How to Grow Marijuana Cannabis Indoors. Type of equipment needed, pros and cons. Benefits of growing weed indoors. How to set up an indoor grow room

1. For more information see https://cannabisnewsforyou.com/ and
https://cannabisseedville.com
How to grow weed indoors
Growing weed indoors is great because you can grow it any time of year and you’ll have complete
control over the plant and what you put into it. Live in an apartment or a small house? Don’t worry, you
can grow weed practically anywhere, even if you don’t have a backyard or a lot of extra space.
Benefits of growing weed indoors
High-quality weed
Although it’s more resource-intensive than growing outdoors and you will likely have to spend more
money on utilities to power equipment, you can control every aspect of your grow environment and
what you put in your plant, allowing you to dial in your setup to grow some primo weed.
Adaptability
Unlike outdoor growing, you aren’t tied to the sun and the seasons. You will be providing the entire
environment the plants need to grow, including the grow medium—soil, rockwool, etc.—and regulating
the amount of water and nutrients they receive, as well as controlling temperature, humidity, and more
for them.
Multiple harvests
You can let your plants get as big as you want, and can control when they flower and when you harvest,
and you can start another batch right away or whenever you want. You can grow any time of year, even
straight through winter or summer, and you’ll get consistent crops each time.
Privacy and security
Even in legal states, you may want to conceal your crop from judgmental neighbors and definitely from
potential thieves. Growing indoors allows you to grow discreetly behind a locked door.
How to set up an indoor grow room
Below is a list of things to consider and equipment you will need to purchase to get started growing
marijuana indoors.
Indoor space
You’ll need a dedicated space for your marijuana plants—you won’t be able to move them around.
Ideally, the space is next to a window so you can vent air from the grow space outside. Growing weed

2. plants smell! Especially when flowering kicks in, you’ll want to redirect air so your house doesn’t reek
of weed.
A lot of people these days buy grow tents for their weed, but they aren’t necessary. You can grow in a
closet, tent, cabinet, spare room, or a corner in an unfinished basement. Just keep in mind that you’ll
need to tailor your equipment (and plants) to fit the space.
It’s a good idea to start small—the smaller the grow, the less expensive it is to set up. Newbie mistakes
will be less costly if you only have a handful of plants. Additionally, most state laws only allow for
growing six plants, but some allow up to 12.
When designing your space, you’ll need to take into account room for your plants, as well as space for
lights, fans, ducting, and other equipment. You’ll also need space to work on the plants. Cannabis
plants can double in size in the early stages of flowering, so make sure you have adequate head space!
Every space is different and there will be a learning curve to growing in yours.
Indoor climate
Cannabis, like all plants, prefers certain environmental conditions in order to thrive. Temperature,
humidity, light intensity, and airflow are all factors that will need to be monitored and regulated in
order to keep cannabis healthy through its different phases.
Although you’ll be controlling the climate inside the grow space, climate outside the grow space will
affect your plants. If the environment outside your grow space is very warm or humid, you’ll have
issues controlling your grow space. Choose a cool, dry area with ready access to fresh air from outside.
If you’re growing in a cold, wet basement, you might have to run a dehumidifier or heater to stabilize
the environment. Conversely, if your space is too hot, you might need to add extra fans or an AC to
cool the plants down.
One trick to avoid hot temps is to have the grow lights on during the evening, when it’s cooler outside,
and leave the lights off during the day when it’s hot. This may help bring down the temps, but you’ll
only be able to work on the plants at nighttime when the lights are on.
Lights
Weed plants need different amounts of light during their vegetative and flowering stages. You don’t
have to worry about this in an outdoor setting—the sun and the season dictate this—but when growing
indoors, you will be controlling it.
Plants need 18 hours of light a day when in the vegetative stage and 12 hours a day when flowering.
The reduction in light from 18 to 12 hours a day is what triggers the flowering cycle—when weed
plants start to grow buds.
Because the amount of light a plant receives is so important, you’ll need to make your indoor grow
space light-tight. Light leaks during dark periods will confuse your plants and can cause them to
produce male flowers or revert to a different stage.
Different lights produce different colors of light. Here’s a brief rundown of the most popular types of
cannabis grow lights used for indoor growing.

