Anyone can grow marijuana–its nickname is "weed," after all–but actually growing it well requires knowledge, patience, and finesse. There’s a lot to learn Marijuana: The truth about growing your own pot Nick Hice, cultivation facility manager at Denver Relief, harvests several of the plants, getting them ready for the drying process. Kayvan
10 Things Nobody Tells You About Growing Marijuana
Anyone can grow marijuana–its nickname is “weed,” after all–but actually growing it well requires knowledge, patience, and finesse.
There’s a lot to learn about growing marijuana. For starters, the so-called weed called Cannabis is actually an annual flowering herb, and its medicinal properties have been recognized for centuries (in ancient China therapeutic purposes were known at least 2,000 years ago).
Here are 10 things nobody tells you about growing marijuana:
1. All marijuana is Cannabis but not all Cannabis is marijuana.
Two distinct biotypes of Cannabis sativa are hemp (grown for its fiber) and marijuana (with high concentrations of the chemical THC). The acronym THC is a shorthand way to describe tetrahydrocannabinol, which produces reactions to the human nervous system that range from therapeutic to hallucinatory. (Both biotypes contain the chemical CBD–see below.)
For decades, both hemp and marijuana were illegal to grow in the US. The passage of last year’s Agricultural Improvement Act of 2018 (signed into law by President Trump in December) legalized production of industrial hemp. The legality of growing marijuana varies from state to state.
2. There’s reason for all the fuss about CBD and Cannabis.
Like THC, CBD is a compound found in Cannabis plants. Unlike THC, CBD does not get you high.
In recent months CBD, a shorthand way to describe the chemical cannabidiol, has become a popular ingredient in everything from cosmetics to detox drinks. Its proponents tout its ability to relieve everything from inflammation to anxiety. With research to test its efficacy in various dosages, CBD has been approved by the FDA to treat epilepsy, to relieve chemotherapy side effects (including nausea), and to counteract weight loss and lack of appetite for people with AIDs.
3. The number of marijuana plants you can legally grow varies depending on where you live.
Above: Read more about the fate of this tiny marijuana seedling in The Marijuana Plant and Me: Part 1.
State law varies when it comes to the legal amount of marijuana you can grow. For instance, in Alaska you can grow up to 12 plants in a household of at least two adults who are older than 21. In Colorado, the limit is six plants. In Washington, you can only grow backyard marijuana for a medical use. In Alabama, possession is a felony for repeat offenders.
4. Growing marijuana is a lot of work.
Above: Cannabis grows in a hoop house in Humboldt county, California. Photograph by Brian Shamblen via Flickr.
You can grow Cannabis indoors or outdoors. (If outdoors, choose a variety that grows well in the garden, such as Honey Cream, Speedy Chile, or Critical Kush.) Either way, if you want to maximize your marijuana harvest, the plant will need optimal growing conditions including the right amount of sunlight, water, and fertilizer.
For one thing, marijuana plants need 12 hours a day of light and 12 of day to flower (which is how they produce THC and CBD. For this reason, many growers prefer to cultivate them indoors using grow lights to regulate the cycle.
If humidity levels are too high, plants can develop bud rot (humidity levels below 50 percent are essential).
Only female plants produce flowers with high cannabinoid levels, so you need to know how to tell the difference between male and female plants.
5. The way to tell the difference between male and female plants is by the buds.
Female plants exhibit bracts with pistils which grow in the nodes between stem and leaf.
6. Hemp requires different growing conditions from marijuana.
Hemp grows outdoors, but you can grow marijuana outdoors or indoors (with the use of plant grow lights).
7. It can take up to six months for a marijuana plant to reach maturity.
From seed to maturity, a marijuana plant’s rate of growth can vary great depending on the variety. Seeds typically germinate in from three to seven days. After germination, the period from seedling to the beginning of flower production can last from two to three months. (Hemp thatis grown for fiber is harvested before it flowers.) After flowers appear, a plant can be harvested in from six weeks to four months, depending on variety. (Indica varieties typically mature faster.)
