The Ultimate Guide to Growing Cannabis Indoors

Growing marijuana indoors has become increasingly popular among many users whether recreational or medicinal. Cultivating your own cannabis offers many benefits and opportunities for customization. 

However, there are some issues if you want to grow your own cannabis. From prying eyes to erratic weather, there are many things to think about. 

So what do you do? Well, you cultivate cannabis indoors! 

In this guide, we'll walk you through the step-by-step process of cannabis cultivation from setting up your growing space to harvesting top-quality buds.

Growing cannabis indoors gives you immense control over the growing environment, ensuring consistent conditions throughout the plant's life cycle. By managing factors like light, temperature, humidity, and nutrients, indoor growers can produce high-quality cannabis all year round regardless of external weather conditions.

Let's find out how to cultivate cannabis indoors, shall we? This guide will help even if you're an absolute beginner. 

Advantages of Indoor Cannabis Cultivation

Indoor cannabis growing comes with a host of benefits that make it an appealing choice for both hobbyists and commercial growers. Here are some key perks:

• Cultivate throughout the year

If you grow outdoors, you're bound by limitations, but indoor growing allows you to cultivate throughout the year regardless of the weather outside. This means you can have cannabis whenever you desire, without waiting for the next outdoor harvest.

• Total Environmental Management

Indoor growers have control over every aspect of the growing environment, from lighting and temperature to humidity and airflow. This control empowers growers to create the best conditions for growth leading to healthier plants, quicker development, and increased yields.

• Privacy and Discretion

Indoor cannabis cultivation offers a level of privacy and discretion that outdoor growing cannot match. With a proper setup, you can grow cannabis discreetly at home without attracting attention from neighbors or passersby. This is especially advantageous in regions where cannabis cultivation may not be fully legal yet or for those who prefer to keep their growing activities a secret. 

• Personalization and Experimentation

Indoor growing offers a range of customization and experimentation possibilities. From selecting the growing medium to trying out various cultivation methods, indoor growers have the freedom to create a growing space that meets their specific preferences and objectives. Whether your focus is on maximizing yields, potency, or terpene profiles, indoor cultivation allows for flexibility in exploring and honing your skills.

• Enhanced Quality

By controlling the conditions indoors, you can achieve better yields and higher quality buds compared to outdoor growing. You can even grow in such a way that you get denser buds, robust flavors, and elevated levels of THC and other cannabinoids.

• Pest and Disease Management

Indoor cultivation helps reduce the likelihood of pests and diseases that commonly affect marijuana plants. By bringing your plants inside your home, you can effectively manage pests like spider mites, aphids, and whiteflies while also preventing diseases such as powdery mildew and bud rot. This approach helps reduce the reliance on pesticides and ensures that your plants remain healthy and free of pests.

• Convenience and Accessibility

Growing cannabis indoors offers accessibility and convenience, particularly for individuals with limited outdoor space or those residing in urban areas. With a small indoor grow tent or a dedicated grow room, you can cultivate cannabis in your home, whether it's an apartment, condo, or house.

• Consistency and Predictability

Indoor cultivation provides a level of consistency and predictability when it comes to harvests and quality. By controlling factors like light cycles and nutrient levels, you can be successful in harvesting a consistent supply of high-quality cannabis.

Setting Up Your Indoor Growing Space

Establishing your growing space is the primary step toward successful cannabis cultivation. Whether you opt for a room, closet, or dedicated grow tent, creating an ideal environment is essential for promoting healthy plant growth and maximizing yields.

• Space

Make sure you have ample room for your plants to thrive as they develop. A spare room is ideal whereas smaller areas can make use of grow tents.

• Accessibility

Opt for a spot that's easy to reach for tasks, like watering, trimming, and checking on your plants.

• Ventilation 

Make sure the area has enough airflow to regulate temperature and humidity. Having windows or a ventilation system for air circulation is essential.

• Privacy

If secrecy is a concern, pick a location that provides privacy and limits exposure to outsiders.

