When it comes to managing a grow room, there are a lot of factors to keep in mind. Plants, just like people, have circumstances they grow in and situations they wither in. Beyond this, if you have different strains of plant or different stages of plant development (seedlings, cuttings, bushes), the needs will vary. The following will explore just one crucial aspect of grow room maintenance—humidity levels. We’ll take a look at what your plants and grow room need in regards to humidity and what you can do about it.
Plants And Humidity
Just like humans, plants need water to grow, and also, like humans, plants respond to the moisture levels in the air. Too much moisture, and you’re looking at mildew, mold, and botrytis risks, too little, and you’re looking at stunted plants with lower yields. To make things even more difficult, plants need different levels of moisture throughout their lives. The following is a very rough guideline, be sure to read up about your particular plant species before choosing humidity levels.
Fully grown plants in the late flowering stage (usually 1 to 2 weeks prior to harvest if they’re producing plants, but this varies depending on your plants and climate) might have you struggling to keep moisture levels down and protect your leaves, stems, and roots from damage. At this point in the growth process, plants like 30 to 40% humidity.
During the flowering period (which will be obvious as there will be flowers on your plants), the ideal humidity range is somewhere between 40 and 50% humidity. Anything about 60% humidity can cause some of the issues we talked about above.
In the vegetation stage, humidity levels can be lowered by around 5% each week. This stage has the greatest flexibility for humidity as anything between 40%, and 70% will work. Keep in mind that as the plant matures, you want to lessen the humidity levels to protect your buds from mold when they begin to grow and ripen.
When it comes to younger plants, nearly the opposite is true. Young plants need somewhere around 65%-70% humidity for ideal growth and development (since they’re so small and their roots are still growing, most of their water absorbed through their leaves). If younger plants are surrounded by air that’s on the dryer side, growth can be stunted, and you’ll end up with lower yields over time.
You Might Need To Separate Plants
As you can imagine, these differences in needs can mean that it’s in your best interest to keep grown plants separated from younger plants so you can give each stage of development the care it needs. If you’re working in a smaller space where you can’t separate them fully, consider working out a clear tenting solution.
Think About The Size Of Your Grow Room
When it comes to selecting a humidifier, there are far more factors you need to take into consideration than you might first imagine. Foremost, you can narrow down the mass of choices available by considering the size of the room you need to keep moist. Most humidifiers will have the square footage they cover written on their packaging and instructions, but a general rule of thumb goes something like this:
- Smaller humidifiers handle up to 300 square feet
- Medium humidifiers cover somewhere around 350 to 500 square feet
- Larger humidifiers can tackle anywhere from 550 to 1000 square feet
Before you begin shopping, take into consideration the size of your space (and measure if you’re anything like us and are terrible at gauging measurements by eye). It might also be prudent to think about whether you plan on expanding the space at any point in the near future.
Choose Between Warm Mist And Cool Mist
Whether or not you choose a warm mist humidifier or a cool mist humidifier isn’t dependent on personal preference. Don’t skip this step! The wrong temperature mist could make things hard on your plants. The perfect humidifier for a grow room or grow tent produces moisture at the perfect temperature. This choice will be made based on the outdoor environment surrounding your grow room. Because you’ll need to be pumping in outdoor air to keep things fresh for your plants, you’ll need to consider the climate in the area you’re growing. If it’s hot out, you’ll want to lean towards the cold mist. If it’s cooler out, you’ll want warm mist. And yes, that means those of us who live in a climate with starkly contrasting seasons; this means you’re looking for a hybrid or for two different humidifiers that you swap out depending on the season.
Learn About How To Clean It Before Purchasing
Humidifiers hold water that they spray out into the air evenly. This means that there’s the risk of bacteria, mold, or mildew growing in or on them. Before making a purchase, you want to do a bit of research on how easy it is to clean. You will have to clean it on a regular basis to ensure that no harm is coming to your plants and not all humidifiers are so easy to take apart, clean, and put back together.
Think About Noise
At first, this might not seem like a big deal to you, but if you (or other people) will be working in the grow room or tent often or if the grow room is part of your living space, you might want to read a few reviews online to make sure that the noise levels are acceptable to you. All humidifiers make noise, but some will make far more noise than others.
The above considerations should help you sort through the countless humidifier options available on the market. Of course, every grow room, every plant, and every grower is slightly different. Always be watching your plants and making adjustments when necessary. We can learn a lot from just observing. Leaves tilt and turn overnight, they droop or tense up, new shoots grow fast or slow—all of these visual indicators will let you know how your plants are doing and what they need. The closer you watch, the more you’ll be able to pick up small differences like how the plant closest to the heater is wilting a bit and needs more water than the others. Always be looking for ways to readjust and improve your growing habits.