Growing marijuana indoors: Beginners guide to growing weed indoors

Follow our step by step guide on growing marijuana indoors and you’ll be enjoying your home-grown weed in no time at all.

This guide to growing weed indoors will ensure you grow your marijuana in a professional, tried-and-tested manner. The techniques and methods are the result of extensive research on growing marijuana indoors.

Our guide to growing marijuana indoors is for the beginner weed grower, and anyone interested can follow. Our cannabis growing methods are easy to implement and understand. Your weed will be growing lushly before you know it.

Even though we keep things simple, growing marijuana indoors is not always an easy task, but getting your weed growing beautifully is not that hard either. Just keep reading and you’ll be armed with the easiest and coolest ways to grow wonderful, aromatic cannabis.

Growing marijuana indoors

Our step by step growing marijuana indoors guide is better than most out there because we provide concise content and workable techniques and ideas. None of the content is irrelevant to growing quality marijuana, so read every word

Our motivation is simple! We want to teach you how to grow marijuana indoors in the easiest way possible. When you have successfully accomplished the task of growing marijuana indoors, we will have achieved our goal. If you are looking to cultivate your own weed, you are definitely at the right place!

Growing marijuana indoors - yellow

Let’s get started and happy marijuana growing!

Step 1: Choose a space for growing marijuana indoors

The first step to learning how to grow marijuana indoors is to choose a suitable area or space to grow your weed. Your grow space can be as big or as small as you like.

Indoor marijuana growing areas range in size

Your cannabis growing area doesn’t have to be an entire room. It can be a closet, cabinet, tent, empty area in the basement, spare room or any available indoor space. You will need to adjust your equipment choices to suit the space you choose.

Growing marijuana indoors is like most things in life: start small and take it from there, but don’t forget to leave room for expansion.

There are numerous reasons to start small!

  • A smaller grow is far cheaper to set up.
  • Monitoring only a few plants is a lot easier when you’re still a novice weed grower.
  • Mistakes cost a lot less when your cannabis grow is smaller. Let’s face it: everyone makes mistakes. Anyone can lose a plant to disease or pests.

Growing marijuana indoors requires foresight

There a few more factors you need to take into account when choosing your marijuana growing space:

  • In addition to your plants, your area needs to accommodate your lights, fans, ducting and other gear.
  • You also need to have room to work, or you’ll be falling over your cannabis plants causing all kinds of havoc.
  • Your marijuana plants will double, and then triple, in size in the early stages of flowering. Make sure your area is big enough and you have adequate head space for your plants. You also need place for you to maneuver around your marijuana plants.
  • If you’re growing marijuana indoors in a small space such as a cabinet, tent or closet, you need to leave yourself some elbow room to remove the plants when working on them.

Your cannabis grow space should be easy to clean

Sanitation is crucial for growing marijuana indoors. Ensure that your space can be cleaned easily. Avoid surfaces like wood or carpeting because they are hard to keep clean. Easy-to-clean surfaces are a must.

Ensure that there are no light leaks in your grow space.

Your marijuana growing area must be light-tight! This is crucial. Light leaks during dark periods can confuse your plants and lead to issues. For example your cannabis plants could produce male flowers as a result of light getting into the space.

Growing marijuana indoors - room

Personal considerations about growing marijuana indoors

There are a few more personal variables to keep in mind when selecting your dedicated marijuana growing area.

  • Accessibility: Indoor marijuana plants need careful monitoring. Choose a convenient area where you can check on them frequently (at least every day). Novice growers will want to check their weed plants a few times a day. Whatever your experience level, it is ideal to grow your plants in convenient and easily-accessible area.
  • Climate concerns: Natural temperature and humidity are important factors when choosing your marijuana growing area. Select a relatively cool and dry area, with access to plenty of fresh air from outdoors. If your marijuana growing area is very warm or humid to begin with, you may have issues controlling your grow environment.
  • Secrecy: Depending on where you live, stealth and secrecy may be important. If you need to hide your marijuana grow from inquisitive people, such as neighbors, thieves, or others, choose a growing area that isn’t subject to unnecessary scrutiny or where the noise of your equipment may attract unwanted attention.

Step 2: Choose suitable grow lights for growing marijuana indoors

To ensure a quality yield, your marijuana growing room needs to be equipped with quality grow lights. Grow lights are a very important factor in the quality and quantity of your marijuana crop. It is imperative that you go with the best grow lights you can afford.

Here is a summary of popular marijuana grow light types that are used for growing marijuana indoors.

HID Grow Lights

These lamps are the industry standard and the  most common lights in use. HID stands for High Intensity Discharge. Cannabis growers use them for their efficiency and output. HID grow lights provide good value for money, but can be a bit pricey. They are more expensive to buy than fluorescent or incandescent lights. The reason they are so widely used is because they produce a lot more light per unit of electricity used.