Setting up Your Grow Tent

After selecting your spot, it's time to plan out your growing area. Here are some important factors to consider:

• Setup

First, set up your grow tent according to the instructions from the manufacturer. Of course, you can make a DIY grow tent but that's a topic for another day. We have covered this topic too, and you can read about it here. 

• Light Proofing

Make sure your grow tent is completely sealed off from any light sources as this will be critical during the flowering stage. 

• Ventilation

Set up exhaust fans and intake vents in the tent to keep air circulating and prevent overheating. Using carbon filters can help control any odors.

• Reflective Surfaces

Line the walls of your growing area with reflective materials like Mylar or white paint to optimize distribution and reduce hot spots.

• Waterproofing

Use materials such as plastic trays or waterproof paint to protect floors and walls from water damage.

• Electrical Outlets

Ensure there are outlets available to power all your grow lights, fans, and other necessary equipment.

Important Equipment 

Since you're growing indoors, you will need to mimic the conditions outdoors. For this, you'll need some equipment, including:

• Grow Lights

Opt for grow lights that suit your area and budget like LED, HID, or fluorescent lights. Take into account the light spectrum, intensity, and coverage range.

• Ventilation System

Set up exhaust fans, intake vents, and ducting to uphold airflow and regulate temperature and humidity levels.

• Grow Medium

Pick a grow medium that matches your cultivation approach such as soil or coco coir for hydroponics.

• Containers

Pick pots or containers that offer drainage and room for root growth. You can even go for air pots or fabric pots for enhanced root growth. 

• Nutrients

Select top-notch nutrients designed specifically to cultivate cannabis. Most growers use commercially bottled nutrients that are designed to grow plants in both the vegetative and flowering phases. 

• pH Meter and pH Adjusters

The pH is the most important aspect you need to consider when growing cannabis. Granted, pH strips are much cheaper but they are inaccurate so always go for digital pH meters. Keep an eye on the pH of your solution and make adjustments as necessary when you start growing the plants. 

• Thermometer and Hygrometer

Measure the temperature and humidity levels to create a good environment for the plants. 

• Pruning Shears and Scissors

Use sanitized tools for pruning, trimming, and harvesting the buds. 

• Timer

Arrange timers to manage light during the vegetative and flowering phase. 

• Training Equipment 

When you're setting up your garden, think about using trellis nets, stakes, or plant ties to help train and support your plants. 

Choosing between Seeds and Clones

Selecting cannabis seeds or clones is a decision that can greatly influence the outcome of your indoor growing venture. Understanding the distinctions between seeds and clones along with the diverse seed varieties will help you make better decisions that align with your cultivation preferences. 

Types of Cannabis Seeds

There are hundreds of not thousands of cannabis strains available today. Each strain is unique and has various characteristics in terms of growth patterns, cannabinoid compositions, flavors, and scents. 

Here are some common types you may come across:

• Indica

Strains predominantly leaning towards Indica typically produce bushy, short plants with thick buds. Such strains are best to use at night as they may have some sedative properties. 

• Sativa

Strains leaning towards Sativa generally produce plants with airy buds. They are renowned for their invigorating and mood-enhancing properties, making them popular selections for daytime enjoyment.

• Hybrid Varieties

Hybrids are created by crossing indica and sativa plants to blend the qualities of both types. They can lean towards indica, or sativa or strike a balance between the two, offering an array of effects and flavors.

• Photoperiod strains

Photoperiod strains are those that rely on the light cycle to start flowering. Typically, you'll provide 18 hours of light and 6 hours of darkness during the vegetative stage. Once the plant has grown satisfactorily, you can switch to 12 hours of light and 12 hours of darkness to trigger flowering. 

• Autoflowering strains

Autoflowers are those that don't rely on the light cycle like photoperiod. Thus, even if you don't switch the light cycle from 18/6 to 12/12, the plants will flower after they attain a specific age or about 4-6 weeks after germination. 

• Feminized Seeds

Feminized seeds exclusively produce only female plants, thereby eliminating the need to identify and remove males to prevent pollination.