3. Can you grow weed indoors without grow lights?
Just about all indoor weed growers use grow lights for their plants. Grow lights ensure your weed
plants will grow healthy and strong, while maximizing yields.
In theory, as long as a cannabis plant can get at least 6 hours of full sun a day, whether inside next to a
window, or outside, you don’t necessarily need a grow light, but pretty much all indoor growers use
them.
HID (high-intensity discharge) lights are the industry standard, widely used for their combination of
output, efficiency, and value. They cost a bit more than incandescent or fluorescent fixtures, but
produce far more light per unit of electricity used. Conversely, they are not as efficient as LED lighting,
but they cost much less.
The two main types of HID lamp used for growing are:
• Metal halide (MH) produces light that is blueish-white and is generally used during vegetative
growth.
• High pressure sodium (HPS) produces light that is more on the red-orange end of the spectrum
and is used during the flowering stage.
In addition to bulbs, HID lighting setups require a ballast and hood/reflector for each light. Some
ballasts are designed for use with either MH or HPS lamps, while many newer designs will run both.
If you can’t afford both MH and HPS bulbs, start with HPS as they deliver more light per watt.
Magnetic ballasts are cheaper than digital ballasts, but run hotter, are less efficient, and harder on your
bulbs. Digital ballasts are generally a better option, but are more expensive. Beware of cheap digital
ballasts, as they are often not well shielded and can create electromagnetic interference that will affect
radio and WiFi signals.
Unless you’re growing in a large, open space with a lot of ventilation, you’ll need air-cooled reflector
hoods to mount your lamps in, as HID bulbs produce a lot of heat. This requires ducting and exhaust
fans, which will increase your initial cost but make controlling temperature in your grow room much
easier.
Fluorescent grow lights
Fluorescent light fixtures, particularly those using high-output T5 bulbs, are quite popular with small-
scale cannabis growers because:
• They tend to be cheaper to set up, as reflector, ballast, and bulbs are included in a single
package.
• They don’t require a cooling system since they don’t generate nearly the amount of heat that
HID setups do.
The main drawback is fluorescent lights are less efficient, generating about 20-30% less light per watt
of electricity used; space is another concern, as it would require approximately 19 four-foot long T5
bulbs to equal the output of a single 600 watt HPS bulb.
LED grow lights
Light emitting diode (LED) technology has been around for a while, and they are getting more efficient
all the time. The main drawback to LED grow lights is their cost: well-designed fixtures can cost 10
times what a comparable HID setup would.

4. But the benefits are great: LEDs last much longer, use far less electricity, create less heat, and the best
designs generate a fuller spectrum of light, which can get bigger yields and better quality.
Air circulation
Plants need fresh air to thrive and carbon dioxide (CO2) is essential to the process of photosynthesis.
This means you will need a steady stream of air flowing through your grow room, which will allow you
to move hot air out of the space and bring cool air in.
This is easily achieved by placing an exhaust fan near the top of the space to suck out warm air—warm
air rises—and adding a port or passive fan on the opposite side of the space near the floor to bring in
cool air. A complete air exchange throughout the entire grow space should occur once every minute or
so.
Without proper airflow, a grow space can experience rapid changes in humidity or develop pockets of
CO2 depletion, neither of which are good for plant growth. CO2 depletion can lead to nutrient lockout,
and areas of high humidity are prone to pest infestation, mold, or mildew.
It’s also a good idea to have oscillating fans to provide a constant breeze in your grow room as it will
strengthen your plants’ stems, making them stronger and healthier.
Setting up fans
For small spaces or tents, clip-on fans can be attached to structures like walls, corners, or support
beams. For larger grow rooms, use medium-sized oscillating fans or big floor models.
Fans should be positioned to provide direct, even airflow throughout the garden. This typically involves
using multiple fans that work together or fans that have oscillation capabilities.
There should be a comfortable airflow both above and below the canopy, and fans shouldn’t blow air
directly onto plants—this can cause wind burn, which makes leaves recede into a claw-like
deformation.
Dehumidifiers and ACs
If your space is too humid, you may need to invest in a dehumidifier—also known as “dehueys.”
However, keep in mind that while dehueys will reduce humidity, they typically increase temperature—
you may need more fans or an AC when adding a dehumidifier.
Getting the right climate for your plants can be a delicate balance involving multiple pieces of
equipment and also lots of electricity. This is part of what makes growing weed indoors more expensive
than growing outdoors.
Fans are a must in a grow space to move air around, so buy some of those before an AC unit. If you
find that fans aren’t bringing down the temperature enough, then you may want to invest in an AC.
Timers/Automation
You will definitely want to invest in a timer for your lights. Because the amount of light a plant
receives dictates its vegetative or flowering stage, it’s important to give it a consistent amount of light
every day, and that’s done with a timer. It’s a good idea to check your timer at least once a week to
make sure it’s working properly.

