Indoor Cultivation Specialist
There are two environmental factors important to every successful cannabis grow: temperature and humidity. We are surrounded by them every day, and we certainly can feel it when it’s too hot or dank and humid for us. Your precious little plants can too.
When we are hot, we sweat, which causes us to drink water to replenish ourselves. By maintaining grow room temperature control, we can encourage our plants to transpire (the equivalent of sweating). When our plants are sweating from the underside of the leaves, the plant reacts by taking up more water from the root zone
The root zone is where we add our plant nutrients, and when the plant is taking up water from the root zone, it is also taking in nutrients. By understanding indoor climate control, we can increase our plants' health and yields through increased nutrient uptake.
You might be thinking, if I make my grow room conditions really hot, my plant will sweat a ton and uptake mega doses of nutrients and be super big…. but that's not a good idea.
First off, the seedling stage will benefit from warm temperatures. The additional humidity in the air is beneficial to the growth above the surface, but the warmer temperatures also encourage seed germination and root growth. If the temperature is too cool during this stage, growth can slow, pathogen pressure can increase, and that can lead to damping off (seedling death). The ideal temperature range for a cannabis seedling is 21-28 °C (70-83 °F).
Driving growth in the vegetative stage is directly related to the number of flowers you will harvest later. Grow room temperatures are similar to those of the seedling phase. The goal of using this temperature range is to increase transpiration (plant sweating) and drive nutrient uptake from the root zone. This will help the plant grow sturdy branches and plenty of bud sites. The ideal temperature range for cannabis in the vegetative stage is 21-28 °C (70-83 °F).
Part of controlling your humidity is controlling your temperature. Tools like an exhaust fan and the internal circulating fan(s) not only help control temperature but they assist in the fight against high humidity too. Dehumidifiers can be used to lower the humidity of the grow tent or lung room. Just the same, humidifiers can be used to increase humidity if needed.
The more soil you have in a grow tent, the larger the amount of moisture that will be released into the atmosphere through evaporation. I like the idea of growing in beds instead of pots, but even a 3x3 bed of soil in a 4x4 grow tent creates an almost unconquerable battle with humidity because of the large soil mass and all of the moisture it is capable of retaining. So, if you have a small tent, I recommend you stick to growing cannabis in pots!
Most tent growers are growing inside a house or apartment, which provides a unique opportunity for controlling grow room conditions. Using the existing heating and cooling systems of the house, the lung room (the room your tent sits in) can be kept within the ideal ranges, conditioning the air inside of the grow tents.
Manufacturers of cannabis grow equipment are creating automated systems that enable growers to set their grow room climate controls and let the machines handle the rest. If the temperature goes above the maximum setting, the A/C will turn on. If the humidity exceeds the set level, it will increase the exhaust fan speed and/or activate the dehumidifier. If it is too cold, the heater will turn on. Humidity too low? It will activate the humidifier. The amount of automation is incredible, and I expect to see more manufacturers adopting this technology.
A new grower might assume that the smaller the grow tent, the easier it will be to control temperature and humidity. The opposite is actually true. Smaller spaces take less time to heat up from the equipment and less space for plant transpiration to go. So, first, consider the size of your grow tent. I find that the climate is easiest to control in grow tents 4x4 or larger.
“Aside from these, you may need a humidifier, dehumidifier, space heater, or even a small A/C unit depending on the climate where you live.”
| HPS Wattage | LED Wattage | Ideal Area (m2) |
|---|---|---|
| 150W | 100W | 0.6 m2 |
| 250W | 150W | 0.8 m2 |
| 400W | 250W | 1.0 m2 |
| 600W | 400W | 1.2 m2 |
| 1000W | 600W | 1.5 m2 |
The germinated seeds peak out above ground and immediately spring up.
Just another couple of months of blossoming we will be ready to get our sheers ut of the cupboard.
Harvest time might seem like the end of a long journey, your buds have ripened, and now it's time to smoke up.