Setting Up an Optimal Growing Space

To promote the growth and well-being of cannabis plants, it's crucial to establish a good growing environment. Otherwise, everything is for naught, even if you have the best seeds in the world. 

This involves managing light, temperature, humidity, and airflow to simulate conditions the plants experience outdoors. Below are tips on optimizing each element in your indoor cultivation area:

Lighting Needs

Light is super important for plants as they use it for photosynthesis and to make food. Thus, it's important to provide the right intensity that sustains plant development.

Cannabis plants thrive on high-intensity light to support growth and flower formation. Use grow lights like LED or HID lights to ensure adequate intensity throughout all growth stages.

Also, keep in mind that the light spectrum matters as the plants need different light spectrums depending on their stages of growth. For example, during the vegetative or growing stage, they will need light in the range of 400 to 500 nanometers, which supports their growth and helps develop sturdy stems. As they enter the flowering stage, plants need light spanning from 600 to 700 nanometers to encourage flower production and increase yields. This means that they need blue light for the vegetative and red light during the flowering stages. 

We have already mentioned the light cycles. Remember that it's important to follow an 18/6 during the vegetative stage and 12/12 during the flowering phase if you're growing photoperiods. 

In addition, to ensure proper coverage over the plant canopy, position grow lights at an appropriate height and angle. Adjust the intensity and placement of lights as the plants grow to prevent issues like a light burn or excessive stretching.

Temperature and Humidity Management

Maintaining appropriate temperature and humidity levels is essential for promoting cannabis growth and avoiding problems such as mold, mildew, or nutrient deficiencies. 

Cannabis plants thrive in temperatures ranging from 70-85°F (21-29°C) during the day with slightly lower temperatures at night. Avoid drastic fluctuations in temperature as they can stress plants and impact their development.

Coming to the humidity, you need to adjust it according to the stage of plant growth. During the vegetative stage, it's ideal to maintain the levels between 40-70%. As your plants transition into the flowering stage, aim for a humidity range of 40-50% to prevent issues like mold and bud rot. You can use either humidifiers or dehumidifiers to keep humidity levels in check.

Ventilation 

Efficient air circulation is key for supplying plants with CO2, dissipating heat, and averting the accumulation of still air. Here are some tips for ensuring air circulation and ventilation:

• Exhaust Setup

Position exhaust fans strategically to expel stale air from your growing space and direct it outdoors. Placing these fans near the top of the grow area aids in removing heat and moisture.

• Intake Arrangement

You can use intake fans to draw external air into your grow space. Make sure you position the vents at the bottom of your grow tent to guarantee a continuous influx of fresh air.

• Using Oscillating Fans

To enhance air circulation and prevent pockets of hot air, position oscillating fans within the growing area. However, the air shouldn't blow on the plants directly or there could be wind damage. 

Selecting the Right Growing Medium

Choosing a good growing medium is essential for providing your cannabis plants with support, nutrients, and oxygen for optimal growth. When it comes to cannabis cultivation, soil and hydroponics are the most common options and they both have their own advantages and disadvantages along with unique care requirements. You can go with either of the two, depending on what you're comfortable with. 

Although soil is slightly more forgiving and good for beginners, hydroponics offers more precision. You can either make your own soil mix using organic ingredients or purchase a premade soil mix for the best results. Similarly, you can construct your own hydroponics setup or purchase one. 

How to Grow Cannabis Indoors

Now that you understand the basics and how you need to prepare before you start growing the plants, let's start with step-by-step methods explaining everything in detail. 

Seed Germination Methods

Germination is the process in which a seed sprouts to kickstart plant growth. Here are some popular germination methods:

• Paper Towel Method

Place cannabis seeds between paper towels. Ensure the towels stay moist but not excessively wet. Keep the setup in a warm and dark spot. Leave the towels undisturbed. Once you see taproots popping out, transfer the seeds to your preferred growing medium. 

