Growing Marijuana Indoors

This is a simple starting guide on how to grow marijuana indoors. As growers become more experienced, so will the techniques used. As a beginner, its best to keep things simple and that’s what this guide does.                                                                          

Growing Marijuana Indoors

Growing marijuana indoors can be much more complicated than growing outdoors. Without Mother Nature on one’s side, the grower is responsible for controlling the plant’s entire environment, from humidity to temperature to light cycles. There’s a lot to consider. New growers are advised to start with a setup that’s as simple as possible, and with just a few plants. After mastering the art of growing indoors, more complex setups, with more plants, can be used.

indoor marijuana grow room

Marijuana can be grown either from seeds or from clones. Some strains are more suited to indoor growing than outdoor, as breeders have optimized characteristics of certain strains for the indoor environment. Growers that are unsure of what strain they want to grow can consult a marijuana strain selection guide. These guides often highlight past Cannabis Cup winners, which is another good indication of a quality strain.

After choosing what to grow, growers will need to decide where they’re going to grow. Indoors that can be just about anywhere – attics, closets, cupboards, a separate room, or in the basement. This is an important step, as the environment is a deciding factor in most aspects of growing indoors. The space needs to be well-equipped for lighting, possible ventilation, and temperature-controlled.

Because the color white reflects light best, most growers choose a white room, or they paint the walls before moving any plants in. Some growers even take the extra step of installing panda film or Mylar, which are plastic sheets that are black on one side and white or reflective on the other side. These films are much more effective than installing mirrors, and can help the plants get as much light as possible.



Marijuana plants need ventilation in order to thrive. Stale air isn’t good for any vegetation, but the movement of air can help prevent mold from building up on the plants, and can also help strengthen the plant’s stems and leaves as they move. While installations and setups can be extensive and involve things such as connecting into the building’s duct system, ventilating marijuana plants can be very easy.

Choosing a room that has an extraction fan cut right into the ceiling, such as those found in bathrooms, can be a great way to provide ventilation indoors. It’s important to remember however, that the larger the space, the larger the fan will need to be. Extraction fans can be used in conjunction with regular household oscillating fans, as this will help move the air around the room and around the plants. It’s important however, that the fan moves so it’s not continuously blowing on just a few plants; and the fan should be on a low setting so it doesn’t stress the plants.


Choosing containers for growing


Growers have two choices when they grow indoors: they can grow in soil, or they can grow hydroponically. When growing in soil, regular garden pots can be used, but just about any plastic or metal container will work. Because drainage holes cannot be placed at the bottom, as water would spill all over the floor, it’s important that another drainage medium – such as gravel – is used. The soil also needs to be of the highest quality and should be purchased at a greenhouse or a nursery; not just dug up from outside.

For even better results, some growers choose to grow hydroponically indoors. This technique doesn’t use soil, but rather another medium such as perlite, Rockwool, or vermiculite. Growing hydroponically requires several pots to be connected to a reservoir. The reservoir has a pump connected to a timer, and each pot is watered with a nutrient mix on regular intervals throughout the day.

Regardless of whether marijuana is grown in soil or a hydroponic solution, the growing medium does need to be fertilized with nutrients. Over-fertilizing is one of the biggest mistakes beginner growers make, as that can quickly kill an entire crop.


Marijuana Lighting

marijuana indoor grow

All plants need light in order to survive and because there is no sun indoors, the grower needs to provide light with an artificial light source. The standard household incandescent light bulb simply aren’t suitable for growing marijuana, as their light isn’t in the right spectrum, and they’re simply too expensive to run.

The growing cycle of marijuana plants is controlled by light. For the first phase of the growing period, known as the vegetative phase, lights are kept on for approximately 18 hours a day. When the plants are ready to enter the flowering stage and begin producing buds, they only need 12 hours of light a day. This is one of the biggest advantages to growing indoors, as the grower can decide approximately when they want their plants to start producing buds, and simply turn back the lights.

In the simplest terms, there are three types of lighting available for marijuana plants: fluorescent lights, metal halides (MH) and high pressure sodium (HPS) lights. Fluorescent can be used effectively in the cloning and seedling phases, though are not as effective as MH and HPS lights through the rest of the process.

MH lights work extremely well in the vegetative stage, while HPS lamps work best during the flowering stage. Both types of lights however, can work very well on their own for growers that don’t want to be swapping out their lights.  There are many marijuana lighting guides that can help novice growers choose the right lights for them.



When marijuana plants begin to bud, growers need to look closely at those buds to determine whether their plants are male or female. Only females will produce buds and if males are left in the same room as females, they can turn an entire crop to seed. Because of this, it’s important that growers identify males right away, and remove them from the rest of the plants. There are guides on how to sex marijuana plants to help beginners distinguish between males and females.



Marijuana plants grow best at a temperature of about 75 degrees Fahrenheit, or 24 degrees Celsius. However, plants can survive in temperatures as low as 40 degrees Fahrenheit (5 degrees Celsius), or in temperatures as hot as 100 degrees Fahrenheit (38 degrees Celsius.) This means that even if there is a power failure, or the room suddenly becomes too hot or too cold for a short time, it doesn’t necessarily mean that it will damage the plants.


marijuana drying harvest


There are many tips and tricks growers can use to know when it is the best time to harvest, and there are many harvesting guides around to help them. The best way to know when to harvest however, is through experience and simply keeping a close eye on the plants. Plants will show signs when they’re ready to be harvested; the grower just has to know what they are.



Anyone who’s ever smoked marijuana knows that it needs to be dried first. The simplest way is to cut down the entire plant and hang it upside down in a well ventilated room. Marijuana drying guides are available to give new growers a better idea of when it’s time to cut down their plants.

Growing marijuana indoors can be a fun and interesting process, but it can be much more complicated than growing outdoors. It’s important that growers become familiar with all aspects of growing indoors before trying their hand at it. After becoming familiar with simple setups, they can become more extensive, ultimately producing higher yields and higher quality marijuana.


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