When you start growing your own weed, one of the first things you learn is the importance of the environment in your grow room. In order to grow a quality crop, you must have control over the temperature and humidity levels that your plants are exposed to throughout their life cycle. This means you need to have the right lighting, ventilation and watering systems, and they all need to be in sync with each other 24 hours a day. Sound complicated? Don’t worry – with the right equipment, it is actually very simple and easy to maintain the perfect environment for your grow op.
Grow tents and grow cabinets make it easy to create an artificial environment for your plants, because they isolate your garden entirely from the outside world – no light gets in or out, and you can add insulation for temperature control. Larger grow ops that take up entire rooms can achieve the same outcome by making sure that doors and windows are sealed and covered. Still, based on the outside environment and the different choices you make when setting up your greenhouse equipment, you may have to deal with problems related to too high or too low temperature or humidity. We’ll go over all of the details below, and then recommend some of our favorite equipment to make environmental controls easy as pie.
Temperature is extremely important for cannabis crops, because it sets the stage for rapid growth when you need it, and proper development of the buds. Cannabis plants like about the same temperature as humans, so if you are comfortable in your grow room, they probably are too.
The specific temperatures that cannabis plants prefer in different stages of growth are:
- Cloning (very young plants): 74 to 77 degrees with no temperature drop at night
- Vegetative (rapid growth) stage: 75 to 85 degrees day time, 65 to 75 degrees night time
- Flowering (developing buds) stage: 65 to 80 degrees day time, 60 to 75 degrees night time
Young plants prefer a higher temperature because it allows them to absorb more moisture out of the air through their leaves while they are developing their root system. Once they start producing flowers, cooler temperatures help to reduce the risk of mold and mildew inside of the moist buds, and keeps the leaves from growing too bushy.
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.
To cool down your grow room, switch to LED lights or increase the ventilation inside of the room. To make it warmer, you can use heating pads, additional lights, or switch to HID lights, which put out more heat than LEDs.
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.
What does this mean for hydroponics? Just like temperature, there are optimal humidity levels for you to maintain throughout your plants’ lives. These levels are:
- Cloning: 70% to 80%
- Vegetative: 40% to 70%
- Flowering: No higher than 40%
If your humidity levels are too low, your plants may end up drinking too much nutrient solution because they are not able to get any moisture through their leaves. This can cause nutrient burn, when plants consume too many nutrients in too short a time, causing wilted leaves with brown edges that look burned. This can lead to crunchy and dried out leaves, which reduces your yield. If humidity levels are too high, it sets your plants up for mold and mildew problems during the flowering stage. If you see or smell any mold on your flowers, they are ruined and need to be thrown away immediately.
To increase humidity, you can increase the temperature in your grow room with lighting or less ventilation, or you can use a misting humidifier to add moisture to the air. To decrease humidity, you can improve your ventilation with a higher powered fan or additional fans, or you can use a hydroponics-grade portable dehumidifier.
Below, we are going to get into the equipment you need to maintain proper levels in your grow room. With the right controller, you can put your ventilation and humidity equipment on autopilot. If you’re starting a cannabis grow op for the very first time, you may also find our guide on how to grow cannabis very helpful. And of course, always make sure you follow all local laws and regulations when purchasing the following materials.
Temperature & Humidity Controllers
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.
1. Budget Friendly: Autopilot Master Controller
The Master Controller from Autopilot is an all-inclusive controller that lets you control up to 4 different devices, and has LED indicators to let you know immediately if anything goes wrong. You can set different temperature and humidity levels for day and night, so that your plants get the perfect environment 24 hours a day. This controller also has a battery backup, so if you experience a power outage you do not have to worry about your settings going back to default.
Price: $148.99 with free shipping
Watch a video about Autopilot controllers here
- Can be used with up to four devices
- Has separate day and night settings
- Has a battery back up for power outages
- No warranty
- Has 3′ temperature probe, larger size not available
- Has a maximum 14.5 maximum Amperage load, cannot be used on larger grow ops
2. Durable and Customizable: Titan Controls Saturn Series
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.
Price: $476.32 to $539.95 with free shipping
Watch a video about the Saturn 6 Controller here.
- Digital or analog control panel available
- Can control CO2 as well as temperature and humidity
- Separate day and night controls
- Not wireless
- Not good for very large grow ops
3. Best Seller: Titan Controls Kronus 4 Controller
The Kronus 4 is an advanced controller with temperature, humidity and CO2 controls. There is a 10 minute delay feature on the CO2 control, to allow for maximum CO2 coverage without any waste. This means you can enter and exit the grow room to adjust the controller levels, change nutrient solution, check on your plants, etc. without worrying about the CO2 escaping through the door. This controller also comes with a 25′ long sensor, so it is perfect for large grow rooms. For grow rooms that are even larger than 25′ long, you can purchase an additional Remote Photocell Sensor for $108.99 that can be placed up to 50 feet away from the controller for accurate readings all throughout your grow op.
Price: $345 with free shipping
Watch a video about this controller here.
- Not as expensive as some other options
- 3 year warranty
- 25′ photocell sensor for large grow ops
- No digital display option
- No customer reviews on amazon
- Price may still be too expensive for small to medium grow ops
4. Top Of The Line: Titan Controls Hyperion 1
Hyperion 1 is the Cadillac of all Titan controls Environmental Controllers. This controller has all of the features you would expect – day/night settings, CO2 integration, temperature and humidity control – as well as some additional exciting features. It is wireless, allowing you to control your grow room settings from up to 150 feet away. It even tells you when your grow light bulbs need to be changed, based on how many hours they have been active.
Price: $653.07 with free shipping
Watch a video about this controller here.
- Wireless control up to 150 feet
- Notifies you when you need to change your bulbs
- Great for large-sized and professional grow ops
- Very expensive
- No warranty
- No reviews on amazon
5. Remote Monitoring: Hydro Crunch Safe Grow Hydroponic Smart System
The Smart System from Hydro Crunch is a bit different from other environmental controllers on this page, because it does not actually hook in to your devices and allow you to schedule them. This is a monitoring system, so that you can have an overall feel for how everything is working in your grow op and be assured that it is all running smoothly. If you have your equipment on individual timers, this is a great addition because it gives you the peace of mind of being able to remotely monitor temperature and humidity levels without having to install a whole new system that hooks up to each device. It even includes a digital video camera so that you can take a look inside of your grow room whenever you want.
Price: $500 with free shipping
- 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
- May be too expensive for smaller grow ops
- No reviews on amazon
- Does not actually control your equipment
6. Easy And Inexpensive: LTL Control Element 2 Environmental Controller
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.
Price: $185.95 with free shipping
- Not as expensive as other options
- 3 year warranty
- Daytime and nighttime settings
- Not good for larger grow ops
- No reviews on amazon
- Cannot control as many devices as other controllers
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