Environmental control - growing cannabis
Growing cannabis is as much about controlling the environment as any other aspect. In my opinion its the most important piece to the puzzle. Controlling your environment and dialing it in at different stages of growth can be the difference between making it to harvest and the quality of your cannabis after your harvest.
There are a whole host of devices and items you should know about before getting into growing cannabis as well as some basic understanding of fixes for a lot of Environmental issues. The last thing you want is to have spent all the money on grow kit and months on a grow only to hit issues or disasters from the very environment you are growing in.
2 growers in the same street can face completely different Environmental challenges depending on the kit, system, or actual area the groom is situated in.
There are rules of thumb or set numbers you will see when researching cannabis growing and the preferred environment for these plants. These are normally around 24-27c in temperature and 40-60% humidity depending on what stage of growth you are in. These numbers are all well and good to aim for but honestly don't lose sleep if you are struggling to hit these numbers on the hottest or coldest days. I will get into why you shouldn't further into this article.
Growing cannabis in an enclosed area is always going to cause issues with the environment. High powered lights, a lot of wet medium or a system full of water, large amounts of plant matter which is breathing and blocking airflow around your grow room as the plants get bigger.
In my years growing, many discussions have come up on forums and elsewhere about people struggling to control the environment in their grooms. I always ask 1 question. What is the temperature and humidity outside of your groom. I'm willing to bet that 99% of the time the tent or groom I much higher than the room the tent or groom is situated in. It's always the answer I get back. The answer is a very simple one and the single most important aspect of growing a plant in an enclosed environment... Air movement.
If you have a tent that's sat at 80% humidity and 34c in temperature that's sat in a room that's 55% humidity and 26c in temperature then you are not moving enough air. If you were moving enough air then the difference between the groom snd the room it's sat in would be much closer. The obvious answer is a bigger extraction system and a good intake system, but this costs money and can create more noise than you would like. Unfortunately, this is likely the only real fix but there are things you can try first.
Air movement can work wonders within the tent or groom. You would be surprised by the dead spots in a packed tent, y dead spots i mean areas where there is next to no air movement due to the angle of the fans in the tent or the amount of plant matter. I'll list a few things I've done to really help negate these dead spots which have helped with high humidity and temperature issues, especially when I've been unable to buy a bigger fan to solve the problem.
Using a fan like the Ram eco louver fans, these have louver fronts meaning they will push and force air all over your tent. Much better than the standard clip-on fans many use.
A fan under the canopy blowing air up through the canopy. Once you are in heavy flower most of us will have a wall of plant matter separating the bottom of the tent. Under here are our pots/systems, lots of damp humid air with not much place to go unless we are forcing it out.
A good defoliation mid flower when I've had high humidity has worked wonders, dropping it massively, with the addition of a fan ushing air up as well its worked miracles.
As already mentioned, if the room your tent is in is lower temps and humidity than your tent but your groom is higher, a bigger extraction is needed. But also as mentioned we can't always afford or cope with bigger fanes. If you have tried all of the above and are still struggling particularly with high humidity you may just have to live with it. If this is the case air movement from inside the tent can work wonders. A huge amount of air movement from fans in the tent will help stop mould set in. This has saved my grows a few times running as high as 80% humidity in late flower.
Summary
The reality is if you are suffering high temps and humidity bigger fans are needed but don't lose sleep if you cant keep it in the correct ranges you see posted around the internet. There are temporary fixes that can and will act as a band-aid 99% of the time as mentioned above. I can tell you now that many growers especially within the recent heatwave are rarely within the correct ranges this plant enjoys are not in the ranges they would want to be. In these cases and in any case, controlling your environment air movement is your best friend.
Once you have big enough fans to compete with the high humidity and high temps it's time to look at fan controllers, but these are more a luxury but will help you in the colder months in particular. I'll do another write-up on fan controllers and ways to combat cold months as they start to kick in.