A growing number of experts are making a business out of teaching people how to grow their own pot. Here's what to know to get started. Knowing how to care for your cannabis plants at each of the four distinctive stages of their life cycle will provide a healthy, productive garden.
As marijuana is legalized in more places, here’s how to grow your own
When it comes to growing his own marijuana, Chris Haynie leaves little to chance.
Inside a grow room in Richmond, Haynie has erected a 42-square-foot tent that houses four marijuana plants, the state’s legal limit for personal cultivation. Haynie’s setup is high-tech: An irrigation system releases moisture on a precise schedule; a motorized LED light timed to mimic the rising and setting of the sun moves along a rail across the top of the tent; and a monitoring system tracks key metrics of plant health, such as the moisture level and pH of the soil, and relays the data to an app on Haynie’s phone. If the system senses urgent problems, he’ll receive a warning text. Haynie’s friends are used to him bolting from a room mid-conversation to tend to his plants.
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Haynie, a bearded 38-year-old cannabis connoisseur who tattooed his thumbs with green ink, is no horticulture amateur. As the co-founder of Richmond’s Happy Trees Agricultural Supply, he’s part of a growing number of experts who are making a business out of teaching people how to grow their own pot. Recent laws in Virginia allow for limited cultivation of marijuana for personal use, and Happy Trees, which Haynie launched in 2019 with Josiah Ickes, 36, specializes in setting up growers to cultivate the plant.
Marijuana remains illegal on a federal level, but many states have abolished restrictions, creating a patchwork of rules throughout the country. Eighteen states and the District of Columbia have passed laws allowing recreational use. Virginia legalized home cultivation in July 2021; under the law, people 21 and older may possess up to an ounce of marijuana. It remains illegal, though, to buy or sell it in any form — including seeds — until 2024, when retail sales are expected to begin.
People still find ways to access seeds. When D.C. legalized the possession of limited amounts of marijuana in 2015, the District lacked the authority to create a legal economic market for sales. So cannabis activists organized seed giveaways throughout the city. At one early event in 2015, lines stretched for blocks.
The regulatory scheme also established what has become an expansive “giveaway market,” in which Washingtonians have used a loophole to provide harvested marijuana as a gift in exchange for the purchase of a legal product. Companies sell cookies, tea or paintings with a baggie of “free” marijuana on the side. One company sells motivational speeches delivered by a person who travels by bicycle.
From Seed to Harvest: The Life Cycle of Cannabis
Knowing how to care for your cannabis plants at each of the four distinctive stages of their life cycle will provide a solid baseline of knowledge and healthy, productive gardens.
It can take four to eight months to grow a cannabis plant. During this time, it goes through four distinct stages: germination, seedling, vegetative, and flowering. It is essential for cannabis growers to understand each stage in the life cycle so they can properly care for their plants. Each phase requires different nutrients, hours of light, and type of light. There are also different tasks that can help make each stage more successful.
It all begins with a seed. If stored in cool, dark conditions, a cannabis seed can remain viable for years. The best seeds are hard and dry and will be light to dark brown in color. Underdeveloped seeds tend to be soft and either white or green. It’s very unlikely these seeds will germinate.
The seed lies dormant until it is exposed to warmth and moisture. You can germinate your seeds by planting them in a moistened seedling starter mix, covered with plastic and placed on a heat mat. It is important to use a seed-starting mix instead of potting soil.
There is enough nutrition in a seed to feed a sprout for about two to three weeks. Any additional fertilizer can burn your plants at this tender age. Once planted, a seed can take five to 10 days to sprout.
Once your seeds have sprouted, the two seedling leaves will be the first to appear. Place a fluorescent grow light about two inches from the top of your plants for 18 hours per day. You don’t need a powerful light for them in the beginning. When the true leaves appear, your little plants can officially be considered a seedling.
The seedling stage of a cannabis plant can last three to six weeks.
The seedling stage of cannabis plant lasts three to six weeks, depending on environmental factors and the strain you’re growing.
During this time, your seedlings are focusing their energy on growing roots and foliage. Because the roots are so small, be careful not to overfeed or overwater. Use a fertilizer high in nitrogen and be sure to dilute it so you don’t harm your plants.