8. Cannabis belongs in the back of the border in a garden.
Reaching heights of up to 13 feet Cannabis plants can steal the limelight from the rest of the garden. Take the focus off Cannabis by planting it in the back of a border.
9. It’s easy to tell when Cannabis plants are ready to harvest.
“You’re in the weed harvest window when most of the pistils have darkened and curled in,” notes Grow Weed Easy, which offers a photo gallery to illustrate.
10. You can make CBD oil at home.
To make CBD oil at home, you’ll need finely ground marijuana, a carrier oil (such as coconut oil), a double boiler, cheesecloth, and tongs. See step-by-step instructions at Key to Cannabis.
See more growing tips at Marijuana: A Guide to Planting, Care & Design in our curated guides to Herbs 101. Read more:
Marijuana: The truth about growing your own pot
Nick Hice, cultivation facility manager at Denver Relief, harvests several of the plants, getting them ready for the drying process. Kayvan Khalatbari, owner of the pot-growing business and dispensary, talks about growing your own marijuana.
DENVER, CO. – FEBRUARY 04: Dan Ericson trims the sugar leaf off the bud readying it for the drying process. Kayvan Khalatbari owns Denver Relief, a marijuana growing, dispensary, and consulting business. Khalatbari and his employees are meticulous in their marijuana cultivation from start to finish and says the process takes constant care and vigilance by anyone considering growing the plant. (Photo By Kathryn Scott Osler/The Denver Post)
Dozens of medicinal-marijuana plants grow under special lighting at Denver Relief. Photos by Kathryn Scott Osler, The Denver Post
Kayvan Khalatbari is operations head of Denver Relief, a marijuana-growing dispensary and consulting business, where every plant is tracked througout its growing life.
Dan Ericson trims the “sugar leaves” — the single leaves close to the bud — off a pot plant, readying it for the drying process. Then he’ll hang the plant upside down for a week to dry.
So you want to grow pot. Or you’re worried the neighbors will.
Marijuana is the botanical conversation piece that just won’t go away. Reactions to it run a wild gamut: It’s the evil weed or a source of future state tax revenue and entrepreneurial ingenuity. Or it’s the only path left to freedom from pain for some people, and journalists should write about it with the same seriousness that they accord blood-pressure medicine.
If you’re 21 or older, Amendment 64 allows you to cultivate up to six marijuana plants in an “enclosed, locked space” in Colorado. (This is still illegal under federal law.)
Sounds simple. But growing marijuana isn’t easy, those who do it professionally say.
Until 2014, it’s illegal to sell plants to those without a medical-marijuana card.
Growing cannabis from seed is possible but impractical.
Such activities are subject to federal prosecution.
One thing is certain: Legalization is changing the landscape of our state. Maybe not our yards, but surely our headspace, our parties, our neighborhoods and our lives. If we understand the plant, it will help us talk about that change using facts rather than fear or naive enthusiasm.
We went to experts with the questions we felt any gardener and homeowner would have. Our interviewees for this story and video were Kayvan Khalatbari and Nick Hice, co-owners of Denver Relief, a medicinal-marijuana dispensary whose growing facility is home to about 1,900 marijuana plants.
An overview of the basics
Question: Where can Coloradans grow marijuana plants? Can people just stick them in a sunny window next to basil and aloe?
Answer: A big thing to remember with marijuana plants is that they need to flower to produce THC ( tetrahydrocannabinol, the chemical that gets people high) and other medicinal cannabinoids. In order to do that, they need 12 hours of light and 12 hours of total darkness a day.
So the best place to grow marijuana is in a room in the basement with a locked door so light doesn’t inadvertently get in when the plants are “sleeping.” If you don’t have a basement, a small closet with light-leak protection around the door will work.
A: All sorts of prepackaged items are available, like grow boxes or grow tents, that are probably best for a small space like a closet, or fo r someone who doesn’t want to get into growing marijuana too intensely.
