I was never very good at math in school, but as a marijuana grower, I’ve had to get better at it.
In fact, math skills are essential for cannabis growers, especially if you’re running an indoor marijuana grow room.
The first thing I do when I consider a room or other enclosed space for indoor growing is to measure the square feet and the cubic feet of the potential grow op.
These are crucial measurements.
You must know the cubic feet of your grow op so you can buy an exhaust fan capable of sucking the air out of your room and bringing fresh air back in.
You need an exhaust fan that can move the entire volume of air out of your marijuana grow room every five minutes.
Exhaust fans are rated by cubic feet of air per minute (CFM).
The square footage of your grow room is crucially important when you’re choosing your hydroponics grow lights and otherwise configuring your space.
This includes how many marijuana plants you can fit into your room.
The generic rule is you want at least 35-40 watts of light for every square foot of plant space.
This rule isn’t absolutely rigid because it’s affected by other factors.
For example, the type of bulb and reflector greatly impact how much light reaches your cannabis plants.
In many situations, a 1000-watt high intensity discharge grow light will only give you about 15-20 square feet of useful light intensity and photosynthetically active radiation.
Your calculations become even more complex because you must anticipate the number of marijuana plants you’re growing, and the diameter and height of your marijuana plants when they’re in bloom phase.
This data influences your entire grow season.
For example, if you have a grow space with eight foot ceilings, your calculations include the anticipated mature height of your plants, and the vertical space needed between the top of your plants and the bottom of your light reflector.
In a garden using 1000-watt lights and appropriate reflectors, you lose between 18-45 inches of vertical space because of the reflector depth, reflector hangers, and the amount of distance you have to keep the reflector away from the plants because of the potential for heat damage.
In a room with 8-foot ceilings, you have a maximum total of 94-96 inches top to bottom.
If you have a need for 35 inches total for your lights and light distance, you can’t let your marijuana plants grow taller than 61 inches tall.
This height limitation absolutely determines when in your season you flip your plants into flowering.
Knowing that many marijuana varieties stretch to double their height during bloom phase, you want to flip your plants into 12-12 light cycle when they get to be no taller than 30-35 inches.
By the time those plants get done with bloom phase, they’re likely to be at or near 60 inches tall.
Many marijuana growers don’t do the math correctly, and end up with too-tall plants that grow too close to their grow lights.
When cannabis plants get too close to grow lights, they get burned, and even if they don’t get burned, excess heat creates airy buds.
Or, they don’t receive adequate watts per square foot, along with inadequate light footprint, because they have too much height so light can’t reach up and down the plants.
This means your marijuana plants don’t get enough light and light penetration, which limits yield.
Remedies for this miscalculation include putting your hydroponics grow lights on a light mover (to reduce heat), using air-cooled lights, amping up your air conditioner to keep the plant canopy cooler, bending your plants horizontal so they lose height, etc.
So you see that math measurements and math skills are indeed essential for marijuana growers.
As you plan an indoor growing operation, take careful measurements of the height, width, and depth of your grow rooms.
Estimate the number and size of your marijuana plants in bloom phase.
Calculate the amount of lighting your plants will need to cover the square footage your marijuana plants will occupy.
Also calculate the load-handling mathematics of your electricity supply.
Most regular home room electricity outlets are on a 15-amp circuit that can safely handle only one 1000-watt light per outlet, and not much more.
If you’re running even a couple of thousand-watt lights, you’ll need at least two different 15-amp circuits, especially if you’re also running vent fans, oscillating fans, scrubbers, and other hydroponics growing equipment.
I use online calculators and other online tools that do my math for me, but the essential tactic is to take measurements and do planning before you put plants in marijuana grow rooms.
When you do the math correctly, the result is more and better buds from your marijuana grow rooms.