How to Grow Weed In A Closet?

Sophia Delphi May 14, 2022 - 9 min read
Fact Checked
Image of Weed Plants in a Closet

Don’t you love all those photos people post online, showing the incredible grow rooms they’ve set up in their houses, or their outdoor cannabis gardens that look like they should grace the cover of High Times?

It must be nice.

20% of Americans live in apartments or condos, and we’d be willing to bet that the percentage of weed aficionados living in cramped quarters is much higher.

It’s great that more and more states are legalizing pot and allowing people to grow their own supply. But what do you do when you live in an apartment, or even a small house, where you barely have enough room for a couch, a bed, a kitchen table, and your clothes?

No problem. No matter where you live, there are closets. And where there are closets, there are miniature grow rooms just waiting to be set up.

Here’s how to grow weed in a closet.

Why Closet Grow Rooms Require Special Attention

Marijuana plants only thrive with proper temperatures and proper lighting. Unless you’re planning to use an enormous walk-in closet for your grow, you’ll have to take extra steps to overcome those obstacles.

Most closets get hot and stuffy when the door is closed. And they have, at most, a single light bulb hanging from the ceiling. That simply won’t do.

You’re going to need adequate ventilation in the closet, as well as a set of grow lights that are designed to work in small spaces before you can set up your plants and think about the harvest to come.

Watering your crop will require special attention, too. If you over-water plants outdoors, the excess simply drips into the soil. In a grow room, it will probably accumulate on a tile or concrete floor where it can easily be mopped up. But most closets have carpeted or wood floors. That’s a prescription for mold growth (in carpets) or permanent damage (on wood). 

In short, you have a lot of work ahead of you. And you have to be careful if you expect successful grow.

Getting Ready to Grow Weed in a Closet

The first step in setting up a closet grow room: creating an atmosphere that’s as close as possible to the outdoor environment where cannabis plants grow wild.

Before doing anything else, though, clean up the closet. Vacuum and dust thoroughly to get rid of dust and dirt, and be on the lookout for any signs of mold. Now either paint the inside of the closet white or hang white plastic sheets on the wall.

One other note before we set things up: you can set up a grow tent with an irrigation system in a closet, but you’re better off starting off slow. If you’re going to stay in the closet, that would be something to think about in the coming years.

Now it’s time to get some equipment.

Ventilation

Cannabis plants (or just about any plants, for that matter) need free air circulation in order to thrive. They get carbon dioxide from the air, and a stuffy room means they’ll use up all of the available CO2 quickly.

If you’re able to keep the closet door open during your grow, that’s ideal. You may simply want to add a simple oscillating fan to help with the airflow.

A closed-door makes things more problematic. A fan will still help, but installing an exhaust fan (with a carbon filter to absorb the weed odor) in the closet is a far superior approach. You may not want to go that far, since the installation will be a lot of work and could be quite expensive. If you’re planning to grow in the closet for years to come, however, it’s a worthwhile investment.

Here’s a middle ground. Install a few feet of ductwork running to the hallway or room outside the closet, and use a small duct fan to pull the air out. Then drill a few three-inch holes in the wall or door, so fresh air can get in. Problem solved!

Grow Lights

We have one word: LED. (Is that a word, or just initials?) The fancy HID (high-intensity discharge) and CFL (compact fluorescent lights) that are standard in large grow rooms emit quite a bit of heat, not ideal for your small “grow box.” They could easily burn your plants or spur mold growth.

Look for full-spectrum LED 300-600 watt lighting with a temperature of 2000-4000K (Kelvin). That’s the best light spectrum for the flowering stage. Once you’ve gained some experience, you may want to buy separate 4000-7000K lights for your plant’s vegetative stage, or switchable lights that can handle both.

If you can afford more lights, put the big one above the plants, and smaller LED bars (or even small fluorescent lights) along their sides. Good LED lights can be a bit pricey, but the cheap ones may not last longer than a few grow cycles. They have a good investment, though, because they’re extremely energy efficient.

