Beginners Guide: How to Grow Weed Indoors and Harvest Potent Buds

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Looking to start growing cannabis indoors? Excited, but not sure how to grow weed indoors while getting the best quality out of your yield?

We can help you find out. The good news is that marijuana is a sturdy plant, and is able to withstand most beginners’ mistakes. It also doesn’t have to be expensive, as cannabis is able to adapt to most environments.

With the proper knowledge, inexperienced hobbyists shouldn’t have any trouble learning how to grow weed indoors. This guide contains the information you’ll need to create the most beautiful and potent buds at home.

From selecting your seeds to the harvesting process, we’ll cover all aspects.

Choosing Your Seeds

Before acquiring any equipment, you’ll need to select the strain of cannabis seed you’d like to grow. From cannabis indica, ruderalis, or sativa, many species are available, each producing different effects.

To know more about the difference between cannabis indica and sativa, this video may come in handy.

The best place to start might be with a strain you’re familiar with. One that produces satisfactory results for your particular needs.

For beginners, it’s preferable to start small, for a few reasons.

First, it’s less costly to acquire initial material — seeds and equipment — for a small number of plants. First-time growers often make mistakes that are fatal to the plant. Losing three plants will have a lesser impact on your wallet than losing 20 of them.

It’s also easier to keep a close eye on fewer plants. Monitoring cannabis — ensuring proper lighting, nutrients, and ventilation — can be time-consuming and requires constant supervision.

The Right Environment

Once you’ve selected your seeds, you’ll want to set up a suitable environment for optimum growth.

This environment can be either a grow room, a closet, a tent, or even a spare room. You’ll just need to adapt your equipment to the environment.

Choosing a Grow Medium

Most hobbyists tend to grow cannabis in organic or regular soil; however, a few other alternatives are available.

Regular Soil

More than the soil itself, the pH level and the number of nutrients present in the soil will greatly impact the growth of your weed. The texture of the soil is also important to consider, as it will affect water retention and drainage.

Many growers prefer organic soil as they’re more nutrient-rich. Some even make their own soil at home. Regular soil can also be mixed with other types of growing medium — such as coco coir — to combine the benefits.

Coco Coir

Coco coir uses coconut husks fibers. It promotes a fast growth, similar to hydroponic plants, and allows better absorption of moisture compared to regular soil.

Thanks to the light texture, nutrients are better absorbed. The quality of the material will make a significant difference when it comes to the roots’ growth.

For beginners, a 3:1 perlite ratio is recommended. For more experienced growers, a 1:1 perlite ratio will require more frequent watering, but gives more nutrients as well.

Deep Water Culture Hydroponics

Hydroponics cannabis is grown without the use of any soil. This grow medium normally means faster growth, as the roots don’t need to search for nutrients deep in the soil. The roots access nutrients directly from the water itself.

Because the plant isn’t spending as much energy on finding its food, it will spend that extra energy on expanding.

The seeds are first placed in a tube of water. Once your plant outgrows the tube, place it in a bubble bucket reservoir. To prevent the roots from rotting, it’s imperative to change the water in the reservoir on a weekly basis.

It’s best to grow one plant in each reservoir. A crowded environment will encourage the growth of mildew.

hydroponic setup


When considering how much space you’ll need to grow your cannabis, here are a few things to consider.

  • The number of plants or seeds you’re planting.
  • Allowing enough space for your plants to grow. At the start of the flowering stage, a cannabis plant can double or even triple its size. Confined, it won’t grow properly and might even suffer from a lack of light.
  • Setting up space for your equipment, such as lights, fans or reflectors.

Additionally, planning enough head space for your plants might be crucial when it comes to optimum growth.


You’re now aware that you’ll have to check up on your plants several times a day, or at least on a daily basis. For this, your grow room needs to be easily accessible.

Temperature and Moisture

When it comes to temperature, weed is a sturdy plant able to survive extremes. Some cannabis species — such as indica strains — will be able to handle high temperatures better than others.

For optimum growth, however, your grow room should stay between 70 and 85 degrees Fahrenheit with the lights on. When the lights are off, the temperature should range between 58 and 70 degrees Fahrenheit.

