Cannabis home-growing 101: How to cultivate clones, seeds in Colorado

By now, Colorado gardeners are hard at work preparing their soil and remediating their snow-sick lawns in hopes of procuring a bountiful harvest later this year. For those who are still undecided on exactly what to plant, may I suggest adding a different kind of herb to your garden: cannabis.

When Colorado legalized recreational marijuana in 2012, it also legalized home-growing. According to state law, any person age 21 or older is allowed to grow up to six plants at a time in an enclosed area at a private residence. Local laws may have stricter stipulations — for example, the city of Denver limits home-growing to 12 plants total regardless of how many people live at one location — but, in general, it’s permissible to cultivate your own stash.

And because weed plants grow like, well, weeds, the process is also fairly simple. According to experts, anyone with a green thumb can be successful at growing cannabis.

“Think about how you would grow a tomato plant. Make sure it’s got enough space. Make sure at a certain size it’s got enough support, whether it’s tomato stakes or trellising,” said Amy Andrle, co-owner of L’Eagle dispensary in Denver. “If you can successfully grow tomatoes in your garden, you already have an idea of how to do this.”

L’Eagle sells clones, meaning small but well-established marijuana plants, for customers to take home and plant. Andrle has seen demand for those increase among customers over the last several years, which she suspects is due, in part, to normalization. Now that recreational weed has been available for sale for a decade, stigma and fear appear to be subsiding, she said.

Enticed? We tapped local hobby growers and professional cultivators for tips that will help beginners get started. Methods vary depending on preference, but for our purposes, we’ll focus on growing plants outdoors in an enclosed space like a greenhouse. (If you’re interested in growing hydroponically indoors, our sources recommend going to Cultivate Colorado, where the staff can help you find equipment that fits your space and electricity needs. Or consider a smart, all-in-one system like Heyabby for your home.)

Conventional wisdom suggests having your cannabis plants outside in soil by Mother’s Day, but because of Colorado’s unpredictable weather, our experts said it’s fine to wait until June. Those who do put them out in May should cover the plants if a cold snap comes through, Andrle said.

Since planting is only one step of the process, we’ll return to this subject to walk you through caring for your canna-babies during the summer months and then harvesting in the fall.

For now, here are the basics of what you need to get your herb garden going.

The first order of business for all home growers is to decide whether to start from seed or to purchase clones. Both avenues pose benefits, but the essential fact to remember is that only female marijuana plants flower and produce smokable buds.

Buying clones is the less risky bet for two reasons. First, they are guaranteed to be female since they’re typically clipped from a mother plant. Clones are also already well-established, so all gardeners need to do is transplant them.

Finding dispensaries that sell clones, however, can be a challenge. Most will do so in the spring around 4/20 and into the summer months, though L’Eagle sells them year-round to satisfy indoor growers, too. Customers can even add them to online orders and have them delivered to their doorsteps, Andrle said.

The best bet is to look for companies that are vertically integrated, meaning they grow and sell their own products. Not only is transporting clones from one room or facility to another much more easily done in-house, dispensaries that don’t grow marijuana may not have the space or bandwidth to care for the plants.

Aside from L’Eagle, these sites currently sell clones: Seed & Smith (5070 N. Oakland St., Denver, and 1413 Helca Way, Lousiville); Kind Love (4380 Alameda Ave., Denver); Karmaceuticals (4 S. Santa Fe Drive, Denver); Mana Supply Co. (2895 W. Eighth Ave., Denver); and Kind Meds medical dispensary (260 Santa Fe Drive, Denver). The Republic (8401 Baseline Road, Boulder) and Cross Genetics (4902 Smith Road, Unit C, Denver) also plan to do so in the coming weeks and months.

Seed & Smith’s director of cultivation Michael Kesselman said the company is expanding its rotating selection to include all 20 strains that it grows, so home-growers have multiple sativa, indica and hybrid options to choose from. The best way to see what’s currently available is to check social media, he added.

Additionally, those who want a free tutorial can book a tour of Seed & Smith’s cultivation facility in north Denver. Tours run Thursdays through Sundays; claim a spot at seedandsmith.com/cannabistour.

An employee at Seed & Smith cannabis company cuts clones from a mother plant at its cultivation facility in north Denver. (Provided by Lucas Davidson)

Once clones are clipped from a mother plant, they are put in soil to begin growing their own roots. (Provided by Lucas Davidson)

Seed & Smith cannabis company sells clones at both its locations in Denver and Louisville. Check social media to sees which strains are currently available. Additionally, the company offers free tours of its cultivation facility during which staff offers growing tips. (Provided by Lucas Davidson)

Montrose resident Dave Hughes, however, prefers a more hands-on approach. As head breeder for the seed purveyor All We Know is Dank, Hughes is obsessive about plant genetics and contends growers have more options if they decide to purchase seeds.

