If it gets too hot, like above 80 degrees, the plant growth may speed up but you’ll need to increase watering and fertilizing. It may stretch instead of focusing on growing big buds.
Keep your plants at the high end of the ideal range when they are vegetating, then drop the temperature to the low end for flowering and harvest.
- When you sprout seeds and have seedlings that are beginning to grow roots, give the plants 65 to 70% humidity.
- Once you have leaves and are in the vegetative stage, gradually lower the humidity each week by about 5% until the plants begin to flower.
- At flowering, keep humidity levels around 40 to 50%.
- Then about a week or two before you harvest, lower the humidity more, down to 30 to 40%.
If you’re investing your time and money into raising cannabis, you’ll want to control grow room temperature and humidity to get the best harvest possible. When you grow indoors, you’re the boss of the environment. With the right tools, you can keep things in balance. Digital hygrometers and digital thermometers, and combination monitors, give you the information to precisely control your marijuana’s environment.
Why do you need to lower the humidity as the plants grow? For a couple of reasons—one, too much humidity during the flowering stage can let your plants get moldy. You really don’t want moldy pot. Two, if the humidity hovers around 40% in the flowering stage, the plants will stay thirsty and drink a lot of nutrients and water. (But if you drop below 30%, the plants may react to protect themselves from dehydration. They will go dormant.)
We’ve reviewed a number of different grow room climate control options below. You’ll find simple hygrometers and thermometers; heaters and cooling; humidifiers and dehumidifiers; and full-featured grow room controllers. So, whether you’re on a budget or you’ve got money to invest, read on and you should find just the right grow room control solution for you.
HPS, or high-pressure sodium lamps are great for growing weed, except for two things. They consume a lot of electricity and they make a lot of heat. You can hit over 100 F in a small tent with HPS lamps. If this is your setup, be very careful about monitoring the temperature and using the fan and ventilation system to keep things cool. Also, place your ballasts outside the grow tent if you can.
Just like people, weed feels most comfortable when the temperature and humidity levels aren’t too low or too high. It grows best when it’s between 68 and 77 degrees F and between 40 to 70% humidity. Certain growth periods need a more specific range (but we’ll get to that in a minute). For best growing conditions, you need a hygrometer and a thermometer.
If you use a grow tent, you probably have a relatively well-sealed off area where you have good control over conditions. You may already have a fan or extractor setup, especially if you’re using hot lights like HPS.
Why and how to control temperature and humidity in your grow room. Best hygrometers and thermometers to monitor your marijuana grow space.
Humidity and temperature work hand in hand. In hydroponics you often hear the term “Relative Humidity” or RH. RH is how much moisture is in the air at a given temperature, compared to how much the air could potentially hold at that temperature. So if you see an RH level of 60% at 90 degrees, it means that the air is 60% “full” of moisture. Hotter temperatures can hold larger amounts of moisture, so 60% RH at 90 degrees would be significantly more humid than 60% RH at 60 degrees.
Video Video related to the best temperature & humidity controllers for growing cannabis 2018 2016-05-27T18:03:36-04:00
Watch a video about Autopilot controllers here
If your grow room is kept too cold, your plants simply will not grow to their full potential. If it freezes, they can be damaged or even die. If your grow room is too hot, your plants may become extremely bushy or they may grow long and spindly as they try to dissipate the heat. During flowering stage, too high temperatures can cause terpenes to evaporate. Terpenes are what give different strains their familiar scents and tastes, so you definitely want to preserve them as much as possible.
Titan Controls has a full line of controllers that can fit any budget and grow ops of all sizes. First in line is the Saturn series, which is not being manufactured any more but can still be found in grow rooms and hydroponics shops all over. The Saturn series is extremely reliable and well liked by the growers who use these controls. The Saturn 3 Controller includes temperature, humidity and CO2 calibration features and allows you to hook up three different pieces of equipment. The panel is constructed of analog controls, so it is very durable. The Saturn 6 Controller also allows for temperature, humidity and CO2 control, but this time with a digital control panel. The Saturn 6 has a 15′ remote sensor with photocell and allows for daytime and night-time settings.
- Works wirelessly with your smartphone
- Includes a video camera so you can keep an eye on your crop
- Can be bought as a set or in individual components
Last but not least, we have another affordable controller for smaller sized grow rooms. Even though this controller does not cost as much as some of the other options, it still works very effectively and includes many of the same features. The Element 2 Controller can control your inline fan or dehumidifier, a CO2 generator or any other daytime device of your choice, and a single nighttime device. This controller works especially well when you have a separate timer for your lighting system.
The master controllers below are a huge asset to hydroponic growers, whether you have a large-sized grow op or a modest sized grow tent or cabinet. These devices monitor humidity and temperature levels (and sometimes CO2 levels as well) and hook up to your equipment in order to maintain the perfect level. Usually they do not plug directly into the equipment itself, but a separate timer. For example, you would not plug every single one of your grow lights directly into your master controller. Instead, you would plug your lights into the timer using a daisy chain configuration, and then plug the timer in to the controller.
- Not wireless
- Not good for very large grow ops
Keeping your grow room the right temperature and humidity level is so important when growing cannabis. These master controllers allow you to put your grow room on autopilot.