• Direct Planting

Plant cannabis seeds directly into a pot with the growing medium. The medium should drain well while retaining moisture. Maintain adequate warmth and moisture (around 70-85°F or 21-29°C). Expect germination within a few days to a week.

• Seedling Starter Cubes

Utilize seedling cubes crafted from materials like rockwool peat moss or coco coir. Soak the cubes in water for at least 24 hours or according to the manufacturer's instructions. Next, squeeze out excess water and insert cannabis seeds directly into them. 

Make sure to keep the cubes damp and at a consistently warm temperature until the young plants start to sprout. 

If you choose to use clones, you can either take a cutting from a friend or purchase it from a nursery that sells cannabis clones. Or, you can make some clones on your own if you have a cannabis plant. 

• Preparing the Planting Mix

Fill pots or containers with a well-draining, nutrient-rich planting mix. For clones, make sure the rooting mix is damp but not soaked.

Seedling stage

Carefully make a ¼ inch hole and plant the seeds in the potting mix. Spray the soil with some water, wait for a few days, and you'll see the cotyledons appear. Cotyledons are the first two leaves that sprout. They contain enough nutrition for the seedling to survive for a couple of weeks so you don't need to provide any nutrition at this point. 

Use a fan on its lowest setting to softly blow air into the tent. Using a humidity dome or clear plastic cover is optional but it can help maintain perfect humidity levels around seedlings. Remember to remove the dome once every two days to allow air in and prevent mold growth.

Now all you need to do is wait until the seedling grows at least a couple sets of leaves, which can take about 1-2 weeks depending on the strain, growing medium, and the environment. 

As far as watering is concerned, make sure you are very gentle and don't disturb the roots. A spray bottle will work wonders here. In addition, don't water randomly. Instead, water only when you see the top soil dry. Overwatering at this stage can cause damping off. 

The seedlings will need at least 18 hours of light and 6 hours of darkness but don't use lights with high intensity right away. You can go with fluorescent or CFL lights. If you're using strong LED lights, make sure there's at least 20-24 inches distance between the lights and the plants. Adjust the lights according to the growth so they don't receive too much or too little light. If they get less light, they may become lanky whereas too much light can burn them. 

Once the seedlings have a couple of sets of leaves, you can start feeding nutrients. Start with quarter-strength nutrients designed for the vegetative stage. Increase the strength slowly every week as the plant grows. 

Once the seedlings have developed 5-6 sets of their true leaves and are strong enough, you can transplant them into larger containers if necessary. Be gentle when handling the seedlings by holding them by their leaves or root balls to avoid harming the roots.

The new container you're transplanting to should have the same potting mix or the seedlings will have trouble adjusting to their new environment. Make sure the soil is moist when transplanting. Some growers like to transplant the plants again just before the flowering stage but you can directly transplant it into the final container right away. Water the plants thoroughly after transplanting to help the soil settle around the roots. 

Keep an eye on your seedlings for signs of stress, pests, or nutrient deficiencies. Also, remove any dying or yellowing leaves. Adjust growing conditions as needed to promote growth.

By providing the right environment, light, water, and nutrients during the seedling stage you will set the foundation for your cannabis for better growth and development throughout their life cycle. Before we continue, it’s important to understand the pH, as it’s one of the most important factors in growing cannabis. 

pH for Soil and Hydroponic Systems

Maintaining the right pH is important whether you’re growing in soil or hydroponic systems. If the pH isn’t in the right range, then your plant will be unable to absorb nutrients and experience a variety of nutrient deficiencies. If you’re growing in soil, the pH needs to be between 6 to 7 for optimum absorption. For hydroponic plants, the pH needs to be between 5.5 to 6.5 for best results. 

To adjust the pH in soil, you can use dolomite lime to raise the pH while phosphoric or citric acid will reduce the levels. For hydroponics, use pH Up to increase the pH while pH Down will work to decrease the levels. While adjusting the pH, make sure you do it gradually and retest the pH after waiting for at least 20-30 minutes. Do not increase or decrease the pH suddenly as it may shock your plants. 