Growing marijuana indoors - HPD light

HID grow lights generally fall into two categories:

  • Metal Halide (MH) grow lights: These produce light that is blue-white in color. They are typically used during vegetative growth. Vegetative growth is the second stage in the life of a plant after it completes germination and begins photosynthesis.
  • High Pressure Sodium (HPS) grow lights: These produce light that is red-orange color. These are typically used during the flowering stage

HID lighting systems also need a ballast and hood/reflector for each light, in addition to bulbs. Newer ballast designs accommodate both types of lamps, but older systems are type-specific.

If you are on a strict budget, you can start out with HPS lamps because they produce more light per watt. HID lights are not as cost-efficient as LED lighting, but their price tag is about 90% less.

Ballasts for HID grow lights

When it comes to choosing ballasts, be aware that magnetic ballasts have a cheaper price tag than digital ballasts. On the downside, they do run hotter, are not as efficient, and are tougher on your bulbs. If you can afford to, go for digital ballasts. They are a superior and better option, but of course are more expensive.

A word of caution: there are a number cheap digital ballasts on the market, but they are just not worth it. They are often not well shielded and can also create electromagnetic interference which can affect your WiFi and cause other issues.

Unless your cannabis growing space is large and open, with plenty of ventilation, you’ll need air-cooled reflector hoods to mount your lamps in. This is because HID bulbs produce a great deal of heat. Ducting and exhaust fans are necessary to achieve this. While this will add your initial cost, it will definitely allow you to control the temperature in your growing room far more easily.

T5 Fluorescent Grow Lights

Fluorescent grow lights, particularly those using high-output (HO) T5 bulbs, are fairly popular for growing marijuana indoors on a small scale as a hobby.

The main reason for their popularity is that these grow lights are less costly to set up, because the bulbs, ballasts and reflectors typically come in one package.

Marijuana hobbyists also like them for growing marijuana indoors because they generate far less heat than HID bulbs and therefore do not require a cooling system.

The main downside is that fluorescent grow lights are not efficient. These lights produce approximately 20-30% less light per watt of electricity used.

Another concern is space. Florescent lights require about 19 four-foot long T5 HO bulbs to produce the same output as a single 600 watt HPS light.

Growing marijuana indoors - T5 lights

LED Grow Lights

Light Emitting Diode (LED) grow lights have gained popularity recently for growing marijuana indoors. While the technology has been around for some time, LED lighting systems have only been adapted recently. LED grow lights make super-efficient grow lights for growing marijuana indoors.

The main negative factor is their cost. LED grow lights are expensive and a system could cost up to 10 times that of a comparable HID setup.

On the upside, there a many factors to counterbalance the cost. The considerable benefits of LED grow lights are they:

  • Last a lot longer,
  • Use considerably less electricity,
  • Produce a lot less heat.

The best LEDs also produce a “fuller” spectrum of light. Experts say this factor alone can produce larger yields and superior quality.

A word of caution! There are a lot of inferior LED products on the market that are being passed off as good. Do your homework thoroughly before investing in LEDs.

Growing marijuana indoors - LED lights


Induction Grow Lights

Induction grow lights are also fairly popular among indoor marijuana growers. There lights are also know as electrodeless fluorescent lamps. The technology has been around since the 1800s, but has only recently been adapted for growing marijuana indoors.

Induction lights are basically fluorescent bulbs that are more efficient and last longer.

These lighting systems are both expensive and hard to find.

Growing marijuana indoors - induction light

Step 3: Choose a ventilation system for growing marijuana indoors

A steady flow of air in your grow room is essential for growing marijuana indoors. Cannabis plants need fresh air to grow and thrive. Carbon dioxide (CO2) is essential to the photosynthesis process.

There are two ways to ensure your cannabis plants are well ventilated:

  • A basic exhaust system,
  • A sealed environment.

Setting up a basic ventilation system for growing marijuana indoors

A basic ventilation systems consists of:

  • An exhaust fan to remove warmer air,
  • An air inlet to introduce cooler air.

To achieve sufficient ventilation, you can place an exhaust fan near the roof of the room, and a filtered air inlet near the door on the opposite side.

The goal is to ensure that your plants grow in a comfortable temperature range. The ideal range is:

  • Lights on: 70 to 85 degrees,
  • Lights off: 58 to 70 degrees F.

Your ideal temperature within these ranges depends on the variety of cannabis you are growing. Indica strains typically prefer lower temperatures, while others tolerate higher ones.

The size of your exhaust fan depends on two factors: the size of you growing area and the amount of heat produced by your grow lights.

HID systems put out a lot of heat, especially if they aren’t mounted in air-cooled hoods.

Growers who live in warmer climates often run their lights throughout the night to keep temperatures down in their grow room.

