Growing indoors has been gaining popularity as governments have slowly begun to legalize the recreational and medicinal cultivation of cannabis. Though if you are new to the venture, you are likely among the majority who are simply unsure of what equipment to use, where to get it, and how many plants your equipment will allow you to grow. Choosing a grow tent size is the beginning of your success as a personal grower, and there are several factors you need to consider before hastily buying a grow tent on Amazon because of a ‘hot sale.’ The biggest considerations you will have are the dimensions of your grow space, what plants (or strains) you will be growing, what kind of yields you are expecting, what kind of lighting you plan to purchase and what style of plant training you will be using. Let’s take a look at each of these considerations separately.
1. The Dimensions of your grow space
Don’t assume that just because you have a 2x4 foot closet space to grow that you should buy a tent this size. First of all, the tent sizes listed online are often rounded estimates based on a conversion from centimeter dimensions. The tent that arrives at your door very well could be larger than the space you expected it to fit in. Secondly, even if the tent is actually 2x4 foot, this will still not fare well in a 2x4 foot space. Why? This is because a large component of growing indoors is ensuring you are fostering the proper environment for your plants, and this includes airflow. Passive air inlets and ventilation ports on a grow tent are found at the sides and back of the tent. Therefore if you place a 2x4 tent in an equal sized space these airflow ports will be right up against your wall. Unless you plan to do some construction to your house to allow for proper airflow intake and ventilation, this is a recipe for failure. Expect to need a square foot of space outside your tent for a ducting system to exit your exhaust port. A 2x3 tent in your 2x4 foot space will suffice, so long as your inlet and exhaust ports are at the side of your tent allowing for proper airflow throughout.
2. What plants (or cannabis strains) are you growing?
Another thing to consider is what kind of plants you will be growing, or alternatively, what strain of cannabis you will be growing. Plant types vary in their height and girth and therefore knowledge of how much space each plant will take up is a necessary component to ensuring you get the right sized tent. If you are growing cannabis, different strains will grow very differently. Some will be short and stout, while others could be very tall and lanky. Once you determine what strain you will be growing do some research to figure out its growth patterns before purchasing a grow tent. Even if you have the space for a large grow, determining this will help ensure the right sized tent so it is easier to control environmental factors within the tent.
3. What kind of yields are you expecting?
Depending on why you are growing, whether it be as a hobby, medicinal cannabis use, or just for occasional recreational use determining how much yield you expect to have at harvest is going to be a large factor in how much plants you will need to grow, and therefore how large a grow tent you will need. The more yields you expect the more plants you will need, and therefore the larger tent you should have. As mentioned in the previous paragraph, what strain you will be growing will also affect how much space you will need per plant. In addition to this, you will need to consider what training styles you will be using. Generally speaking, the more invasive the training, the more yields you will generate - but this also means your plant will take up more space in your tent as a result. This leads us to your next consideration...
4. What training style will you be using?
When growing cannabis it is pretty essential to properly train your plants in order to optimize light and space for the best possible yields at harvest. Some training styles take much more space per plant to properly utilize, so it is important to not only understand the strains typical growing patterns, but also to manage space in advance to prepare for how much room they will need once adult training is in full effect. Growers have plenty of training options, and each have their own benefits and drawbacks depending on what your grow needs are. Low stress training like bend and secure are the basics of plant training and tend to require less space per plant, while a technique like screen of green or “topping” tend to take twice or sometimes three times as much space per plant. A general rule of thumb would be:
Training Style: Plants per square meter
Low Stress: ~4
Screen of Green: ~1
Pruning (Topping, Pinching): ~1
Sea of Green: ~4-16 (depending on vegetative cycle timeline)
As you can see from this breakdown, the space you will need per plant varies drastically depending on the training style you plan to implement. It’s therefore important to plan ahead and consider this before purchasing a grow tent.
5. What kind of lighting will you be using?
You’re probably wondering how your light would affect the decision of what grow tent you should buy. Simply put, the strength and coverage area of your lighting is the most important thing that needs to be considered when growing indoors and to obtain adequate yields that you can be proud of. What you will need to consider is how much money you have to spend on a light, how far the light should be from your plant canopy during the flowering stage, and what the coverage area the light will have at this distance. Most of your money will be spent on a good lighting system for your grow space, so determine what the coverage area is for the light, then buy a tent that matches this. Let’s look at the FourBudz pro3 640 watt light as an example.
