Growing Marijuana Big in Small Spaces

Growing pot in small spaces doesn’t have to be an exercise in futility. Danny Danko breaks down the ins and outs for cultivating cannabis in closets, growboxes and tents.

No Limits

Anytime your space is limited for growing marijuana, some basic rules apply: Since square footage is at a premium, your grow must take full advantage of every available inch. This means choosing between short, bushy, indica-dominant strains such as Hash Plant and Afghani #1, or using drastic trellising and training techniques when growing out sativas like Super Silver Haze, Jack Herer or Kali Mist.

When pruning, start early and do it often. Cut or pinch branches just above the node, where two new shoots will emerge. If you stay on top of this process, you’ll have plants that look like bonsai bushes, with plenty of bud sites but not a lot of stretching or big gaps between the nodes. This is the most efficient way to get bigger yields out of small spaces, but your plants’ vegetating time will increase, so factor that into your schedule.

Don’t prune or pinch plants at all once they begin flowering — you’ll only be decreasing your yields at this point. If the branches are threatening to reach the light, bend them or tie them down to keep them from burning.

A trellis system constructed from chicken wire at the canopy level (a.k.a. the ScrOG or screen of green” system) will further spread out bud sites and increase your yields considerably. Simply train growing shoots to grow horizontally along the bottom of the screen to fill out empty spots.

Ventilate In and Out

Air movement is important in tight situations because fresh, CO2-rich air is quickly depleted, stifling the photosynthetic process and causing new plant-cell growth to slow to a halt. Heat buildup also plays a big role in inhibiting growth in small spaces.

Intake fans must be employed to bring in fresh air. Always use some kind of small micron filter on these fans to avoid bringing in unwanted pests, dust, molds, etc. Set up your intake fans so that they bring in air at a low point, and make sure your exhaust fans suck out air from up high — as we all know, heat rises, so you want to remove the hot spent air and bring in cool fresh air to replace it. An inline charcoal filtration unit on the out- take fan is an absolute must to remove telltale odors from the exhausted air.

A small oscillating fan is another requirement for your micro-grow. Place it at the canopy level in order to keep air moving and avoid stagnation. A good rule of thumb is that if your leaves are always slightly moving, you have good airflow in your garden. If not, add more fans until you see a gentle breeze stirring the leaves.

Light Right

This means choosing the proper lighting for the space you have. I strongly recommend high-intensity discharge (HID) lights such as high-pressure sodium (HPS) or metal halide (MH). Tiny gardens can also use compact fluorescent lighting (CFL), but these lights are best reserved for cloning or keeping mother plants alive rather than flower production.

When using HIDs, a minimum of 50 watts (or 6,000 lumens) per square foot is necessary to maximize marijuana bud production without creating too much heat. A 250-watt HPS light and reflector are perfect for a 2′ x 2′ space. Avoid the overkill of using a 1,000-watt light in a small space and you won’t have to deal with the headache of trying to remove all that built-up hot air. For micro-systems such as a small cabinet, there are even smaller-wattage HPS lights that work perfectly to produce buds without creating too much heat.

Of course, there are also the new LED (light-emitting diode) lamps on the market that provide a decent amount of lumens without creating nearly as much heat. Do some research, though, as these units can be expensive, and not all of them are dialed in to produce plant growth in small spaces. Keep an eye on the technology if you’re interested in this option, since it’s improving quickly and the prices are coming down as well.


Growing in closets is convenient and stealthy as long as you’re able to move the air in and out without arousing suspicion. This might require venting spent air through a hole in the wall inside the closet rather than running curious-looking tubing in and out.

A 3′ x 3′ closet is perfect for a 400-watt light, but look for one with some sort of air-cooling technology that removes heat directly from the sealed, glassed-in hood. Lights with open hoods produce too much heat in small spaces, and you’ll quickly find that your temps at canopy level are too high to sustain explosive plant growth.

Another advantage to closets is that they can be divided pretty easily into two separate spaces using two-by-fours and plywood. This creates a vegetating area for the mother plants, clones and vegging plants and a larger flowering area for budding plants. As long as the budding area is completely dark and light- tight when the flowering light is off, the closet space can be used to perpetually harvest pot without having to rely on purchasing clones or popping seeds for every run.


Grow tents are easy to set up (usually requiring one or two people to install) and just as easy to take down, making them the stealthiest choice for someone who may have a landlord or a meter reader to fool every once in a while. All of them come with holes for outtake fans and secure poles from which to hang your grow lights. Some even have separate chambers for vegetative growth and cloning, making them perfect for people living in one-bedroom apartments or studios with limited space to grow.

Grow tents offer the advantage of mobility, and the best ones are both airtight and light- tight, with flood-proof bottoms to ensure that neighbors aren’t alerted to your project by rain showers from their ceiling. All in all, tents are an affordable and efficient way to get growing in a small space.


Another great investment for people looking to produce their own pot are growboxes. These come in a variety of sizes and prices based on how much functionality they provide. Some are simply metal cabinets with doors and a fan attached, while other, more expensive units use touchscreen technology and computer chips that run virtually every aspect of the grow, from CO2 injection and lighting timers to hydroponic feeding regimens and intake/outtake fans. The better ones can also roll on casters, making them easier to move around an apartment or garage.

Most growboxes run between $1,000 and $5,000. The high-end models may sound pricey, but considering that they can pay for themselves in just a couple of harvests, they are arguably the best way for a micro-grower to go over the long run.

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