Cannabis Environment & Climate Guide

The grow room climate consists of the balance between heat, humidity, and air movement within your grow space. It is one of the most important aspects that you will need to take into considertion when planning your garden. Your success will depend on how well your climate works to serve the needs of your plants. 

Humidity is the amount of water vapor in the air. Its what makes the air outside seem muggy or soupy and has a list of effects on flora.

Primarily, the humidity of your grow space will determine the rate at which your plants transpire. Transpiration denotes the movement of water throughout a plant, followed by its evaporation from the leaves, stems, and flowers. This mechanism operates passively without the plant expending energy. Notably, transpiration plays multiple roles: it aids in cooling plants, alters the osmotic pressure within cells, and facilitates the mass flow of essential mineral nutrients.If your humidity is too high, it can become saturated, meaning that the air won't accept any more water and so your plant isn't able to transpire properly. 

Cannabis during the Veg cycle likes the humidity to be between 55-700%. For flowering, we like to see the humidity stay in the 40-55% range. This drop in humidity gives us a bit more protection from mold in our buds while also providing ideal conditions for resin and terpene production. To monitor and maintain your grow spaces humidity we recommend a tool like the Active Air Thermometer & Hygrometer combo. This handy little gadget will provide you with an on demand measurement of your space's temperature and humidity. It also includes a remote probe for readings in multiple areas. 

One way to completely cut out the guesswork is with a fully automated smart tent kit, like the AC Infinity Advanced Grow Tent line. These tents come with a built in smart controller that connects to your climate control components and activates them when the conditions in your tent demand. Theres even a humidifier available that connects to the smart controller on your AC Infinity tent that will automatically activate when the sensors read that the humidity is too low.

Apart from a few rare heirloom strains, cannabis grows best between 65-75 degrees fahrenheit. Certain strains may like it a little warmer, but research into the strains you want to grow will provide you with their optimal temps. 

Temperature plays into the success of your garden by controlling the evaporation of water, and the transpiration function of your plants. Too hot and your plants will transpire too much water and won'tbe able to keep up. This can cause leaf curl, wilting, or even death of your plants. You can often times find yourself constantly watering in a hot garden as well. Couple a high temperature with a high humidity and you've got the perfect recipe for mold and algae growth. 

Where does the heat come from you may ask? The number one source of heat in your grow room will be from your light. Depending on how efficiently your light turns elctricity into usable light will determine how much heat that light will produce. Less efficient options like High Pressure Sodium (HPS) or Metal Hallide (MH) may offer a lower upfront cost, but create more heat waste per lumen than an LED which typically run very cool. This is due to the light source (Bulb) and ballast not being able to convert all of the electricity it is using into light, so it releases this wasted energy as heat. Choosing a ventilation system with enough air movement for your space will allow you to remove heat as it is being produced, no mater what type of light you are using. 

Check out our section dedicated to Climate Control to browse our top products!

By knowing our heat gain and heat loss ratios, we can determine when and how fast our fans need to turn on and run. if your ambient temperature is 70 degrees and your light produces 100 BTUs, then you will need to ventilate to account for that extra heat. Many systems like AC Infinity's Advanced Grow Tent Kit or MarsHydro's IFresh line automatically monitor and activate your fans, heaters, or A/C unit if you have them as a part of your setup. 

Temperature is a very important aspect to any garden. Plants will transpire (water loss through evaporation) more rapidly in higher heat conditions. Our soil will also dry much quicker and will cause humidity to rise in the garden. It's ideal to keep temperatures in the 65-75 range in order to keep our plants from drying out and our humidity to stay within range. If ventilation alone isn't enough to cool our gardens, small A/C units can be added to your space. 

Humidity interacts with the rate at which our plants transpire water vapor and waste gasses from the plant, A humid climate will cause transpiration to happen at a slower rate than a dry climate would, If the humidity gets too high however, it opens up problems like mold, mildew, and the damping off of your seedlings. 

Humidity during the vegetative state should be between 55% and 70% and between 40% and 55% for flowering. Just remember, the lower the humidity the higher the transpiration and the more attractive your buds will be to flies and mites. The higher the humidity the higher the risk of mold and bud rot. Keep to the ranges we've recommended and ensure that air is constanly being circulated and you will be just fine. To be accurate when measuring your humidity, consider investing in a Hygrometer to monitor the humidity in your garden.

You can use a device called a Hygrometer to measure both the humidity and the temperature of your garden. Some kits like AC Infinity's Advanced Grow Tent Kit and MarsHydro's iFresh line will monitor your garden for you and activate your climate control automatically, keeping your climate at the right level.

With a smart system like AC Infinity's Advanced Grow Tent Kit, You can set exact temperature and humidity parameters to hone in on your strain's ideal growing climate conditions. These tents come with a fully automated controller that links to the different climate components in your garden, activating them when the need comes. 

From inline fans to lights and even humidifiers, AC Infinity's Controller 69 PRO+ directly links to each climate component to monitor and control each aspect of your tent's climate measures in sync. We highly recommend these smart systems as they can drastically improvethe quality of your first grow and ease you into the process while taking care of some of the more tricky functions of your space. 

Directly, your hygrometer, fan, humidifier, and heater- A/C unit will control your climate. Other things like lights and heating pads will affect your climate indirectly. The ambient temperature surrounding your grow space also affects what goes on in your gardens climate. You can exhaust all day long, but if the intake air is hot, you won't be able to cool your space. These circumstances need to be taken into account during the planning stage so that you have no hidden surprises when it comes to fill your space with plants.

If the climate is off in your tent, you might notice things like leaf curl, root rot, mold, "burning" of leaves and flower, scaly stems and stalks, or weak stems and stalks. 

If you have root rot or mold growing in your garden, your plants are trying to tell you that its too humid and potentially too hot. Mold and mildew love humid spaces that are kept warm. A toasty grow tent full of moisture is the perfect breeding grounds.

If you are noticing your leaves curling up or turning leathery with dead tips, your garden is too warm and the plants can't keep up with the rate of transpiration. 

If the stalks of your plants seem flimsy and weak, there probably isn't enough airflow in your tent to develop strength in the stems. Add a oscillating fan to keep air moving through the garden. 

Keep a close eye on your climate with a Hygrometer, which will monitor the temperature and humidity in your garden.