But if you’re trying to get six plants to be as robust as possible, you probably need to install something that’s more permanent, like a 400- to 600-watt lamp with a hood assembly that comes with a ballast, which you place at least a forearm’s length above the plants.
Keep in mind that the ballast is going to get very hot, so you need to have adequate cooling in the room as well, like a portable air conditioner with a thermostat. You don’t want the room to get above 80 degrees because the hotter it is, the slower the plants grow. The ideal temperature is 75 to 80 degrees when the lights are on and 68 to 74 degrees when the lights are off.
You also have to watch humidity, because every time you water plants in a small space, you’re going to get high humidity. It should be below 50 percent to prevent bud mold or rot.
You can measure humidity with a hygrometer from a hardware or grow store, and reduce it with a dehumidifier or air conditioner.
Q:How would a home grower comply with the rule that limits them to three plants in flower?
A: That means you can grow only three plants if you don’t have two separate growing areas. The reason having only three plants is bad is that you want to keep a rotation going. Or else every time you get done harvesting, you have to go back to a store. If you want a continual supply, you want the perpetualness of having a vegetative stage and a flowering stage going all the time.
Logistics and costs
Q: How much does all this stuff cost?
A: Most grow boxes are $200 to $400, but if you want one with HVAC temperature-control capabilities, it’s pretty pricey — close to $1,000. You can find grow boxes at most local hydroponic stores or grow shops.
A light system and building materials will run $350 to $1,000, and electricity costs per harvest are $100 to $200.
Q:Where would a home grower get seeds?
A: I actually never recommend starting a marijuana plant from seed, because you have to determine whether the seeds are male or female, which is difficult. Only female plants produce the flowers that are most desirable in terms of cannabinoid content. Male plants are pretty much unusable (for smoking purposes).
The best thing to do is to buy a clone — a cutting from a proven plant. People who have red cards (medical-marijuana cards) can buy clones from medical-marijuana centers and grow their own plants. If you know somebody who grows, it is legal today (under state law) for a 21-year-old (or someone older) with a marijuana plant in Colorado to give another 21-year-old (or older) a clone from that plant. But if you don’t know someone who grows, I don’t see an option to legally purchase seeds or clones in this state before 2014, when retail marijuana facilities open.
Cannabis botany 101
Q:Tell us about the different strains of marijuana. How would people choose one?
A: There are three types of cannabis — indica, sativa and ruderalis.
Ruderalis is a ditch weed found in Europe with low THC content. The marijuana we’re familiar with is indica and sativa. Indica has higher CBN (a type of cannabinoid) content, which relieves pain and makes you lethargic. Sativa has the highest psychoactive content, is energizing and provides lucid thought. Most everything available today is a hybrid (and) carries the characteristics of both indica and sativa.
Indica-dominant hybrids are good for growing indoors, because they only get 2 to 3 feet tall from the top of the pot, with a diameter of 12 to 18 inches.
Q:Isn’t hemp a type of marijuana? Can that be grown in a house?
A: Hemp is basically a cultivated variety of sativa. For several thousand years, it has been bred for tall growth, fibrous stems and low THC levels. It still has the medicinal cannabinoids, but you need so many hemp plants to get valuable cannabinoid content — more than 100 — that it wouldn’t be worth growing at home.
Care, air and food
Q:What’s next after obtaining clone plants?
A: Place the clone in a pot filled with a planting medium. Although potting soil would technically work, we use a soilless growing media made from coco fiber, worm casings, perlite and vermiculite because it’s developed specially for marijuana, even though (manufacturers) don’t admit that. You can get premixed versions at grow stores — Royal Gold Tupur is a good brand.
A lot of people use hydroponics, where plant roots are free flowing in what is essentially a circulating water bath. But that can be a problem for inexperienced growers, because if you accidentally add too many nutrients to the water, you can burn or kill the plants because the roots suck the extra nutrients right up. Soilless media act as a buffer to protect the roots.
Q:What type of container is used?