To determine the amount of ventilation needed, set up your lights and leave them on for a while. When the temperature has settled you’ll be able to determine the amount of airflow (and the size of exhaust fan) needed to maintain the ideal temperature for growing your marijuana plants indoors.

Tip: Add a charcoal filter to your exhaust fan to reduce the odor of your marijuana plants in bloom time.

Setting up a sealed environment for growing marijuana indoors

As an alternative to an exhaust system, you can create a sealed environment for growing your marijuana indoors. These typically consist of an air conditioner, dehumidifier and supplemental CO2 system. This option is pricey and for beginners we suggest setting up an exhaust system.

Ensuring a light breeze for your indoor marijuana plants

In addition to ventilation, it is a good idea to ensure that there is a light breeze flowing through your grow room. This will strengthen the stems of your cannabis plants and reduce the risks from mold and flying pests.

A circulating fan works best for this purpose. You can mount it on the wall, but be careful not to point it directly at your plants, because this could cause windburn.

Growing marijuana indoors - fan

Step four: Choose a control and monitor system for growing marijuana indoors

Once you have selected your lights and climate control equipment, the next step to growing marijuana indoors is to automate these elements.

Controlling the lights in your cannabis grow room

As a beginner, all you basically need is a basic 24 hour timer for the lamps and an adjustable thermostat switch for the exhaust fan.

While there are state-of-the-art systems on the market, they come with a price tag to match. Sophisticated systems can control lights, temperature, humidity, and CO2 levels, but they are unnecessary in the beginning.

The timing of the light to dark cycle is very crucial when growing marijuana. As a rule of thumb, you should switch your lights on for:

  • 16-20 hours per 24 hour period while the plants are in vegetative growth, then;
  • 12 hours per 24 period when the plants are in bloom.

A light timer is essential because it is important that the lights turn on and off at the same times every day. If you don’t do this you run the risk of stressing your plants.

Controlling and monitoring ventilation of your marijuana plants

It is possible to use a timer on your exhaust fan, but a thermostat switch is a far superior option for growing marijuana indoors.

The basic models allow you to simply set the thermostat on the device to the maximum temperature for your grow space and plug your exhaust fan in. When the temperature reaches the set level, the fan turns on until the temperature falls below the set threshold. This saves energy and maintains a steady temperature.

A hygrometer/thermostat combination (with high – low memory feature) can also be very handy for monitoring conditions in your grow room. These devices record the current temperature and humidity level, as well as, the highest and lowest readings since you last checked. They are inexpensive and well worth it if you need to be away for longer periods of time.

Ensuring the pH balance of your marijuana plants

Cannabis plants prefer a pH between:

  • 6 – 7 in soil, and
  • 5.5 – 6. 5 in hydroponic media.

Letting the pH get out of this range can lead to nutrient lockout.

You should always have a pH meter or test kit on hand to check the pH levels of your water, nutrient solution and soil.

If nutrient lockout occurs your plants will be unable to absorb the needed nutrients. You need to test your water and soil regularly, and make sure your nutrient mix falls within the desired range.

Growing marijuana indoors - pH

Step 5: Choose a grow medium for growing marijuana indoors

There are many different ways to grow plants indoors. Methods range from soil in pots to slabs in hydroponic trays. Every medium has advantages and disadvantages. The most common choices for growing marijuana indoors are:

  • Growing in soil.
  • Using hydroponics (growing without soil – soilless).

Growing marijuana plants indoors in soil

Growing in soil is the most common and traditional way to raise cannabis plants. It is also the method most like to succeed for the novice weed grower. This is how we recommend you start out.

To grow your plants in soil, the most important element is high quality potting soil. Any brand will work, provided it does not contain artificial, extended release fertilizer.

Super soil is a great soil to start out with. It is an organic pre-fertilized soil is a great choice for novice weed growers. You can use it to grow marijuana plants from start to finish. Provided you use it correctly, you won’t need to add any nutrients.

You can make super soil yourself by combining bat guano, worm castings and other components with a good basic soil and leaving it to stand for a few weeks. A far simpler option is to buy pre-made super-soil.

The super soil organic growing method relies on a healthy population of mycorrhizae and soil bacteria to facilitate the conversion of organic matter into nutrients to sustain the cannabis plants.

You can also simply use regular soil mix as an alternative to super soil. You will then need to feed your marijuana plants nutrients.

Using hydroponics to grow your marijuana plants indoors

Soilless growing, or hydroponic media, is becoming more and more popular for growing marijuana indoors.

The hydroponic method requires feeding the plants concentrated solutions of mineral salt nutrients. The roots of the cannabis plants absorb the nutrients directly through the roots by the process of osmosis. Because the nutrients are absorbed more quickly, this leads to faster growth and larger yields.

The major disadvantage of this method is that it requires a high level of skill and experience. Because the marijuana plants react quickly, they are more susceptible to nutrient burn and lockout.

