The Elevated Agriculturalist: Beyond CannaPorn – Growing Cannabis Indoors
Indoor growing is my favorite way to grow cannabis, because I get to control everything. Not that I’m some sort of control freak, but I’ve had too many things go wrong growing outdoors. Things like hail, rain, wind, drought, animals, pests and disease are all threats to your cannabis crop. All these factors are much easier to manage indoors.
There is so much to cover with the indoor grow – even just touching on all of the different aspects in this space proved difficult. When I need to look something up or check on a method I’m using, I inevitably turn to these two resource: Cannabis Encyclopedia by Jorge Cervantes, and The Cannabis Grow Bible by Greg Green. These two books, along with Green’s Cannabis Breeders Bible are a constant source of information about how best to cultivate the cannabis plant. Both provide information in an easy-to-understand format, and are loaded with helpful images that aren’t just CannaPorn.
Now that you’ve made the decision to grow indoors and you have these two books on order, let’s explore the myriad of methods used in indoor growing and find the one that best fits your situation. Even though indoor growing is designed to gentrify the cultivation process, there are so many different variables involved, that every grow I’ve ever been involved with has had many differences. So, rather than tell you the ideal way to set up your grow, I want to give you the information you need so you can decide which methods and equipment will work best for your space and your situation.
Like outdoor cannabis cultivators, the indoor grower is faced with several questions at the outset that will go far in dictating how things are done moving forward. You’ll need to consider location, lighting, water quality and accessibility, electrical demands, heating/cooling, ventilation, odor control, and any auxiliary environmental controls you may want to deploy. And that’s all before you decide which technique you are going to use, your grow medium, nutrient recipe, and of course, cultivar selection.
Before legalization, the number one concern you had was security. Now that we can have legal grow rooms, your biggest question will be ease of use.
The location of your grow room is critical to your success. Before legalization, the number one concern you had was security. Now that we can have legal grow rooms, your biggest question will be ease of use: how easy is it for you to access the room and get plants/ soil/ waste in and out? How easy is it to get your electric and water hooked up? How difficult will it be to get fresh air into the room? How are you going to get the stagnant, odor filled air scrubbed and out of the room? All of these factors should be considered when deciding where to locate your grow.
Size is also something that you’ll want to take into account when selecting your site. If allowed, Cannabis plants can grow large – 10’+ indoors. So as a general rule, you’ll want 3’-4’ square per plant with at least 8 feet of vertical height. For two plants 10’ square is quite sufficient. These dimensions will give you room to maneuver around and tend to your plants, while still having them staked out so they are getting maximum light exposure.
Plants needs light on different parts of the spectrum at different stages of their growth.
After location, light selection is the most expensive and critical of choices. Lights come in many different types and sizes, so it’s important to do some research and decide which set up will work best for you. Plants needs light on different parts of the spectrum at different stages of their growth. While in the vegetative stage, they like their light in the 400nm, or blue range. When flowering, they like the light in the orange/red range, 700nm. You can either set up two separate areas, or switch out your lights when you induce flowering.
There are also two main types of flowering lights: High Intensity Discharge (HID) and Light Emitting Diode (LED). HID lighting is most common and offers more penetration of the canopy, while LED lights are designed to save on costs while still providing the right spectrum of light. Regardless of which lights you choose, you want to make sure you have sufficient light coverage of your space. According to the Cannabis Grow Bible, you want no less than 45,000 lumens beaming down on your plants.
An often overlooked factor in watering is temperature – you want the water in your nutrient solution to be at room temperature.
Water is your next biggest decision. I always test my water to see what I’m working with, considering mineral content and Ph. A nutrient wand and a digital Ph meter are all you need to make sure your water quality is acceptable. Another factor to consider is how you are going to get your water into your grow room. An often overlooked factor in watering is temperature – you want the water in your nutrient solution to be at room temperature. A good practice to cultivate is to fill your reservoir the night before, add nutrients and oxygen, and let it come to temperature. We’ll be talking much more about water in a future article.
Humidity is the measure of moisture that’s in the air, and is controlled by using a dehumidifier. This is important because of something called “vapor pressure deficit.” Simply put, plants use water as a vehicle for nutrients. Their roots absorb nutrient-laden water and carry it through out the plant. After the plant is finished extracting the nutrients from the water, the remaining water is released via a process called transpiration. When the air surrounding the plants is humid, there not much room for the water to escape out into the air. When the humidity is low, there is ample space for the water to flow to and the vapor pressure deficit actually acts as a magnet for the water.
You want fresh cool air entering your grow room, so you’ll want to source it from the outside if at all possible.
Air movement also needs to be considered, both the air moving into the space and the air as it is being discharged. You want fresh cool air entering your grow room, so you’ll want to source it from the outside if at all possible. Once you coax the air into the space, you want to disperse that air as evenly as possible, remembering the lower portions of the grow room as well. Horizontal Air Flow (HAF) fans are designed for this purpose, mount to the wall, and offer diverse flow patterns to assist you here. The air in the room is bonding with the terpenes and thiols that are being released from the plant. This gives your air a scent, which in most states you need to eliminate before you send it back outside. We use large charcoal filters and an exhaust fan to scrub the air before discharging. One thing to remember about air flow in and out is that you want the amount of air you are bringing in to be about equal to the amount you’re discharging. Too far in either direction will give you a positive or negative pressure situation.
One of the biggest contributors of heat to an indoor grow room comes from the lights.
Temperature control, too, is critical to a successful indoor grow. You want to maintain your room between 65-80 degrees. To accomplish this in an efficient manner we use a mini split which is a heater and air conditioner in one unit. They’re quite efficient and effective. Ours maintains our flower room (700 square feet) for a cost of about $1 day. One of the biggest contributors of heat to an indoor grow room comes from the lights. HID lights can often be linked by ducting, and much of that heat discharged as it’s generated with an exhaust fan. LED lights often have a water cooling system running through them to reduce the amount of heat that is given off.
Finally, ENS control is the light timers which range from a grounded dial timer through to a programable touchpad that can be operated remotely. The system I use has my lights turn on at 25%, intensifying up to 100% over twenty minutes. I also like to spike them to 120% during the middle three hours of their day.
The final set up decision you need to make is weather you’re going to grow in soil or hydro.
As you can see there are pros and cons to both. I’ve used both setups with great success. I like hydro for my larger grows, because aside from the nutrient monitoring, the system is heavily automated and allows me more time to tend to my plants without spending time feeding, watering etc. I like to use soil for my personal plants because of the plants’ ability to work symbiotically with the world of microorganisms that live in our soil. This relationship allows for a terroir to develop – a local taste of place flavor, if you will.
Here is my starter soil recipe which I then add amendments to as the plants dictates.
- Pro Mix 4 cubic yards
- Perlite; 1 cubic yards
- Green Sand 5lbs
- Dolomitic Lime 2lbs
- Worm Castings 2lbs
To summarize, cannabis cultivators can pursue plenty of ways to grow indoors, and as you learn more, you’ll develop a method that works best for you. There’s lots of trial and error involved, but I hope the above recommendations will go a long way in helping you build an indoor grow room that is easy to use and successful.
Vapour-Pressure Deficit: The difference (deficit) between the amount of moisture in the air and how much moisture the air can hold when it is saturated.
Lumen: A measure of the total quantity of visible light emitted by a source.
Transpiration: The process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers. Water is necessary for plants but only a small amount of water taken up by the roots is used for growth and metabolism. The remaining 97-99.5% is lost by transpiration and guttation.