Too much moisture and your plants will create mold and mildew, and your buds might even rot. Not enough, and they’ll be struggling during the seedling and flowering phases. Ideal humidity levels should remain between 40 and 60 percent, up to the harvesting stage.

It is, however, recommended to lower humidity level to below 40 percent in the final weeks of blooming. For better control over humidity, try watering your plants after switching off the lights.

Temperature and moisture can be somewhat controlled with fans, heating mats, dehumidifiers or humidifiers, heaters, and air conditioners. Some lights can generate a considerable amount of heat, which can be helpful when growing weed in cold climates.

Note that all these devices require a fair amount of power, and can easily double your electricity bill. To avoid headaches on keeping your grow room environment under control, ensure ahead of time that it’s well insulated.



Cannabis needs CO2 — carbon dioxide — for photosynthesis, and therefore to survive and thrive. Access to CO2 is crucial to growing weed indoors.

Ideally, your grow room will have access to a constant flow of natural fresh air. It encourages growth, stronger stems, and limits the growth of pests and mold.

If a source of fresh air isn’t available, set up an exhaust fan above your plants, to remove warm air and to filter entering airflow. A supplemental CO2 system can be implemented, but would represent a significant investment for first-time growers.

If the smell during the blooming phase is an issue, a charcoal filter can be added to the exhaust.


Although cannabis is legal in many states, growers normally prefer to stay discreet. It’s important to keep in mind that fans can get noisy, and selecting a space that won’t attract unwanted attention is key.

Caring for Your Plant

Like any other plant, weed needs water to develop and thrive. It’s recommended to water your plants with compost tea or molasses, providing additional nutrients and encouraging its growth.

The water pH level is equally important. Cannabis is normally at its best with a pH ranging from 6.0 to 7.0 when planted. Hydroponic weed, however, prefers a pH between 5.5 and 6.5.

With lower or higher pH levels, the plant won’t be able to absorb the nutrients properly, weakening the plant. Water and soil should be tested regularly to ensure an adequate pH level.

Cannabis is also highly dependent on the quality and quantity of nutrients found in the soil. A soil rich in vitamins, compost, and living organisms should give your plants enough fuel for its entire life cycle.

For faster growth, fertilizers and mineral supplements can be added to the soil and water on a weekly basis. Nitrogen, phosphorus, potassium, calcium, and magnesium are considered the most important nutrients needed for high-quality marijuana.

Proper Lighting

Cannabis plants require a specific amount of daylight every 24 hours. The amount of daylight will differ, depending on the growth phase. We’ll elaborate on specific lighting needs later.

To avoid stressing your plants, set the same daylight timings every day. Darkness is also critical for marijuana’s growth, especially during the flowering stage. No light should leak in during dark periods.

Quantity and quality of your yield will largely rely on the quality of light provided. With the legalization of cannabis in many states, grow lights options have become plentiful.

When it comes to grow lights, it’s important to choose the best one your budget can afford. Here, we describe the most popular options.

High-Intensity Discharge Lamps (HID)

HID lamps are highly popular because of their efficiency and output. Although they can cost slightly more than fluorescent or incandescent lights, they generate more light with the same electricity consumption.

They might not be as efficient as LED lights, but also cost about 10 times less. You’ll find two main types of HID lamps.

  • Metal halide (MH) lamps are normally used during the vegetative phase and produce a blue/white light.
  • High-pressure sodium (HPS) lamps are very popular lamps, used during the flowering phase. They’re powerful and produce an orange/red light.

HID systems normally require reflectors or ballast to properly reflect the light throughout your canopy. If you need to choose between MH and HPS, HPS will generate more light per watt.

On the downside, HID lamps can generate a lot of heat, requiring exhaust fans, ducting, or air conditioners, to keep the temperature under control.

Fluorescent Grow Lights

Less expensive to acquire and set up, fluorescent lamps — specifically the high-output T5 lights — are very popular among beginners.

Most lights come as a complete package, with ballast, reflector, and bulb(s) included. They also don’t generate much heat, which is an important advantage, compared to HID lights.