5. You can also use a timer for your fans, but a thermostat is better—you can set it to a specific
temperature, and the fans will turn on when it’s too hot and turn off when it’s too cold.
Most dehumidifiers and ACs have built-in thermostats, but if they don’t, you’ll want to buy an external
one.
For growers who have a little extra money to spend and want full control over their indoor garden,
environmental controllers will allow you to automate the process. These devices are essential for if
you’re away from the garden for a long period of time.
You can connect a controller to fans, dehumidifiers, humidifiers, heaters, or air conditioners, and set
thresholds whereby each device will power on and off based on your ideal environmental settings.
Some units run autonomously, making changes based on set parameters, while others allow you to
control each element via an app on a phone, tablet, or computer.
How to regulate temperature and humidity when growing weed
indoors
You’ll need to ensure that temperatures remain within a comfortable range for your plants, between 70-
85°F when lights are on and between 58-70°F when off. Some varieties of cannabis—generally indicas
—prefer the colder side of the range, while others—typically sativas—are more tolerant of high
temperatures.
For the most part, weed prefers these temps at each growth stage for optimal health:
• Seedlings/clones: 75-85°F; ~70% relative humidity
• Vegetative growth: 70-85°F; 40-60% relative humidity
• Flowering: 65-80°F; 40-50% relative humidity
The two factors you need to control to dial in the environment are temperature and humidity.
Inevitably, there will be fluctuations of temperature and humidity in your cannabis garden. These
fluctuations can occur both throughout a grow space as well as within pockets inside a given room.
They can also occur at different points within a given day or throughout a season as conditions change
in the environment outside your grow space.
It can be tricky getting the right balance of temperature and humidity because they affect each other—
turning up your dehumidifier will lower the humidity of your grow space, but it will also increase the
temperature of the area. This in turn may require you to turn on an AC unit—everything’s connected!
Tools to measure temperature and humidity
Equip yourself with these cheap and easy-to-use tools to take measurements in your indoor cannabis
setup:
• Thermometer: A basic one will allow you to measure how warm or cool the environment is
inside your garden.
• Hygrometer: This measures humidity, or more specifically, water vapor content in the air.
• Infrared thermometer, or IR thermometer (optional): IR thermometers use a detection device
called a thermopile to measure surface temperatures. Although not necessary, these are helpful
in finding out leaf temperatures, which will give you an extra layer of knowledge on how to
properly regulate environmental conditions.