Vegetative Stage

This is a crucial period for your cannabis plants. During this stage, plants focus on growing their stems, leaves, and roots to prepare for the flowering phase where they will start producing buds. Taking care of plants and managing them properly during this phase is crucial for ensuring healthy growth and strong plants. 

• Light Cycles

Light cycles play a major role in regulating the growth of cannabis plants. In their vegetative stage, plants need certain periods of light to promote growth. The typical light cycle during the phase involves 18 to 24 hours of light followed by 6 or 0 hours of darkness. 

Most growers provide 18 hours of light, but some go with 24 hours of light to prompt explosive growth. However, this is somewhat unnecessary and may even harm the plants as they also need to rest a bit during the darkness period and start afresh the next day. On the other hand, longer periods of light boost photosynthesis and foster rapid development of leaves and stems. Thus, you can provide 24/0 light for a few days and continue with the 18/6 cycle once you're satisfied with the growth. 

• Light Intensity

Maintain high-intensity lighting throughout the growing or vegetative stage to ensure excellent growth. Use grow lights like LEDs, MH (Metal Halide), or T5 fluorescent lights positioned at an appropriate distance from the plants.

Cannabis plants thrive best under full-spectrum light with a mix of blue and white wavelengths during their vegetative stage. Although it's not as important as the flowering stage, maintain complete darkness during the dark period (6 hours) to avoid disturbing the plant's metabolic processes.

• Nutrition 

Proper nutrition is key for growth during this stage and requires a balance of macronutrients like nitrogen, phosphorus, and potassium as well as essential micronutrients. Nitrogen is especially vital for foliage growth while phosphorus and potassium support root development and overall plant health. Don't forget about calcium and magnesium too. They're crucial for growth.

Micronutrients, like Iron (Fe) manganese (Mn) zinc (Zn), and other essential micronutrients play a role in supporting metabolic processes in cannabis plants. It's important to provide a solution or supplement with micronutrients as needed to ensure healthy growth. As a beginner, it can be tough to supplement micronutrients in an isolated manner as you'll need to calculate the exact ratios to prevent an imbalance. Therefore, stick to the commercial nutrient solutions and follow the manufacturer's instructions. 

In any case, it's best to purchase commercially bottled nutrients as it makes it easy to feed the plants. Typically, you'll get three parts of nutrients including the vegetative stage, flowering stage, and micronutrients. You'll need to mix the “Grow” or nutrients meant for the vegetative stage along with the micronutrients and feed them to the plants. Always stick to a proper regimen rather than watering the plants whenever you wish. 

Coming to supplements, you can use fish emulsion or aged cow manure to provide some more nitrogen. Even chicken manure will do wonders. If not, just purchase nitrogen supplements but don't go overboard. 

Training 

Although training your plants is optional, you can do it if you want to increase the yields. Typically, cannabis plants grow like a Christmas tree where they have just one main cola. However, you can improve the yields by forcing the plant to produce more colas. You should also remember to train the plants only during the vegetative stage to ensure the plants get some benefits. Doing it during the flowering stage can stress the plants and reduce yields. 

In short, training techniques are used to shape the plant's structure, encourage growth, and enhance overall yields. Here are some common techniques:

• Topping

This technique involves cutting off the tip of the stem to stimulate the growth of colas (top buds) promoting bushier growth and increasing potential bud sites.

• FIMming (F*ck I Missed)

Similar to Topping, FIMming entails removing only a part of the main stem’s tip to encourage lateral branching and potentially boost yields.

• LST (Low Stress Training)

By bending and securing branches to the sides of the container, LST helps create a uniform canopy and exposes the lower bud sites to light for optimal light penetration and uniform growth.

• Defoliation

Removing excess foliage, especially large fan leaves that obstruct light from reaching lower bud sites, can enhance airflow and light exposure for improved bud development.

These techniques are essential for maximizing plant health and yield potential during the growing process. During the growing phase, it's crucial to observe plant growth and make adjustments in lighting, nutrients, and training methods as necessary. If you nail this phase, you're well on your way to getting amazing yields. 