This light has optimal power to support bud growth during the flowering stage, though it must be just under 3 feet from plant canopy during this stage, covering about a 2.5-3 square foot area. If the light is placed any higher for a larger coverage area, your yields will begin to suffer. Therefore if you have enough for only one pro3 light, your tent should not be any larger than 3 square feet or the reflective mylar walls will be rendered useless and your yields will suffer heavily.
With these considerations laid out, you are now ready to make a decision on what sized tent you will need to buy for your grow. Your next step is making sure the tent you get has the features of a good tent. There are many out there, and some are notably better than the competition. On the other hand, others can have all the features you need and more, but are overpriced due to brand marketing and other factors. To learn about tent features to look for, my article “9 things to look for when buying a grow tent” will demystify the topic. Be sure to check out my equipment recommendations page as well for a comparison between the top brands on the market in terms of value, price and features.
How to raise or lower humidity levels in your grow tent.
Having issues with humidity in your grow tent? This is a pretty common problem among indoor growers, and there can be some pretty serious consequences for both you and your plants if it is not dealt with. The most common way of dealing with this issue is to install a proper ventilation system with oscillating fans inside the tent to promote airflow. Though before you buy an inline fan and vent system, there you should first educate yourself on why you need it and what equipment to buy so your household does not become plagued with mold and mildew.
What is causing the humidity?
The humidity in your grow tents will rise and fall based on a variety of factors. The reason there is humidity in a tent is mainly the result of a process called ‘transpiration.’ This is the process of water moving through the plant and being naturally expelled as water vapor from the stems, leaves and flowers of the plant.
One of the biggest factors for humidity is how many plants you have growing in your tent. The more the air in your grow tent becomes replaced by plants, the more they act as natural windbreakers, preventing air from fully circulating the tent and cycling in fresh air. The less air movement there is, the more water vapor is trapped in the tent, directly affecting humidity levels.
Why is the humidity level such a big deal?
The humidity level in your grow tent is important for a variety of reasons. Firstly, the high level of humidity can hinder the growth of your plants as it can affect the transpiration rate of your plants, forcing plant metabolic rates to decrease.
Secondly, high levels of humidity and heat in your grow tent is a welcome invitation for mold and mildew that can pose health problems for both yourself and your plants. Plant leaves that are sitting on top of each other collect moisture between them and generate mold and mildew. As well, if the tent is not regularly cleaned mold and mildew can grow almost anywhere, affecting air quality for your plants and your home.
It is important to keep humidity in check for these reasons. Make sure to invest in a hygrometer and place it in your grow tent to keep an eye on this important data. There are basic digital thermometers that have built in hygrometers, so you can invest in one of these and kill two birds with the same stone.
How do you deal with humidity issues in your grow tent?
The typical solution for dealing with humidity levels in your grow tent is to install an inline fan. To help circulate some of the humid dead air inside the tent it is also a good idea to ensure you have some oscillating fans inside the tent as well. Though be sure when you are purchasing a fan to consider a few factors. These include how loud it is, fan speed and airflow, and safety certifications.
Grow tent vents typically have ties that will wrap around a smaller ducting tube, so it is important to get an inline fan that is the same size or smaller than your vent diameter. Typically an inline fan that is 4” in diameter will provide the ventilation that is needed up to a 4x4’ grow tent, depending on how big and hearty the plants are, and how many plants there are in the tent. To invest in a fan larger than this is unnecessary and could actually make more problems for your grow space.
The larger the fan, the more powerful it is. This means more air will be be flowing through your tent, which sounds like a good thing- but too much airflow and humidity levels may not be high enough. Also, the passive air inlets of your tent may not be enough of an opening to fill the void produced by the inline fan, meaning it will be forced to pull air from other air inlets in your tent that do not have a mesh filter preventing dust and other particles from entering the space, such as zipper holes, cable ports and more. Possibly the worst case scenario from this situation is that an inline fan that is too powerful for the size tent you have will create ‘negative air’ in the tent, meaning that air is being pumped out faster than it is coming in, creating a vacuum where the plants are basically being suffocated from lack of air and oxygen. A simple fix for this is to purchase a smaller inline fan and ensure it either comes with, or has a speed controller built in. This will allow you to turn down fan speeds and control airflow and humidity levels with much greater ease.
