A Complete Guide To Growing Marijuana Indoors

How Do I Set Up an Indoor Grow?

As you may have heard, several countries have legalized indoor cannabis cultivation. However, it’s not as easy as gardening. There are many factors to consider when it comes to an indoor grow.

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How do I set up an indoor grow? Some basic steps for cultivating indoors are to find a suitable space, the right lighting, and devices that control the room temperature. The steps go on but I’ll stick with the basic steps for beginners.

As you read this article, you will learn about the mediums for growing and maintaining marijuana. Also, I will guide you, step by step, through indoor cannabis cultivation.

A Complete Guide to Growing Marijuana Indoors

Step 1: Find a Place or Room

The first step to cultivating your cannabis is to find a spot in your house to do that. You can find a small room or even just a closet.

Make sure you know how to tailor the device and plants in your designated cultivation room.

Here are some of the factors that you should consider:

Is the Space Big Enough?

You do not have to designate a big space. You can convert any space in your home to a growing area. You can even use a growing tent.

 Is a Power Supply Nearby?

You do not need a lot of power. You just need to have at least two sockets for the light, and maybe use an extension wire.

Do You Have a Water Source? Is It Near the Room?

A pro tip is to never use unfiltered water. Various types of water bacteria could be in there and pollute the cannabis. Use filtered and pure water instead.

How Is the Flooring?

Do not grow your cannabis or start to set up on carpeted floors. Carpet harbors bugs, bacteria, and dust, and holds moisture. Apply reflective sheeting, instead.

Is Noise an Issue?

The lights, pumps, and devices will make some noise. It’s better to make the room soundproof.

Other Variables to Consider:


Room near your space is preferred because cannabis needs regular monitoring. Experienced growers check on their plants every day.

However, beginners must check the plants several times a day until they have it dialed in.

Room Temperature and Humidity

Very warm or very humid house areas create issues with cultivating cannabis.

Designate a place where the plants can access fresh air in a cool and dry area.


You might consider cultivating in an area that nosy neighbors don’t have access to. You don’t want them to create unwanted attention.

Step 2: Configure Your Room Setup

As soon as you designate a room for growing, work on configuring the space. You have three major options: use the entire room, use a room in a room, or convert an enclosed space.

Ensure that what you choose will suit the intensity of the growing lights.

1. The Entire-Room Setup

When using the entire room, one grow light would be insufficient. You will need at least 1 x grow light (ballast + light + reflector) for every 1.2m x 1.2m space.

This is the minimum requirement. Larger rooms will be easier to control if you provide tents.

2. Room-in-a-Room Setup

A grow tent is the cheapest way to go when making a grow room. It is easier to maintain the climate, prevent infestation, lessen the light loss, and protect the room from heat and humidity.

3. Converting an Enclosed Room for Setup

Heat problems are common with small spaces. There are three ways to prevent heat problems.

  • Choose a higher space
  • Use only a 250 – 315W light
  • Ensure a constant flow of fresh air

If the headroom is not that tall, you can use a T5 Grow Light. A grow light is designed for propagation, thus producing less heat.

A constant flow of air can be achieved through holes or fans. An extractor fan can remove the hot air from the top area.

Step 3: Cannabis Grow Lights

The number-one factor in successful indoor cannabis cultivation is lighting. It affects the quality and quantity of your produce.

Choose the best lighting setup for the designated room, but make sure you can afford it.

Also, use reflective sheets to stop unwanted light from touching the plants. They are necessary because they stop light from escaping the room while preventing unwanted light from entering the room.

Natural light and any other unwanted light interferes with the lighting cycle, creates confusion, and stresses the plants.

Following are widely used grow lights:

LED Cultivation Lights

The light-emitting diode (LED) is not a new light technology. However, only recently has it been recognized as an efficient light fixture for indoor cultivation.

LED lights consume the lowest amount of electricity and last longer. They also produce a larger and better quantity of light.

While LED offers these advantages, this setup costs more than that of HID.

The markets have now produced cheaper qualities of LED lights, so be careful to not buy one of these.

The more affordable LED lights were marketed to fool growers and take their hard-earned cash.

HID Cultivation Lights

High-intensity discharge (HID) lights are the standard lighting setup in the industry.

