Because the amount of light a plant receives is so important, you’ll need to make your indoor grow space light-tight. Light leaks during dark periods will confuse your plants and can cause them to produce male flowers or revert to a different stage.
The first step in odor control is making sure temperature and humidity are under control in your grow space—high temperature and humidity will perpetuate odors.
Check temperature and humidity levels
There should be a comfortable airflow both above and below the canopy, and fans shouldn’t blow air directly onto plants—this can cause wind burn, which makes leaves recede into a claw-like deformation.
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.”
Cannabis plants yield the highest-quality (and quantity) flowers after maturing. This usually takes about a month to happen. “I recommend planting in a five-gallon Home Depot bucket,” Lipton said. “It’s really important to have proper drainage, so you want to drill some holes in the bottom. The biggest mistake people make is that they overwater and suffocate the roots. Cannabis likes to be watered and dried out before it’s watered again.” During the vegetative cycle, the plant should be exposed to a minimum of 18 hours of light. Remember to open the closet door while the lights are on to prevent the space from heading north of 78 degrees Fahrenheit.
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.
Plant and maintain the vegetative cycle until the plant is mature.
To understand the flowering cycle, it’s important to remember that cannabis is a plant. And, like most plants, it follows the seasons. To trigger flowering — which will take 55 to 60 days to complete — growers reduce the time plants spend exposed to the light source from 18 hours to 12. “You’re basically telling your plant it’s mid-September,” Lipton said.
Despite the hurdles, many first-time growers still choose to cultivate cannabis indoors (which is legal in Alaska, Colorado, Washington D.C. and Oregon), and there are steps to maximize a plant’s chances of succeeding. It all starts with a plant’s genetics. “For your typical closet setup, you’re going to want a plant that stays short,” Lipton said. “A lot of time that means an indica. Sativas are really tall and lanky.” (More on the difference between those two families here.)
Trigger the flowering cycle.
The last step involves curing the bud. “Curing is just as important as the growing process,” Lipton added. “We do a slow cure, which means that it takes anywhere from three to six weeks depending on variety.” Temperature and humidity play a large role during cure and must be maintained to ensure a great final product. “Our actual cure process is somewhat of a secret, so I cannot share the fine details,” Lipton said. “But it’s an art form and extremely crucial to our success.” The reason growers cure bud after harvesting is that it creates a smoother smoke and increases its potency. Detailed recommendations for proper curing can be found online, here and here.
“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.”