Ensuring your household does not have to deal with mold and mildew is as easy as keeping a clean grow space and installing a carbon filter and inline fan to keep humidity levels in check.
Another solution for controlling humidity in your grow tent is by using a humidifier/dehumidifier. For the smaller grower I would not recommend this, typically humidity issues can be solved with proper airflow and ventilation management. Although if you plan to grow in a larger space with many plants, this could be a good option for you. The larger the space, the harder it gets to control temperature and humidity, so it is helpful to manage these factors with automated mechanics such as a dehumidifier that will auto adjust humidity levels with the touch of a button.
Now you are ready to purchase an inline fan and carbon filter kit. Make sure it is properly installed to avoid the issues discussed in the previous paragraphs, and visit my product recommendations page for brand comparisons in terms of value, price and features. Good luck, and happy growing!
A common question I get asked is when you are growing in a grow tent, where should you put the thermometer to get an accurate reading?
It is a valid question to ask, because depending on the size of the tent and the type of lighting you are using readings could vary drastically from the top to the bottom of the tent. Things get even more complicated if you are using a thermo hygrometer and want accurate readings of humidity levels as well. You are right to do your research and make sure you are getting accurate readings, as temperature and humidity levels can often be the cause of a list of problems for your plants. This article will address the question of where to place your thermometer, and educate you on typical symptoms your plants exhibit when there is trouble brewing with temperature or humidity levels.
There are a few solutions to the question of where to put your thermometer in your grow tent. The quick and simple answer? Everywhere. But how can temperature vary so much in such a small space? It really does depend on what you are growing, how much of it you’re growing per square meter, the type of lighting you’re using and the quality of ventilation and airflow you have. All of these factors play a part in your grow environment, and all of them can change temperature levels significantly. Let me explain.
For instance, if you are using an HID light in your grow tent, this type of lighting emits a large amount of heat. Left unattended this heat would sit at the top of the tent, and slowly creep down to your plants the longer it says on. Installing a proper inline fan and ventilation system helps to dispel this stale hot air, but it does not mean heat is not being generated and emitted regularly by the light. Placing a thermometer too close to this light will throw off temperature readings as it would likely be much hotter an inch from the light than it would be at the bottom of the tent. Alternatively, placing your thermometer at the bottom of the tent will not necessarily give an accurate reading of temperature near the plant canopy.
So how to solve this conundrum? Solution 1 is to simply purchase 2-3 cheap thermometers or thermo hygrometers and place them at height specific intervals throughout the tent to get an idea of temperature and humidity at the plants roots, base, and canopy. Another more temporary solution is to rotate where you place the thermometer in the tent on a daily or bi-daily basis. This should give you a fairly accurate reading so long as external factors around the tent are not affecting readings too much. This means that outside or household humidity and temperature levels are not fluctuating by too much when moving the thermometer to the next location.
If you choose to rotate your thermometers location, or even if you took the safe route and purchased several thermometers, be sure to keep a look out for temperature and humidity related symptoms with your plants. When growing cannabis a typical sign of under temperate conditions is when plant leaves begin to darken significantly and even turn purple in colour. Conditions that are too cold and you will be lucky if the plant survives the night. If it is too hot on the other hand, and your plants leaves will begin to fold in half.
While an environment that is too hot will not directly lead to plant death, it does weaken the plant and delay growth, which opens the door to other problems such as pests, mold or the leaves being burnt. Other symptoms that are a bit more general, but could be related to temperature include leaf edges looking burnt or turning brown, curling leaf edges, wilting or drooping leaves, or the entire plant looks to be wilting or drooping.
So it’s therefore important to regularly check the temperature and humidity of your grow space. Having a few strategically placed thermo hygrometers will help to identify any issues with your grow environment and help you address them before they become an issue for your plant. Now you’re ready to take on your grow environment with this added knowledge. Get what equipment you need, and start growing! Check out my equipment recommendations page, or click here to see what the best value equipment on the market is and where to find it.
'Prof' is a professionally trained Canadian teacher with a love of horticulture and advocate of the democratization of cannabis cultivation, especially for medicinal purposes.