Fluorescent lights, however, aren’t as efficient as other grow lights, and generate 20 to 30 percent less light per watt of electricity utilized. To equal the power of a 600-watt HPS lamp, you’d need 19 of the 4-foot long T5 lights.

This would require a tremendous amount of space. If you’re thinking to set up fluorescent lights, plan ahead!

To know more about fluorescent T5 lights, check out our dedicated article on these grow lights.

LED Grow Lights

Light emitting diode lights have been around for some time and are highly efficient. While they were known for their incredibly high cost, their popularity has made them more affordable. They still remain, however, much more expensive than an HID system.

LED lights are very sturdy and can last for years. They also consume very little electricity, therefore creating less heat than other grow lights. This doesn’t only lighten your electricity bill, it avoids additional expenses, such as fans or air conditioners.

led lights

Induction Grow Lights

Also called electrodeless fluorescent lights, these lamps were invented in the 1800s by Nicolas Tesla. They have been adapted to suit indoor growers. They’re pretty expensive, though, and not easy to find.

Grower-Friendly Tools

With many pieces to consider to create the optimum grow space, planting marijuana for the first time can be overwhelming. Here are a few tools to make the process easier.

Grow Tents

Grow tents are environments already set up with everything you might need to grow your cannabis. Some tents come with filters, lights, and fan included. The best ones even include separate vegetation and flowering chambers.

Just plug in the tent, place your plants, and you’re good to go.

Control Equipment

Growing weed is fun, but it also takes time. Not everyone can stay home all day, monitoring lightning, temperature, and humidity of their grow space.

Beginners might want to consider investing in three simple devices:

  • A timer to control lighting times.
  • A thermostat to turn on and off the exhaust fan(s). Set the device to the desired temperature. When your grow room exceeds that temperature, the fan turns on until it reaches a few degrees below the set temperature. This doesn’t only save time, but electricity as well.
  • A pH test kit is also recommended, to monitor your water and soil pH levels.

As you gain experience, more sophisticated devices can be purchased to control temperature, humidity, light, and even CO2 levels.

Growth Phases

Now that you’ve set up the ideal growth environment for your cannabis, let’s have a look at the different growth phases.

Seedling Phase

For beginners, this phase might be the most exciting. It’s fairly straightforward and could be set up in several ways.

  • Seeds can be placed on top of a moist paper towel. Cover the seeds, using a plate or plastic cup to keep humidity and moisture. Within a few days, you should be able to observe your seeds sprouting.
  • Plant trays or rock wool starters allow you to place up to 50 seeds together.
  • Seeds can also sprout when placed in nutrient-rich water, without any soil. After a week, you should see tiny roots appearing.
  • A germination station is a fancy seedling device, allowing a more controlled environment. Some even come with a heating mat, providing greater control over temperature and humidity.

This seedling phase ends when the first leaves are seen and photosynthesis starts. At this time, the baby plants can be placed in their final emplacement to continue their growth.

cannabis seedling just starting to sprout

Vegetative Phase

Proper lighting during the vegetative phase is vital. Cannabis should receive between 16 and 20 hours of light during a period of 24 hours. During the remaining four to six hours, your plants should remain in total darkness.

These hours don’t have to coincide with your day or night time. Sometimes, having the lights on during non-peak electricity times can significantly lower your bill. During this phase, CO2 can be added to boost growth.

During the vegetative growth, stems are flexible enough to allow “low stress training” or LST. This technique consists of bending the stem to give your plants a specific shape. A scrog can be used to ease this process.

LST can increase your yield and helps control the height of the plants, the “bushy look” being the most popular LST shape. Past this growth phase, the stem will be too rigid to allow safe bending.

To know more about LST, here is a useful video.

Blooming Phase

The blooming phase is characterized by the flowering of your cannabis plant, and a strong aroma develops. It usually lasts for eight to 10 weeks. Depending on the strain you’ve planted, the flowers might show a different shape and color — often orange, purple, or brown.