There are many different grow mediums available. A few examples include rockwool, vermiculite, expanded clay pebbles, perlite and coco coir, but there are many, many more on the market.

You can purchase many different types of commercial soilless mixes. Most combine two or more media in an attempt to produce an optimal growing mix.

Soilless media can be used in automated hydroponic setups or in hand-watered individual containers.

Growing marijuana indoors - hydroponics

Step 6: Choose containers for growing marijuana indoors

The container type you use to grow your cannabis plants depends on the medium you selected in the previous step.

If you are growing in super soil, 10 gallon nursery pots will be suitable to grow a few large plants, for example. If you chose a hydroponic system, the possibilities are many. For example a flood-and-drain, tray-style hydroponic system could use small net pots filled with clay pebbles or a large slab of rockwool.

The choice is yours and you can go as expensive or inexpensive as you like. Options range from disposable perforated plastic bags or cloth bags, to “smart pot” containers that are designed to enhance airflow to the plant’s root zone.

Many new growers choose five gallon buckets to grow their marijuana plants in when they are starting out.

Whatever containers you decide on, do make sure that they drain sufficiently. Drainage is crucial when growing marijuana indoors, because weed plants are very sensitive to water-logged conditions. Drill holes in the bottom of any re-purposed containers and set them in trays to ensure adequate drainage.

Growing marijuana indoors - nursery pots

Step 7: Choose essential nutrients for growing marijuana indoors

Cannabis flowers need more nutrients and fertilizer than most other plants.

Basic nutrients that are essential for growing marijuana indoors

Here is a list of primary nutrients (collectively known as macronutrients):

  • Nitrogen (N),
  • Phosphorus (P),
  • Potassium (K).

The following micronutrients are also beneficial, but you need far smaller quantities:

  • Calcium,
  • Magnesium,
  • Iron,
  • Copper.

Feed nutrients weekly to ensure plant health

You need to feed your plants a nutrient solution at least once a week, if you are not using a pre-fertilized organic soil mix.

You can purchase a nutrient mix in concentrated liquid or powder form. Both forms are designed to be blended with water.

Marijuana plants have different macronutrient needs during different stages of their life-cycles. Use the appropriate mix during the vegetative or flowering growth cycles. The different nutrient mixes are specifically formulated for the plants needs during that stage.

Marijuana plants require more nitrogen during vegetative growth, but more phosphorus and potassium during bud production.

Most macronutrients blends are available as two-part liquids, each in a separate container. This prevents precipitation which occurs when certain elements combine to form an inert solid that is unusable. You will need to blend the two bottles before use.

Feed additional nutrients if required

In addition than these basic nutrients, you may also need to feed your marijuana plants a calcium/magnesium supplement. Whether this will be required depends on the strain you are growing because some strains require more than others.

How to feed your marijuana plants nutrients

Once you have bought the necessary nutrient products, mix them with water as directed on the bottle, and then water your plants with the solution.

As a precaution, you can start out with a half-strength solution. Marijuana plants can be burnt fairly easily. As a rule of thumb remember that it is better to underfeed than overfeed. Start slowly until you learn to read the signs of your marijuana plants.

Step 8: Choose suitable water for growing marijuana indoors

Water is an essential element in the success of your cannabis grow.

Your water may not suit your cannabis plants

Never assume that your water is okay for your plants just because you can safely drink it. It may not be suitable for growing marijuana indoors.

Water, or rather what is in the water, can cause all kinds of issues for your marijuana plants. For example, if your water contains excessive amounts of dissolved minerals, they can cause a build-up in the root zone of the cannabis plants and affect the plant’s ability to absorb nutrients.  If the water contains fungus or other pathogens, this can lead to root disease. Just because the water is okay for you, doesn’t necessarily mean it is okay for your plants.

Chlorine levels in the water can also be a problem. High levels of chlorine can be harmful to beneficial soil microbes.

The easiest way to avoid potential problems is to filter your water, but this is only necessary if your water is potentially problematic.

Never overwater your marijuana plants

Overwatering is a common mistakes among novice weed growers.

Be careful not to overwater your cannabis plants. They are very prone to fungal root diseases when conditions are too wet.

How often you water your plants depends on the medium used, size of the plants and the ambient temperature. Some growers advise that you should wait until the lower leaves of the plant begin to droop slightly before watering.

Growing marijuana indoors - watering

Small marijuana beginnings can lead to luscious endings

This guide will give you a good start in your cannabis growing career. Where your journey will end is up to you. We wish you the best of luck!

As you grow in experience and knowledge, you can up your game! Increase the size of your grow room, upgrade your equipment, change growing techniques, or go professional. Anything is possible and everyone starts somewhere.

Happy cannabis growing and don’t forget to have fun!

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