pathogens. However, you also need to introduce and monitor the correct ranges of humidity in your growing area. Below is a few things what can happen if you have the wrong humidity levels.

Low humidity levels:

  • Stunt growth and impact a plants ability to grow and produce crops
  • Low moisture on a plants leaves can apply more pressure which will subsequently reduce the plants life span
  • Low humidity allows pests and bugs to thrive as well as molds and mildew

High humidity levels:

  • Perfect environment for mold and bacteria to grow
  • Impacts the plants ability to effectively transpire
  • Roots can not absorb water, they become dormant and root rot can set in


How is best to manage grow room humidity?

The best way to manage your humidity levels is to get yourself a piece of equipment that monitors humidity levels. One of the most popular pieces of equipment is Thermo-Hygrometer HTC-2  as it monitors humidity as well as a grow rooms temperature and is also easy on the wallet. However, if you want to splash out there are numerous other high end humidity monitors available. Below are some ranges which you should keep your plants at when they are at certain stages of their development:

  • 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 increase your humidity levels, purchasing a humidifier or humidity pack is the easiest way of doing this. In addition, if you need to lower humidity levels you can simply buy a low cost Dehumidifier.


To conclude, many gardeners concentrate on lighting, nutrients and extraction systems and often overlook their grow rooms humidity levels which then impacts their plants healthy. By ensuring a grow rooms humidity stays at optimal levels, gardeners can enjoy healthy plants that produce large crops.

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