Light: 2,200k. “For a closet set up, I would recommend a 175-watt HPS light,” Lipton said. “Some people try to use fluorescent lighting, but I wouldn’t recommend that. You’re just not going to get a very good outcome. Nowadays, HPS lights can just go right into your home outlet, and you’d just need a timer [to set the intervals]. Position the light directly overhead. They can be pretty powerful, so you’re going to want it at least two feet from the top of the canopy [to prevent the plant from overheating].”
Another layer to consider is that cannabis cultivation must happen “out of plain sight.” “You can’t have any odor. If it’s offending people in the neighborhood, then it’s an issue.”
“Growing cannabis in tight spaces is not my usual recommendation,” said Stephen Lipton, the cultivation manager at The Farm Recreational Marijuana Dispensary, an award-winning recreational facility in Boulder, Colorado, specializing in what it calls “craft cannabis.” At any given time, Lipton oversees close to 15,000 plants across seven different facilities in Boulder County. “If you have a really tight space and it gets too hot or too humid, you’re going to have big trouble.”
Plant and maintain the vegetative cycle until the plant is mature.
Though the 12-hour interval is fairly universal, knowing exactly when to induce flowering is less clear. For the home grower, it usually comes down to space; the longer one waits to trigger the flowering cycle, the taller their plant will be. A good rule of thumb: cannabis will only continue to grow 30 to 50 percent once the light source is reduced. If the plant is growing in a closet, growers should trigger the flowering cycle, understanding that there must be more than two feet of space between the canopy of the plant throughout the entirety of its life.
pH of Water: 6.3 to 6.7. “You’ll need a meter that you can stick into your water and tell you the pH,” Lipton said. “You want something between 6.3 to 6.7 pH for watering your plants. That sounds like pretty sophisticated stuff but it’s really not. A lot of times your tap water will be 7.8. You can use what they call pH down. That’s a crucial step.”
Foster the right growing environment.
Relative humidity: 30 to 45 percent. “If you live somewhere humid, you’re probably going to want to buy a dehumidifier,” said Lipton. “In Boulder, we sometimes have to add humidity.” At home, that can be done with a reliable humidifier.
Sticking to that schedule is key, he added. “Say you’re at day 30 of the flowering cycle and you come into that closet when it’s supposed to be dark and turn a bunch of lights on. You’re going to throw the whole cycle off and that’s the end of that. It only takes 10 seconds.”
Cannabis, like all plants, prefers certain environmental conditions in order to thrive. Temperature, humidity, light intensity, and airflow are all factors that will need to be monitored and regulated in order to keep cannabis healthy through its different phases.
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Weed plants need different amounts of light during their vegetative and flowering stages. You don’t have to worry about this in an outdoor setting—the sun and the season dictate this—but when growing indoors, you will be controlling it.
The flowering stage will always take about eight weeks—some strains take seven, some nine, some even more, it depends on the strain.