plant week

Everything You Need to Grow Weed Indoors, According to Experts

Properly growing just one plant inside a four-square-foot space indoors can yield as many as four ounces of usable bud. Photo: Leaf and Wood

Today, recreational cannabis is legal in Washington, D.C., and ten states, and although its expanded legalization has resulted in a proliferation of new ways to consume marijuana, when it comes to growing the plant, the process is still the same laborious one. “There’s a lot of trial and error,” says Parker Sullivan, the creator of a high-end gadget for preserving a harvest (more on that later), who began growing his own cannabis at 15. (Marijuana laws vary state by state, and aspiring growers can consult this website for more information on what’s allowed — and what penalties they may face — where they live).

If you get the methodical cultivation process right, growing just one plant inside the right four-square-foot space can yield between two to four ounces of bud at the end of the roughly three-month process, according to Sullivan and Robert Pettit, a home grower and the founder of Leaf and Wood (which custom builds cabinets equipped with pretty much all of the items needed to grow cannabis). To find the best things for growing weed yourself, we spoke with Sullivan, Brooklyn-based grower Loki, and Pettit, who say beginners might want to try feminized auto-flowering seeds for ease, and strains that are more sativa than indica because they’re easier to grow (“it’s rare to find one that’s 100 percent one or the other”).

Growing space

Plants grown from auto-flowering seeds will flower regardless of how much time they spend in darkness. Still, Pettit suggests keeping the lights off for six hours a day, and all the experts say a grow space must allow for some sort of ventilation. That’s why tents like this compact model, which has vents to adjust air flow, are the best basic setup for a first grow, according to Pettit. At four square feet, this one has enough space to accommodate a three-gallon pot (which can grow a plant between two- and three-feet high) and other stuff you’ll need, but is still small enough to fit into an apartment or small room, he says.

Both Pettit and Loki swear by Horticultural Growth System’s lights (they’re what Pettit uses in his custom cabinets). This 100-watt LED model is a great “plug and play” option for novice growers, according to Pettit, who recommends getting the light with a 3,000k Kelvin rating because the spectrum is suitable for both vegetative and flowering growth. It comes with cables to attach it to the roof of your tent, where it should be snug against the top so it does not get too close to the plant as it grows.

To better control your grow, our experts recommend plugging the light into a timer, so you can easily set it to shine for the needed hours each day.

You’ll want to keep your grow space (which Loki says is generally 10 to 15 degrees warmer than the room it’s in because of the light) at a temperature between 80 and 83 degrees Fahrenheit, and at a humidity level between 50 to 60. This monitor allows you to keep an eye on both. Small spaces like the four-square-foot grow tent usually don’t require extra tools to adjust humidity — but you can stick a small humidifier inside to increase it, or use DampRid bags to decrease it, according to Loki and Pettit.

To keep air flowing inside the tent, Sullivan recommends getting a four-inch fan and positioning it to blow up toward the top of the plant — but never directly on it, because “you don’t want the plant blowing in the wind.”


All three of our experts recommended that hobby growers use fabric pots for growing cannabis, because their cloth exteriors allow air to pass in and out, which helps the plant from becoming root bound. “The plant will only take nutrients through the tip of its root,” explains Pettit, who says the air that flows through the pot’s fabric will cause roots to naturally split, creating more tips to suck up nutrients. The downside to fabric pots is that they can be hard to reuse, Loki says (which is why it might make sense to get a five-pack like this, in case your first grow doesn’t go as planned). But before you put your seed in the pot, start sprouting it in a shot glass half full of water, according to Loki, who said a little tail will appear between 12 and 24 hours. At that point, you can put the seed in a damp paper towel (and put that inside a ziplock bag) for 24 to 72 hours — you’ll know when it’s ready to be potted when it looks like a little bean sprout. If you’re using auto-flowering seeds, you should plant the bean-sprout-looking thing directly into the three-gallon pot (our experts say auto-flowering plants should live their entire life cycle in the same pot). But if you’re using traditional seeds, you can plant the bean-sprout-looking thing into a smaller four-inch pot, let it grow for between two and three weeks, and transplant it into a three-gallon pot when the plant is about a foot tall.

Place a saucer beneath your pot to catch excess water. The excess can be helpful for determining nutrient levels in your soil, and for gauging when to stop watering, according to our experts.

“The bottom of a fabric pot always stays a little bit wet,” according to Pettit, who along with Loki suggests placing the pot on a riser like this inside the tent to help keep it dry, and prevent it from sitting in stagnant water, which both men say can harm the plant.

Coco is a growing medium made of coconut fiber — it offers more aeration than traditional soil, and allows water to pass through easier, too. “Over the past 30 years it has become the medium many people prefer to grow in,” according to Pettit. He and Loki both suggest it as a more user-friendly medium than soil, which is denser and can lead to overwatering plants — a common pitfall among budding cannabis growers. That said, you should never let coco get completely dry. “You want 40 percent dry before watering again,” Loki says.

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Sullivan recommends having some bamboo stakes and twist ties at the ready to support your plant’s branches “when flowers start to swell and grow juicy buds.”

Water and nutrients

“Overwatering is the first way to ruin a crop,” says Sullivan. He recommends looking at the plant’s leaves as a way to determine when it might be thirsty — if they look like they’re drooping, it likely is. There is no exact science to watering, but Sullivan suggests “between a half-liter and liter of water per gallon of coco every five to seven days.” Alternatively, you know you’re giving enough water when about 10 to 15 percent of what you’re pouring on a plant runs off into the saucer. Sullivan and Pettit both recommend using a one-gallon can with a long spout — which can reach all parts of the plant, and allows you to pour slowly, because watering too fast can compact your growing medium.

Cannabis plants intake nutrients at very defined pH levels — specifically, between 5.8 and 6. Unless you’re growing in a city like New York (where water straight from the faucet generally has the right pH levels), you’ll likely need these products to get your water supply’s pH just right (a few drops of one or the other will often do the trick).