These lights are popular because of their efficiency, value, and combination of output. They do not cost more but are not as efficient as the LED light setup.

Two types of HID lamps are used for indoor growing.

  1. High-pressure sodium (HPS) – HPS is used more during the flowering stage. It is more on the red-orange spectrum.

  2. Metal Halide (MH) – MH is used for the vegetative growth stage. It produces bluish-white lights.

Each HID light needs a ballast and hood reflector. Some ballast is used with either HPS or MH lamps. However, thanks to the newer technology, some ballast will run both.

MH and HPS bulbs are quite expensive. If you can’t afford both of them, start with HPS, which delivers more light per watt than MH.

Digital ballast is more expensive than magnetic ballast. However, it is more effective because it is not hard on your plant.

While digital ballast is better than magnetic ballast, be careful that you don’t buy shoddy ones.

Shoddy digital ballast is not correctly shielded, thus creating electromagnetic interference with signals.

Induction Cultivation Lights

Induction lamps, also known as electrodeless fluorescent lamps like LED light, are not new lighting technology.

However, they have recently been considered to suit the needs of indoor cultivation.

This lamp is more efficient and lasts longer than the fluorescent bulb. It was created by the great Nikola Tesla back in the late 1800s.

Given that this is more efficient than the fluorescent bulb, it is expensive and can be hard to find in stock.

Fluorescent Cultivation Lights

This light fixture – particularly HO T5 bulbs – is popular with smaller-scale growers. Ballast, reflectors, and bulbs are included in a single package, making this setup cheaper.

They are not capable of generating more heat than an HID setup. Thus, they do not require a cooling system.

Knowing that they are cheaper, expect that they will not be as efficient as other fixtures. They generate 20-30% less light per watt of electricity.

Plus, to equal the output of a single 600-watt HPS bulb, 19 four-foot-long T5 HO bulbs are needed.

Tips for Choosing a Grow Light

  • Be realistic about your budget. This includes considering the power consumption rate of the lights.
  • Consider the light output.
  • Consider the space in your setup

Step 4: Provide Air for the Plants

Cannabis, just like other plants, needs fresh air to survive and thrive.

Carbon dioxide and oxygen are essential to the photosynthesis process of plants. You can achieve a regular flow of air by the following means.

  • Exhaust Fan – The exhaust fan will remove the warmer air in the room. Thus, this will be placed near the top of the room.

  • Filtered Air Inlet – The filtered air inlet should be placed on the opposite side near the floor.

Some varieties of cannabis (especially Indica strains) thrive on the colder side of the range, while others thrive at a higher temperature.

For higher temperature cannabis, you have to maintain a comfortable temperature.

Your exhaust fan’s size will depend on the room’s size and the heat that the light generates.

The light system that greatly applies heat is the HID system. If you live in warmer regions, you will want to run your lights often at night to keep down the temperatures in your growth.

Tips for Improving Air Circulation

  • Set up your light fixtures and turn them on for a while.
  • Determine the necessary airflow for a comfortable plant temperature.
  • Add a charcoal filter to the exhaust fan to prevent odor from the cannabis plants.
  • Create an artificial environment by using humidifiers, an air conditioner, and supplemental CO2 (optional for first-time growers).

To achieve an environment that will strengthen your plants and result in fewer pests, maintain a constant light breeze.  

Step 5: Climate Controls and Monitors

It’s time to choose and install the right climate controls and monitors for your indoor cultivation. Some prefer to use expensive, sophisticated units to control the temperature, CO2, and humidity.

If you have just started, you can use a simple 24-hour timer for the light, and an adjustable thermostat.

This is among the most important things that can help your cannabis thrive in the light/dark cycle timing.

The light should be on for 18 hours per every 24-hour period during vegetation growth. During the blooming stage, switch to 12 hours per every 24-hour period.

As indicated in the third step, stress and light confusion will affect the quality of the plants. Always maintain the same lighting schedule every day – hence, the timer.

Optimal Condition for Indoor Cultivation

  • Seedlings/clones: 75-85°F (with lights on), ~70% relative humidity
  • Vegetative growth: 70-85°F, ~40-60% relative humidity
  • Flowering: 65-80°F, ~40-50% relative humidity

Step 6: Cannabis Growth Medium

Every medium has its advantages and drawbacks. This section will describe the popular methods and the media they use.