6. Regulating temperature
Controlling temperature in your indoor grow room or cannabis garden can be achieved by manipulating
these factors:
• Lights: Different grow lights will give off different heat signatures. Hot lights such MH, HPS,
and fluorescents produce much more heat than LEDs. Also, lights can be raised or lowered to
change temperature at the canopy level.
• Airflow: You can remove warm air (up high) out of the garden and bring in fresh cool air (down
low) with fans and ducting. Fans can also help exchange air throughout your canopy, cooling
leaves in the process.
• ACs: You may need to bring in an air conditioner to rapidly cool the overall temperature of your
grow space if it’s too hot and fans aren’t enough.
• Heaters: Some gardens may require warm air, especially during times when lights are off and
not generating heat.
How cold can weed plants handle?
When temperatures fall below 50°F, it can slow a weed plant’s growth and negatively impact the plant.
Colder still and the plant could freeze.
Regulating Humidity
Humidity is the amount of water vapor in the air. Here are some ways to control it in your marijuana
grow room:
• Dehumidifiers: Dehueys remove moisture from the air but also increase temperature.
• Airflow: As with regulating temperature, regulating airflow will allow you to move moisture in
and out of your grow space and control humidity—simply opening up a space, i.e., opening the
door to your grow room or tent, can bring down humidity.
• Humidifiers: A humidifier can add water vapor to a grow space and increases moisture levels if
it’s too dry.
• Water: In the absence of a humidifier, you can mist plants with a spray bottle to create extra
moisture.
Soil and other media for growing weed indoors
There are many different media to choose from, including good ol’ fashioned pots full of soil, rockwool
cubes, a hydroponic tray, and more.
Soil is the most traditional medium for growing marijuana indoors, as well as the most forgiving,
making it a good choice for first-time growers. Any high-quality potting soil will work, as long as it
doesn’t contain artificial extended release fertilizer—like Miracle Gro—which is unsuitable for
growing good cannabis.
Good soil for cannabis relies on a healthy population of mycorrhizae and soil bacteria to facilitate the
conversion of organic matter into nutrients that a plant can use. Alternately, you can use a regular soil
mix and then supplement your plants with liquid nutrients.

7. Finding the right soil for cannabis
For most first-time gardeners, we recommend buying a quality potting soil that will provide your plants
with enough nutrients to get them through most of their growth cycle without having to add many
amendments or liquid nutrients. This pre-fertilized soil—often referred to as “super-soil”—that can
grow cannabis plants from start to finish without any added nutrients if used correctly.
You can make this yourself by combining worm castings, bat guano, and other components with a
good soil and letting it sit for a few weeks, or it can be purchased pre-made from a local nursery or
grow shop.
While shopping for soil, you might be overwhelmed by the options available at your local garden store.
The soil type is the basic structure of your soil. From there, look at nutrients, microorganisms, and
other amendments that improve the soil. Your choices will be flooded with words like:
• Perlite
• Worm castings
• Bat guano
• Biochar
• Peat moss
• Compost
• Fish meal
• Bone meal
• Glacier rock dust
• Plant food
These are just some examples of amendments commonly used in different types of soils. Heavily
amended soils will have long lists that break down all organic nutrients they contain. Some companies
create soils that offer a great structure with base nutrients, but allow you to fill in the gaps as you
desire.
Soil temperature for cannabis
Soil should be in the 65-75°F range, or about the temperature of your grow space. If it seems like soil is
getting too hot under grow lights, add some water on the cold side next time you water.
What soil temperature is too hot for weed plants?
A soil temperature above 80°F for a plant isn’t ideal. When soil gets that hot it can be difficult for roots
to uptake nutrients.
Hydroponics
Hydroponics is a system of growing weed without soil. Plant roots are suspended in water, which is
constantly recycled throughout the system. One of the main benefits to growing hydro is that roots have
easy access to nutrients. Many argue that you can grow bigger, more potent buds with hydroponics.
Can you grow weed indoors without hydroponics?
Hydroponics is an advanced form of growing that experienced growers may take on, but indoor
growing can be done with soil and pots for all levels of growing experience, and is much cheaper and