All We Know is Dank sells both regular and feminized seeds, the latter meaning they are guaranteed to make flowering plants. Those who buy regular seeds receive 12 per order; those who order feminized seeds receive six or seven.

Hughes prefers germinating regular seeds because he’s seen some adverse effects come from the feminization process. But growers won’t know what gender their plant is until the seed grows and the plant matures. DNA testing kits can help novice growers identify the gender, he added.

To sprout seeds, Hughes suggests soaking them in water for 12 to 24 hours, and then putting them between wet paper towels until a white taproot bursts out of the seed. This could take several days, so put paper towels on a plate or the bottom half of a Tupperware container and make sure to spray them so they continually stay moist, he said.

Once a taproot emerges, put the seed in soil to allow the roots to grow. Hughes prefers to start in a small container where the rootball can grow healthy. In fact, he’ll plant the seed a few millimeters down in a Solo Cup first and let the plant grow until it reaches about a foot tall.

“You can take clear cups and poke holes in them obviously, and put a color cup over it, so you can pull the clear cup out and check how full the root zone is,” he said. That will help indicate when it’s time to transplant a seedling.

Keep an eye out for mycorrhiza, or fungus growth, on the roots, which is a good sign and will help the plants absorb nutrients, Hughes added.

After soaking cannabis seeds for 12 to 24 hours, place them in between moist paper towels until they sprout a white taproot. (Tiney Ricciardi, The Denver Post)

Once your seed sprouts a taproot, it's time to put it in soil. Experts recommend placing seeds just a few centimeters beneath the dirt. One trick is to fill a clear Solo cup with dirt and put it inside another colored Solo cup, so growers can see how the roots grow over time. (Tiney Ricciardi, The Denver Post)

Avid gardeners know that having nutritious soil makes for healthy plants, and cannabis is no different. So when the time comes to transplant clones or seedlings, make sure to invest in dirt and nutrients that will help them thrive.

According to Hughes, who also works in customer service and sales at Montrose grow store Build A Soil, using bigger pots will yield bigger plants. He recommends starting with a 30-gallon vessel for each plant (I used 20-gallon pots last year and grew robust plants) or, better still, plant your cannabis directly in the ground.

“You will be able to grow significantly larger plants and have plenty of room for the roots to uptake nutrients and minerals present in the soil,” Hughes said.

Those who want to grow in smaller pots should put their plants outside later in the summer, he added.

Hughes himself follows the Clackamas Coots soil formula, which calls for one-third peat moss, one-third aeration (pumice or lava rock), and one-third compost.

What nutrients gardeners put in their soil may depend on the cannabis strain. That’s because different strains originated in different parts of the world and different environments, Hughes said. For example, sativa strains are native to tropical climates with abundant sunlight, compared to indica strains that are indigenous to mountain and desert regions.

In general, Hughes recommends adding nutrients like crustacean meal, kelp meal, neem cake or karanja cake, and milled malted barley, as well as a variety of minerals.

Build A Soil, which specializes in biodynamic and organic farming materials, sells numerous different nutrient kits, enriched dirt varieties including a Clackamas Coots-approved soil blend, and other additives to meet the desires of specific strains. The company ships across the country.

Once ready to put the cannabis plants in the dirt, find a location outside with unobstructed sunlight. Marijuana starts to flower, or produce buds, when it receives 12 hours of daylight and 12 hours of darkness, typically around the beginning of August. If they get caught in the shade, the plants could be manipulated into flowering early, which is not optimal for their growth or the end product, Hughes said.

Streetlights, house lights and other light sources can also trigger plants into flowering or stress them out, so try to find a spot where they will get complete darkness.

Hughes, Andrle and Kesselman all shared the same piece of paramount advice: Make sure to keep your plants hydrated. Colorado’s arid climate and plentiful sun can quickly dry out marijuana plants, just like vegetables.

The next order of business is pest management, growers said, recommending neem oil as a great natural way to keep bugs at bay. They also suggest referencing any books gardeners may already have in their library since the mitigation process for weed isn’t all that different from other produce.

For biodynamic techniques, specifically, Hughes recommends the “Jadam Organic Farming” series by author Youngsang Cho. L’Eagle also provides customers with clone care instructions when they shop at the Denver dispensary.

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