Soil is the best choice for first-time growers – this is the traditional medium. Soils that don’t contain any artificial fertilizers are the best ones to use.

Artificially fertilized soil will reduce the quality or kill your cannabis.

Super-soil, otherwise known as organic pre-fertilized soil, is an excellent choice for beginners to start cultivation.

You can DIY this soil by combining bat guano, worm casting, and other good components for a soil. Leave it for around a week or two before planting your seeds.


Experienced growers are now switching from soil to soilless. This medium must be fed concentrated solutions of mineral and salt nutrients.

So, beginners should start cultivating by using the traditional medium and working their way up.

The advantage of this medium is the quick uptake of nutrients for the rapid growth of bigger and better produce.

The drawback is that it needs a higher order of precision. Plants are quick to react to over and underfeeding, and are more prone to nutrient lock and burn.

Step 7: Choosing the Right Container

Choose the container based on the medium you’re using. For soil medium, use a 10-gallon nursery pot to grow a few large-sized plants.

For soilless, use small net pots with clay pebbles to grow several little plants.

Plastic bags or cloth bags are inexpensive options, but growers with a bigger budget usually use “smart pots.”

Smart pots enhance airflow to the root zone of the plants.

Cannabis plants are sensitive to water flooding. At the bottom of the container, punch holes.

Then set the containers in trays to ensure proper drainage and keep the plants alive.

Step 8: Feeding the Plants With Nutrients

Cultivating cannabis indoors requires more attention and nutrients than any other indoor plant or crop.

Primary nutrients, otherwise known as macronutrients:

  • Potassium
  • Nitrogen
  • Phosphorus 

The following nutrients are also needed but in smaller quantities than the primary nutrients:

  • Iron
  • Copper
  • Magnesium
  • Calcium

For a pre-fertilized organic soil mix, you must feed your plants at least once a week with the above nutrients.

The reason for cannabis feeding is that this type of plant has a consistent change in macronutrients in every cycle.

When you have the necessary macronutrient product, mix it with water as directed on the label. Use the solution to water your cannabis.

Keep in mind that cannabis is also easily burned, so you must use half-strength only.

Your water’s preferred pH level is between 6 and 7 in soil, and between 5.5 and 6.5 in soilless media.

Consider using a pH meter to check the level. Nutrient lockout occurs when the pH level is above or below the preferred levels.

Step 8: Watering Your Cannabis Plants

Always use filtered or pure water to water your plants. Also, be sure to check the mineral level of the water.

A high amount of dissolved minerals builds up in the roots and interferes with the plants’ nutrient intake.

Meanwhile, a high level of chlorine will eliminate the beneficial microbes in the roots and soil.

Never overwater the plants, as they are very susceptible to fungal root disease. This leads to poor quality.

It is a typical mistake that beginners make.

When Should You Water the Plants?

The most common way to check on whether your plants need watering is to stick a finger down the soil.

After you pull out your finger if you see that it’s dry, it’s time to water the plants.

Another method is to slowly pick up the pot and feel the weight to determine whether it needs watering.

To determine the appropriate weight, after watering a plant, slowly lift it and feel how heavy it is when watered.

This will give you a clue as to what a dry or light plant feels like.

Here are things that you should regularly observe:

  1. Are the leaves dark green, or are they yellowing?
  2. Is the soil wet or dry?
  3. Are the leaves vibrant, strong, and rigid?

How Much Should You Water the Plant?

You will need to consider four factors when it comes to the amount of water your plant needs.

  • Stage of growth
  • Size
  • Outside temperature
  • Overall health

Advantages of Indoor Cannabis Cultivation

  • Climate control – When you are growing cannabis, climate and weather conditions play a significant role. With indoor cannabis cultivation, you can control the room temperature to grow the desired quality.

  • Quality control – The quality control factor is one of the payoffs of growing marijuana indoors. When you grow cannabis indoors, you control the quality and know exactly what you’re getting.

  • Quantity control – You can have a perpetual harvest when you have your own indoor grow.

  • Adaptability – Wherever you live, whatever space you have, you can grow marijuana. If you follow the steps for cultivation, you and your cannabis should do fine.


Overall, marijuana cultivation is always a product of love. Sure, it may cost a lot and take a lot of time, but the payoff is worth it.

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