8. easier than dealing with hydroponic systems.
Growing containers
What type of container you use will depend on the grow medium, the system, and the size of your
plants.
Inexpensive options include standard plastic pots or cloth bags, while some growers choose to spend
more on “smart pots” or “air pots”—containers designed to enhance airflow to the plant’s root zone.
What size pot do I need?
Many growers will start plants in a one-gallon pot and then transplant up to a bigger pot as plants get
bigger. A lot of growers will transplant once, from a one-gallon to a five-gallon pot, and harvest from
there. If your plants get bigger, they may need a seven- or ten-gallon pot.
What to look for in a pot
Your cannabis wants a safe, healthy place for root development. Without healthy roots, your cannabis
will never thrive. Roots are in charge of water retention, nutrient absorption, anchoring the plant, and
they also facilitate vegetative growth.
Drainage is key, as cannabis plants can get waterlogged and develop root rot. If you repurpose
containers, be sure they have holes in the bottoms and set them in trays.
For a root system to develop and thrive, they will need the following:
• Drainage: Water retention is paramount for healthy plants—without it, your cannabis will
wither and die. But too much water will waterlog your plant and lead to root rot, killing roots.
• Oxygen: Plant roots require oxygen to function properly. Choose a container that facilitates
enough oxygen for root development without overexposing them to the elements—containers
do this though various styles of perforation.
• Nutrients: Roots require optimal conditions for nutrient absorption to occur. This includes pH
balance, optimal temperatures, and nutrient availability.
• Space: Roots need plenty of space to branch out. A container that is too small will cause it to
become rootbound and choke the plant.
Traditional plastic containers
Standard plastic containers are a popular option for growers operating on a budget. These pots are
inexpensive and provide the essentials for your plants.
Pros:
• Low overhead costs
• Solid drainage (plus it’s easy to add more holes)
• Transplanting is easy and inexpensive
Cons:
• Can’t protect root systems from temperature fluctuations as well

9. • Lack of durability which can cause cracks and structural damage over time
• May have airflow issues depending on the grow medium
Fabric containers
These are quickly becoming the standard. Roots in fabric pots grow to the outer edges and attempt to
bypass the porous fabric wall but are cut back, allowing new growth to occur. This process, called “air
pruning,” results in a denser root composition which promotes healthy growth and development.
Pros:
• Promotes dense, healthy root systems
• Increased airflow to roots
• Excellent drainage
Cons:
• Require more attention and maintenance because they dry out quickly. Note: You can use larger
pots to help slow drying.
• Flimsy structure can make plant support challenging
Ceramic pots
Terra cotta pots offer a unique set of benefits to growers in hot climates.
Pros:
• Absorb moisture and retain lower temperatures during hot days
• Heavy weight helps to anchor larger plants
Cons:
• Less than optimal drainage; drilling holes into clay pots is possible but requires special tools
and is labor-intensive
• Heavy weight makes it difficult to transport plants
Caring for your indoor cannabis plants
When starting with clones or seedlings, you’ll want to check your plants every day because they’re
delicate and sensitive to environmental conditions. You may need to adjust temperature and humidity
levels in your indoor grow space at first to hit the sweet spot for your plants.
As your indoor weed plants grow, they’ll need less attention, but you’ll still need to check up on them
every 2-3 days.
Watering
Best water for growing weed
The cleaner the water, the better for your plants, but you don’t need to buy a bunch of distilled water.
Generally speaking, if you’re only growing a few plants and your tap water is good enough to drink,
it’s probably fine for your weed plants.

10. You can invest in an EC (electrical conductivity) meter, which measures the dissolved salts of your
water, to be sure. Plain water should be between 50-300 ppm.
Ideal water temperature for growing weed
Water shouldn’t be too hot or too cold—keep water temperature between 65-75°F. Cold water can
shock the plant and make it difficult for roots to absorb. Excessively hot water can damage plants.
When growing weed indoors, you’ll likely have to add nutrients to your plants. You won’t need to add
nutrients every time you water, but get on a schedule where you water every other time, or two on, one
off.
Before watering, check the pH of your water and add pH Up or Down if needed.
Do weed plants like warm or cold water?
If anything, use water on the cold side, rather than the hot side. Under 65°F will slow nutrient uptake,
but water above 75°F can damage a plant.
Nutrients
If using nutrients, estimate how much water you’ll need for all of your weed plants so you can measure
out and mix in the appropriate amount of nutrients.
Remember, a common mistake newbie growers make is to overwater plants.
Check out our Guide on nutrients for more info.
Check for pests, mold, or nutrient deficiencies
You’ll also want to take this time to check over your weed plants for pests, mold, or nutrient
deficiencies.
Examine the tops and undersides of leaves for pests or discoloration—spider mites live on the
underside of leaves—as well as stalks and branches. Also, check the soil for pests.
Equipment
Make sure all equipment is on, no breakers have flipped, and everything is running smoothly. Check
lights, timers, fans, dehueys, ACs, and anything else that plugs into the wall or has a battery.
Think of all the equipment in your grow space as organs in the body—if one fails, the others will have
to work a lot harder for a bit, and then will fail in a matter of time.
Daily maintenance checklist for your indoor marijuana grow
• Water plants
• Check pH of water
• Measure and mix nutrients
• Check plants and soil for pests, mold, nutrient deficiencies
• Prune/remove dead leaves on plants if needed

