How to grow cannabis indoors: the beginner’s guide

Anyone can grow weed indoors with some basic equipment and a little know-how.

Apr 21, 2018
How to grow weed indoors for beginners

WASHINGTON, DC – AUGUST 5: Tess Kelly tends to her marijuana plant named ‘Obama Junior’ in her home in Columbia Heights on August 5, 2015 in Washington DC. Kelly, a paralegal for Paul Zukerberg by day is a amateur pot grower by night. Photos by Charles Ommanney/The Washington Post via Getty Images)

There are two big myths about growing marijuana indoors: the first myth is that it’s really easy to grow weed indoors. The second myth is that it’s really hard. It’s true that practically anyone can grow weed indoors. But it takes a little effort and planning. Here’s how to get off to a good start.

1. Pick a grow space

You’ll want to pick a room or closet that isn’t a high traffic area. This is true even if you live where it’s legal to grow your own pot. Remember, rip-offs still happen even when weed is legal. The old axiom about growing weed holds true: The fewer people who know, the better.

There are a couple of considerations to keep in mind when selecting an indoor grow space. The two most important factors are air circulation and vertical height.

You’ll need good air circulation because, like you, a pot plant needs fresh air to breathe. If you keep the plant locked away in a musty closet with stale air, its growth is going to be severely limited. Even with adequate lighting, water, soil, and nutrients, the plant will languish without plenty of fresh air.

That’s why fans are almost always a good idea in an indoor grow space. One or more cleverly placed fans can ensure plenty of fresh air for your plants to breathe.

Vertical height is a little more negotiable, but still a big factor when you grow weed indoors. You’ll need enough space vertically for the plant to develop vegetatively. The vegetative stage of growth determines just how big a plant is when it goes into flower. Bigger plants usually mean better yields.

Don’t despair if your vertical space is limited, though. With careful cropping, pruning, and training, you can successfully grow weed indoors, even with only a few feet of vertical space.

2. Pick a grow light

GettyImages 481593589 Its Official: Michigan is set to vote on recreational marijuana this fall
Photo by: Eye Ubiquitous/UIG via Getty Images

There are several good options when it comes to lighting when you grow weed indoors. The main types of grow lights are high-pressure sodium (HPS), metal halide (MH), light-emitting diodes (LED)  and compact fluorescent lamps (CFLs).

Smaller spaces, especially those where air circulation is a factor, can quickly become too hot with the presence of the wrong grow light. That means if you have very limited space you may want to avoid high-intensity-lighting such as HPS and MH. To keep the grow room temperature under control, consider LED or CFL lighting, as these run much cooler.

If energy consumption is an issue, LEDs are the best bet. They require less electricity than the other kinds of lighting. When upfront cost is a factor, though, many beginners choose CFL lighting, because it’s less expensive than LED

3. Pick a grow medium

There are three main choices for “grow mediums” in which to grow weed. Your choice will impact how you must care for your plants. The three main choices are soil; coco coir fiber; and hydroponics.

Most beginners start with soil, due to its simplicity. You’ll want to get as high quality a potting soil as you can afford. If you know any experienced growers, ask them for their recommendations when it comes to brand names. Don’t use pots or buckets under 5 gallons. You want to give those roots a little space to grow.

Coco coir fiber and other soilless mixtures serve as a medium in which the roots can anchor the plant, without using actual soil. Coco is recycled and processed natural fiber from coconut husks. Its pH between 6.5 and 7.0 makes it comparable to unfertilized soil. It drains and keeps roots oxygenated better than many peat-based soils. Many growers, for this reason, combine coco and soil in a mix.

Hydroponic growers use highly oxygenated, nutrient enriched water. All of the plant’s nutrient needs are supplied through the water by adding a nutrient solution. Since the plant spends less energy growing roots and searching for nutrients, it can use more energy for vegetative growth and flowering.

4. Pick a nutrient regimen

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Young man home growing cannabis on March 09, 2011 in Berlin, Germany. The cultivation of cannabis is illegal in Germany. (Photo by Thomas Trutschel/Photothek via Getty Images)

There are two main types of fertilizer (nutrients) used for growing cannabis: organic and chemical. Both kinds contain the crucial nutrients nitrogen (N), potassium (P), and phosphorus (K). Devotees of organic gardening believe that organic nutrients help deliver superior taste, smell and effects.

The best nutrients for your garden depend partly upon the type of soil or growing medium you are using. The type of plant food used also impacts the acidity of the soil, which makes pH testing important.

Variations in pH have a huge effect on your plants. Cannabis grows best in soil with a pH level between 6.0 and 7. Good growing soils hover around this level. When the pH strays outside this range, nutrients become less available to the plant because they don’t dissolve as well. This is probably the most common problem encountered by beginners who try to grow weed indoors.

Use collected runoff water to measure pH. Products are available (“pH-Up” and “pH-Down”) to adjust the level. Digital pH pens are available to precisely measure the level. Measurement kits are also available which use drops or strips.

Hydroponics setups will need nutrient mixtures specifically made for them. Good hydroponic growers check their pH at least twice a day and quickly make adjustments. They shoot for a basic pH of 6.0, allowing the plants to flower between 5.5 and 6.5.

5. Pick an ideal strain

Good genetics is a crucial factor when you grow weed indoors. No matter how much effort and care you take in growing a plant, you can’t exceed the genetic limitations of its parents. If you use seeds from schwag, the weed you grow probably won’t be as potent as if you use top-shelf seeds.

Selecting the very best genetics you can find means that your hard work will pay off when it’s harvest time. This is how the level of skill and care you exercise can reach its highest potential when you grow weed indoors.

Don’t forget the vertical space factor when choosing a strain. If you have low ceilings or otherwise not much vertical space, an indica is your best bet. They tend to be short and squat, making them ideal for small spaces. Sativas, on the other hand, can get quite tall and gangly, sometimes shooting up to eight feet or more. You can grow them in small spaces, but that can require extensive cropping, training, and pruning.

6. Induce flowering.

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Photo by MIPR Holdinings Via Flickr

You’ll want to leave your grow light on for 18-20 hours a day during the vegetative phase, which is the first part of a plant’s life. But when it’s time to flower, the plant needs to go on a 12-12 schedule of light and dark. The shorter periods of daylight, the plant deduct that it must be autumn, and goes into flower.

You may prefer to turn the lights on and off manually every day and night. But your life is going to be a hell of a lot less complicated if you’ll invest in a simple timer to grow weed indoors. That way, you can be sure the lights are turned off and back on at the precise times needed.

Depending on which strain you picked, the flowering process can take from 6 to 12 weeks (most take 8 or 9 weeks). Indicas tend toward the shorter end of that scale. You can learn the precisely perfect moment to harvest, here. Happy Growing!


Apr 21, 2018