Unless you are growing cactus in your grow tent (and in that case, even they need a little water from time to time), then you are going to have to provide a certain level of humidity for your plants.
Grow tents create greenhouse-like simulated environments, which are ideal for growing so many different types of plants. They are usually covered in clear plastic, which allows sunlight to come through. They can also have grow lights that are attached at the top and shine down on top of the plants.
Unfortunately, grow tents can’t produce their own rain or other types of wet weather. So, your plants can suffer from a low relative humidity and you will have to know how to increase humidity in a grow tent.
All About Low Relative Humidity
Not having the proper humidity levels is pretty damaging to your plants because they are living things that require a lot of moisture. Think of how many times you have to water outdoor plants in containers or planted in the soil. That water is usually sucked up through the roots, but plants also get a lot of moisture through their leaves. They’re used to being outside and getting their moisture from the rain.
When the humidity level in your grow tent is too low, it actually pulls moisture out of your plants’ leaves, stems, and vines. Do you have a higher temperature in your grow tent for plants that can’t tolerate the cold? Combining dry air with those warmer temperatures causes a scientific reaction. There is a vapor pressure deficit between what’s going on in the air inside the grow tent and the pressure inherent inside your plants’ leaves.
When your plants aren’t getting enough moisture, they’ll definitely let you know; their leaves will start to curl up and become brittle. You’ll also have more problems with bugs who love to chomp on those drying leaves, not to mention problems with decay.
How do you know when the relative humidity is too low? While your plants’ health is a great factor, you also want to consider purchasing a hygrometer. This handy device measures the percentage of relative humidity.
Many gardeners and growers suggest you have a relatively humidity percentage of around 60%; if your plants are seedlings or very young, that number might even be higher. Research your particular plant’s humidity level requirements.
How to Increase Humidity
The good news is that a grow tent has very few cubic feet of air to raise the humidity, so it is a fairly simple process to raise the levels. You want to do this gradually; raising it quickly might shock your plants too much.
Get a humidifier
The first thing you’ll do is purchase a humidifier that has a built-in humidistat. The humidistat is programmed by you and will automatically stop the humidifier once it reaches your preferred setting.
Set up the humidifier
Set your humidifier on a lower shelf inside your grow tent that’s big enough for the humidifier to sit comfortably without its spray affecting any nearby plants. Run the cord outside the tent to plug it in. Program the humidistat to the humidity level that you want.
Setting up the water supply
In addition to your humidifier, you’ll want to find a small bucket that will sit on top of the grow tent and be filled with water. Then you will need a hose pipe that will run between the water bucket and be connected to the humidifier; make sure it’s long enough to be gravity fed into the humidifier.
Raise the humidity in the grow tent
Fill the bucket with water, have the water go down the hose pipe into the humidifier and continually feed it. Turn the humidifier on. The gentle mist will spray over your plants and help to raise the humidity. Periodically check that neither the humidifier nor the water bucket have run out of water. The humidistat will automatically turn off the humidifier when it’s gotten to the level you programmed it for.
A Simple Setup
While this is a simple set up, it’s surprisingly effective for providing great levels of moisture to your thirsty plants. If you don’t have access to a humidifier or want even simpler solutions, try using clear glass bell cloches over your plants. You can also experiment with removing grow lights, since that can help encourage your plants to hold onto more moisture.
Even providing trays filled with water or soaked sponges can provide a temporary amount of water for your plants. Get creative.