A: Many people use 5-gallon plastic buckets, but those create problems because the roots just wrap around themselves and form a large root ball. If you use a 3- to 5-gallon fiber pot, the root sticks through the pot and (the plant) air-prunes itself, while feeder roots grow in the pot. That gives the plant a larger nutrient intake.
Q:How are the plants fed and watered?
A: Most nutrient products in hydroponic stores come with very easy-to-understand directions and a “recipe” and schedule on the side of the package that you can follow. You should also water the plants every two to three days with tap water that has sat in a container for 24 hours to let the chlorine evaporate.
In addition, because you aren’t growing the plants outside where carbon dioxide is abundant, you must supplement the indoor air with it. Many small-time growers use CO2 tanks (similar to those on a soda fountain machine) with a regulator valve. You can get these tanks from grow stores or beverage suppliers. You can also buy automatic controllers for the tanks that release CO2 at the ideal ratio of 1,250 to 1,550 parts per million.
Getting to harvest
Q:What gets done with the plants after they’ve been potted?
A: Start with clones that are 4 to 5 inches tall, and give them 24-hour light until they reach 9 to 15 inches. If you keep temperatures below 80 degrees, this takes four to five weeks — less if you’re growing hydroponically.
Then you want to throw the plants into the flower cycle (12 hours of light followed by 12 hours of dark). During the second to third week of flowering, prune the bottom third of the plant so it puts its growth energy into the top once buds form.
A: Most plants are ready to harvest after 65 to 70 days of flowering. A good way to tell if the plant is harvestable is to get a 45x magnifying glass from a grow store and check out the trichomes on the flowers. Trichomes are the translucent resin glands that contain the cannabinoids. When they turn amber or a milky purple, you know they’re ready. This sounds difficult, but it’s actually pretty easy for the layman to do.
Another option is, if about 80 percent of the flower’s pistils turn orange or darker brown rather than white, then they’re ready to harvest.
Processing the harvest
Q:OK, say a home grower successfully gets three pot plants to the final flowering stage. They’re healthy and producing buds. How are they processed?
A: When a plant is fully mature, some people cut it off at the base, then cut off the fan leaves and hang it upside down. After it’s dried, they’ll trim off all the outer “sugar” leaves (the single leaves close to the bud).
What we think is best is to take down the plant and cut off all the leaves at once. If you leave the sugar leaves on, they may make the marijuana harsher. We trim so the (flower) bud has a clean egg shape, and use (the sugar leaves) to make concentrates to smoke, vaporize or cook with.
Then you hang the plant upside down for about a week, until the stem snaps rather than bends. Conditions should be about 68 degrees with 50 percent humidity. If the plant dries too fast, it locks in the chlorophyll, making it taste like plant material instead of marijuana. If it gets too humid, it can mold.
More questions, more answers
Q:Where can people find legitimate, affordable pot-growing help?
A: There’s a 1,200-page book that is beyond most other books and pretty much says everything you need to know about marijuana growing: “Marijuana Horticulture: The Indoor/Outdoor Medical Grower’s Bible,” by Jorge Cervantes (Van Patten Publishing, 2006). Our guys still keep it on hand, and they’ve been growing for 15 years.
Q: Can THC be topically absorbed? Could people who grow fail a drug test if they touch their plants?
A: You shouldn’t have any issue with handling the plant, but the scent is very pronounced, so you may smell like marijuana.
Q:What are the dangers for those who grow?
A: Be discreet. You wouldn’t tell everybody you have $2,000 just sitting on your nightstand, so don’t tell everyone you have $500 to $1,000 worth of marijuana in your basement. Putting a lock on your growing-room door and installing a home security system is not a bad idea.
Q: This is not something somebody who’s not fully committed should do, is it?
A: It is a daily, daily beast to take care of these plants. If you don’t acknowledge something it’s asking for for a day or two, you can lose two weeks of growth. Even if you do not mess up, that doesn’t mean you’re going to grow good marijuana.
Edited from an interview with Kayvan Khalatbari, principal of Denver Relief Consulting.