Fluorescent lights still work well at this point. Set your timer so the lights are on for 18 hours and off for six.
Seedlings are susceptible to pests and disease at this age, so this is a good time to apply a preventative neem oil treatment. It’s much easier to prevent spider mites and powdery mildew than to treat them while your plants are so young. If they do get infested or infected at this age, the stress on your plants will likely produce a smaller harvest down the line.
The vegetative stage of a cannabis plant can last one to four months.
After a few weeks as seedlings, your cannabis plants will outgrow their starter pots and start demanding more food and light. The roots and foliage grow rapidly during this stage, which allows the plant to take in more nutrients and carbon dioxide. Don’t be surprised if your plant shoots up two inches in one day!
If you don’t already know, this is when you’ll be able to identify whether you are growing an indica or sativa. Indicas tend to be short and bushy, while sativas are lanky with less foliage.
You will also be able to identify the sex of your plants. About four weeks into the veg cycle, pre-flowers start to appear. By six weeks in, you should be able to determine whether those new buds are male or female. Most growers remove the males from their garden, so they don’t pollinate the females and cause seeds to form.
When growing indoors, the vegetative stage can last one to four months, or even indefinitely in the case of mother plants. You control the length of this phase by the number of hours of light you give your plants. As long as they receive 18 hours, they will remain in this stage.
During the vegetative stage, you’ll need to trade in your fluorescent lights for a metal halide or powerful LED. This blue light mimics the light in spring and sends the message to grow roots and foliage to prepare for the flowers.
If you haven’t already, transplant your cannabis into larger pots and start feeding them more. As they grow, be mindful you will need to increase the PPM of your nutrient solution and transplant them into larger pots as needed.
At this age, your plants need high levels of nitrogen and modest amounts of phosphorus and potassium. Silicon is also beneficial at this stage because it helps to build strength in the stalk and stems, which you’ll need to support those big buds that will soon grow.
As your plants grow taller and fill out, you’ll need to start pruning and training them. This focuses their energy on growing large colas, opens up the plant so light can reach all the leaves, and prevents fungal diseases by increasing air flow.
The general rule of thumb is to flip the lights to 12/12 and trigger the bloom cycle when your plants are about one third of the size you want them to be at harvest.
The flowering stage lasts six to 10 weeks, depending on the strain you’re growing.
You imitate autumn in your garden when you reduce the light to 12 hours on and 12 hours off, and switch to a red high-pressure sodium bulb. This triggers your cannabis plants to start blooming so they can procreate before they die at the end of the season.
The flowering stage lasts six to 10 weeks, depending on the strain you’re growing. During this time, dense buds covered in a sweet-smelling, sticky resin will form on your plants. This resin is where the THC and terpenes are, and so growers do whatever they can to grow the stickiest colas possible.
Your fertilizing schedule will change during this stage. Start feeding your plants minimal amounts of nitrogen, moderate amounts of potassium, and high amounts of phosphorus. This is the time to add bloom boosters and sugars to your regimen.
Be on the lookout for nutrient deficiencies or toxicities during this phase. Brown leaf tips can signal nutrient burn, while yellowing leaves may indicate a nutrient deficiency. It is normal, however, for the lower leaves to turn yellow towards the end of the flowering cycle, when your plants feed on themselves for more efficient nutrition.
Keep feeding your plants until about 10 days before harvest, and then stop fertilizing and flush your crop. This clears your plants of excess nutrients and is crucial to making sure your end product is smooth instead of harsh.
As your buds grow large and dense, environmental conditions and poor air flow can cause bud rot. If you don’t catch it in time, you can lose all of your plants. Keep a close eye on your buds as harvest time approaches. Inspect your buds often and harvest immediately if you see signs of rot. If you catch it early, you can cut the rot out of your buds and salvage most of your crop. You’ll know your cannabis is ready to harvest when the pistils, or the hairs, turn the color of rust and the resin changes from clear to a milky white.
If you understand the life cycle of cannabis, you’ll be able to care for your plants the right way in each stage of their life and anticipate problems before they occur. You’ll be a better grower and have top shelf smoke to prove it.