11. • Determine if plants need topping
• Make sure plants are spaced properly and not shading each other out
• Adjust level of lights if leaf tips are getting burned
• Check temperature and humidity in grow space
• Check equipment is running properly, i.e., lights, timers, fans, dehueys, etc.
Indoor marijuana grow timeline
The growth stages of marijuana can be broken down into four primary stages from seed to harvest:
• Germination (3-10 days)
• Seedling (2-3 weeks)
• Vegetative (3-16 weeks)
• Flowering (8-11 weeks)
Generally speaking, it takes anywhere from 10-32 weeks, or about 3-8 months, to smoke what you’ve
grown. (It’ll be quicker if you start with a clone or an autoflower seed.)
That’s a big variance, but it really depends on how big you want your plants and how often you want to
harvest—you can have multiple harvests of smaller plants, or less harvests of bigger plants.
For example, it takes less time to grow 3′ weed plants than 5′ plants; in the span of a year, you can
maybe grow four harvests of 3′ plants, or two harvests of 5′ plants.
You’ll likely yield about the same amount of weed in both cases, but more harvests mean you’ll have
fresh weed to smoke more often and have more opportunities to grow different strains. But more
harvests also means more work in cleaning up the space between harvests, trimming, etc.
The biggest variability in how long a marijuana plant takes to grow will happen in the vegetative stage
—after the seedling phase and before flower.
The flowering stage will always take about eight weeks—some strains take seven, some nine, some
even more, it depends on the strain.
So when growing weed indoors, you can control the size of your plants by flipping them into flower
whenever you think they’re big enough in the vegetative stage.
Check out our Guide on marijuana plant growth stages for more info.
Odor control in your indoor marijuana grow
As much fun as growing marijuana indoors is, having a home that perpetually smells like fresh weed
can be a serious inconvenience, if not to you than possibly your neighbors. Although weed odor from a
small indoor grow in a closet is much easier to manage than a large grow with several flowering plants,
both can produce pesky odors that will permeate an entire home if left unattended.
Plants in the vegetative stage maintain a low odor as they haven’t begun to produce terpenes, the
plant’s aromatic compounds. As weed plants transition into the flowering phase, trichomes will start to
develop and produce terpenes, causing them to smell more.
Here are some ways to mitigate odor when growing weed indoors.

12. Check temperature and humidity levels
The first step in odor control is making sure temperature and humidity are under control in your grow
space—high temperature and humidity will perpetuate odors.
As your plants get bigger and especially when they start flowering, they’ll start to smell more.
Outfitting your grow with a dehuey or AC can help bring odor down.
Make sure air is circulating through your garden
Proper air circulation will help maintain temperature and humidity, and also bring down odor. Ideally,
air needs to move through a garden every few minutes, and you should create a vent to the outside.
Oscillating fans, and intake and exhaust fans can move air through your garden quickly, taking odors
out with them.
Odor absorbing gels may help
Odor becomes much more difficult to manage in the final six weeks of a marijuana plant’s life, when
trichomes and terpene production ramps up. You can also get odor-absorbing gels, which replace weed
smells with other scents. Keep in mind that odor gels don’t eliminate odors, but simply mask them.
Activated carbon filters
These come in different shapes and sizes and are a great way to get rid of odor in an indoor weed grow.
Also known as “carbon scrubbers” for their ability to get contaminants out of the air, these employ
activated and highly ionized carbon to attract particulates responsible for carrying odor, such as dust,
hair, mold spores, and volatile organic compounds, and traps them in a filter.
Carbon filters usually work best when positioned at the highest point in your grow space, where the
most heat accumulates.
Article by Patrick Bennett and Trevor Hennings
For more information see https://cannabisnewsforyou.com/ and
https://cannabisseedville.com