You’ll also need to either be sure to turn your lights on and off manually every day, or buy cheap timers, to make sure the plants get optimal exposure.

Growing Your Weed in a Closet

OK, you’re ready. Let’s grow.

Choosing Your Plants

It goes without saying that there’s limited room available in a closet. For that reason, it’s crucial to grow strains that don’t grow tall or bushy. You can choose indica, sativa, or hybrid strains, as long as you do a little research first. Try Amnesia Haze if you’re a sativa fan, Hindu Kush if you want an indica, or Royal Dwarf for a full-bodied hybrid.

If you’re growing from seed, you might want to avoid regular seeds. They’ll both produce female and male plants, and the males will take up way too much space in your small grow space during the vegetative stage. (You’ll remove the males when flowering begins, but that may be too late.) Auto-flowering seeds will be the easiest to start with.

Also, be aware that sativa and sativa-dominant plants are more difficult to control with pruning, so you’ll have to pay careful attention to them as they grow. 

Growing Medium

Soil is great, but don’t go cheap. High-quality organic soil, which will be nutrient-rich and free of contaminants, is a smart investment.

The other great option is purchasing a small hydroponic system. It will allow you full control over every variable during your grow, while letting you minimize watering and helping the plants grow faster. Hydroponics is expensive, though, so don’t go crazy until you’re sure you’re making a long-term commitment. 

During the Grow

The basics of tending cannabis plants don’t change just because you’re using a closet, but there are some details that require careful attention.

  • Don’t overcrowd the closet. You certainly realize that small plants grow into bigger ones, but it’s easy to get excited and start with too many.
  • Check the garden twice a day to make sure the lights and ventilation are still performing properly, and that they get consistent light exposure each day. Cannabis plants like 18 hours of light a day while growing, and 12 hours per day when flowering.
  • Check the temperature as well. Between 72°-76° is ideal for the vegetative stage and 75°-85°is best for the flowering stage, although it’s fine if temperatures drop as much as ten degrees at night. If necessary, adjust the ventilation or buy a cheap space heater.
  • Maintain a regular watering schedule, starting with once every two or three days during the vegetative stage, and increasing the frequency as plants get bigger.
  • Have a shop vac nearby when you water. You’ll probably be looking at big trouble if water accumulates on the floor of your closet.
  • A hygrometer to check the humidity in your closet can maximize your yield. Vegging plants develop best in 50%-70% humidity; flowering plants prefer 40% to 50%. If you live somewhere dry, you might want to buy a small humidifier. 
  • Trim your plants regularly. If you don’t keep their height and width under control, you’ll end up with a mess – and with diminished bud growth as a result. And train the plants if necessary, with the help of sticks or netting.
  • If the plants are getting too high or bushy, induce flowering early by reducing the amount of light they get each day. Some growers induce the transition by turning out the lights for 24 hours, before moving on to the normal 12 hours per day during flowering.

Congratulations! You’re ready to harvest your first crop – and if you’re like most people, you’re also ready to search for a larger grow room somewhere else in the house or apartment.

How to Grow Weed in a Closet FAQ

Q: Do I have to do anything special to guard against pests getting into my crop?
A: Not really. Pay close attention to the plants, of course, looking for signs of bugs or infestation. The one difference with a closet grow, though, is that you’ll be tending your plants in close quarters, which means you might inadvertently brush up against them and transfer something you picked up outside. Always change clothes before you head into your grow closet, and don’t let your pets get inside.

Q: How many plants should I grow in a normal-sized closet?
A: It’s best to start with just two or three for your first grow. That will prevent an overgrown mess that will damage or destroy your first crop, and will let you closely observe each plant throughout. Once you’ve gotten some experience with growing in a small space, you can make necessary adjustments the next time, and possibly grow a bigger indoor crop.

Q: Will a closet grow allow me to plant and harvest year-round?
A: Absolutely, as long as your closet isn’t in an area of the apartment or house that gets really cold during the winter. Year-round weed is one of the beauties of a controlled indoor grows.