During this phase, you want to switch your lighting timer to 12 hours of light every 24-hour period. Without this lighting adjustment, your plants won’t bloom.

During this growth period, you’ll notice that instead of growing vertically and symmetrically, your plants start growing in a zig-zag shape. Soon, they’ll grow flowers with thicker leaves surrounding them.

Pistils are gradually covered with an abundance of trichomes, or fine hair. Slowly, the flowers will turn into a milky color, then amber.

If you’re looking for a high THC content, it’s best to harvest the buds when 20 to 30 percent of the trichomes have turned into an amber color.

If you’re aiming for a wider cannabinoid composition, harvest when 60 to 80 percent of the trichomes have turned amber. Keep a close eye on your plants, as you may only have 24 hours between these two harvesting stages.

marijuana flowering phase

Harvesting Phase

After the hard work, comes the reward. If your plants don’t exactly look as you expected, it’s okay. No one gets it right the first time, and what’s important is to learn from your mistakes and adapt your technique next time.

To trim your plants, there’s no right or wrong; it’s generally a matter of personal preference.

a dope bud ready to harvest

Trimming Wet

Trimming can be achieved using a variety of different techniques, which might differ, depending on the number of plants you’re growing.

Once ripened, cut the branches using trimming shears. Remove the leaves around the buds which are particularly high in THC content. This method is called “wet trimming.”

Dry Trimming

If you decide to use a “dry trimming” technique, let the plant dry out before trimming. Branches are then cut and hung in a drying room to dry further. This method is mainly used when you’ve got a large grow space and a short time to harvest your finished product.

Trimming Space

During the blooming phase, the cannabis smell can be quite strong. While harvesting, aromas will take it to the next level. Make sure that your trimming space is well-ventilated. It could be your grow room, if space allows, or any other suitable room.

It’s important to consider non-smokers. Odors travel fast and are strong. Smokers are normally used to it and appreciate the fresh smell of marijuana. Non-smokers, however, might find the smell unpleasant, and the last thing you need is a fight with the neighbors.

Drying Room

Your work isn’t quite done yet; 75 percent of the water contained in your buds now needs to be removed. This step is very important and shouldn’t be overlooked. After months of intensive care and love, you wouldn’t want to see mold appear on your precious buds.

Placing your buds in a microwave to hasten the process will result in a less potent bud with a bad taste. Instead, place your buds in a dark and cool room, anywhere from 59 to 71 degrees Fahrenheit.

The smallest buds should be dry within a week, however, the larger ones might take up to two weeks. If you’re limited with time, you can break down the largest buds to speed up the process.

Proper ventilation is key. It’s best to hang them because laying them flat on a piece of newspaper will limit airflow. Drying racks can be purchased to save space.

storing cannabis buds in a air tight jar

Is My Cannabis Ready?

Try breaking a large bud’s twig. If it detaches easily, your bud is dry and ready to be consumed.

Ensure that all buds are dried properly. By mixing moist buds with dry ones, your dry buds will absorb some of the moisture.

Light damages THC. Make sure to keep your finished product in a dark container — plastic or glass — away from sunlight. Keep it stored in a cool place.


Growing cannabis is an art and can take time to fully master. Cannabis for recreational or medical use has now been legalized in a number of states. Why purchase it in a dispensary when you can make your own at home?

First-time growers shouldn’t be discouraged by mistakes; the yield will improve with experience. Now you know how to grow weed indoors isn’t complicated, following our comprehensive guide should allow you to produce potent, tasty buds.

Are you growing cannabis at home? Is this your first time? Please tell us how it went, we look forward to your feedback!

pic of a marijuana plant just starting to flower

Photo of author


Meet Edward, the passionate gardener turned cannabis enthusiast who is dedicated to exploring different strains and maximizing their yields. With his background as a hydroponic agriculture technician, he brings a unique perspective to the world of cannabis cultivation. As the head field tester at HempGrowly, he shares his technical expertise and insights to help readers achieve their own successful hydroponic grows. Through his easy-to-follow documentation of his findings, Edward hopes to help cannabis growers of all levels achieve maximum yields and enjoy the benefits of this amazing plant.