Flowering Phase

The flowering period marks the shift of cannabis plants from growth to flower (bud) formation. This stage is pivotal to achieving a harvest of top-notch cannabis. To do this, you'll need to understand how to manipulate the plants so they think it's time to flower and start developing buds. 

• Transitioning to Flowering

To kickstart the flowering process, cannabis plants need a shift in their cycle to mimic short days and longer nights akin to autumn. To do this, move from the 18/6 cycle to the 12/12 flowering light cycle (12 hours of light followed by 12 hours of darkness). This alteration signals to the plants that it's time for them to begin blooming. You're essentially imitating the natural lighting changes that occur as autumn approaches for cannabis plants.

• Light Sealing

Ensure that your growing area is completely sealed from any light during this period to prevent disruptions in the flowering process.

To prevent any light leaks you can use curtains, light traps or light-proof grow tents. This is crucial because even small light leaks can interfere with the flowering process. The plants can be so stressed that they revert back to the vegetative stage, also known as revegging. The plants may also start developing seeds, also known as hermaphroditism. Since you're growing cannabis to get seedless or sensimilla buds, it's important to prevent light leaks. 

Remember to be patient after switching to the flowering light cycle as it might take 1-2 weeks for the plants to start flowering. Keep an eye on your plants during this time.

Now, stick to the 12/12 light cycle throughout the flowering stage to avoid stressing out your plants. This is important for optimal bud growth and resin production. 

• Light Spectrum

Use quality grow lights that emit the right spectrum of red and orange wavelengths during the flowering stage. Red light encourages flowering and resin production. 

You don't need to do anything special when it comes to the spectrum. Just make sure you get a full-spectrum light. LEDs work fantastic and are ideal to be used throughout the plant’s life cycle. You can also use HID lights but while MH lights are good during the vegetative stage, HPS lights should be used during the flowering stage. 

In any case, only use lights that have high-intensity lighting during the flowering stage to support bud development. To avoid burning the plants from extreme light exposure and to ensure optimal light absorption, adjust the height of your grow lights above the canopy. 

• Nutrient Requirements 

When cannabis plants transition into the flowering stage, their nutrient needs are slightly different from the vegetative stage. Here's a breakdown of what you should consider for management during flowering:

Decrease Nitrogen Levels

It's essential to lower nitrogen content in your solution or soil mixture as high nitrogen levels can hinder bud growth and promote excessive leaf development. This means that you should use the “Bloom” part, or the nutrients meant for the flowering stage along with the micronutrients, and feed them to the plants. 

Boost Phosphorus and Potassium Levels

Increase phosphorus (P) and potassium (K) levels to promote flower development and resin production which are crucial for blooming stages.

Include Macronutrients and Micronutrients

Make sure your plants receive calcium (Ca) magnesium (Mg) iron (Fe) and zinc (Zn) along with other micronutrients during flowering for healthy growth.

Enhance Blooming with Supplements

Consider adding bloom boosters or specialized flower additives to improve bud formation, resin yield, and terpene content in your plants.

Monitor pH and EC Levels

Regularly check the pH and electrical conductivity (EC) of your solution to ensure nutrient absorption by the plants. Adjust pH levels as necessary to maintain an environment ideally between 5.5 to 6.5 for hydroponic plants and 6 to 7 for those in soil. 

And, that’s about it. The flowering period will depend on the specific strain you’re growing, but these are the basics of growing cannabis indoors. You will be able to harvest once the plants are mature. Then comes the drying and curing process. Hopefully, this guide will help you start growing cannabis. 

Summary: The Ultimate Guide to Growing Cannabis Indoors

As you can understand, growing cannabis indoors is pretty easy if you understand the basics. If you take care of the pH, and environmental conditions including the temperature, humidity, airflow, and light, you’ll be able to harvest incredible yields if your chosen strain is genetically predisposed to producing good yields. 

We hope you start growing cannabis today!