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Quick Guide to Growing Cannabis Indoors for Beginners

As cannabis legalization is progressing around the world, many cannabis users are looking at whether or not growing their own plants at home is right for them. Before attempting home growing, it’s crucial to have the space, the right environment, and knowledge about cultivation. In this guide, we’ll walk you through the basics of growing your own cannabis indoors.


Benefits to Growing Cannabis Indoors

There are many benefits to growing cannabis in general. Here are some of the top reasons why patients and consumers chose to grow their own cannabis even in markets where dispensary access is abundant.

Quality Control

One thing that many personal growers really enjoy about cultivating cannabis at home is their ability to know precisely what their medicine has been exposed to. Unfortunately, many large commercial grows require the use of pesticides, herbicides, and other chemicals. When you are growing your own cannabis, you get to choose how you control pests and what type of nutrients you feed your plants. For many people, this provides peace of mind that what they are consuming is safe and of the highest purity.

Growing Your Own Lets You Save

Aside from the cost of the initial setup to grow at home, in the long run growing cannabis at home will likely save you a lot of money. If you are someone who seldomly consumes, growing is probably not the most cost-effective. However, if you are a medical cannabis patient or a recreational consumer that utilizes a lot of cannabis regularly, growing at home could save you thousands of dollars each year.

You’ll Have More Choices

For many consumers and patients alike, there are specific strains of Indica or Sativa that we enjoy consistently or that always seem to provide relief. Unfortunately, sometimes finding that particular strain regularly is easier said than done. Growing at home can open up your options to specific strains, and there are seed banks and dispensaries across the country that provide genetics to home growers.

Growing Is Therapeutic

The love and care that cannabis plants desire is another reason why many people enjoy growing at home. It can be very therapeutic to nurture a plant throughout its lifespan. Growing is also a great way to connect with nature, and after all, it’s always fun to get your hands a little dirty!

Indoors Cultivation Offers Minimal Risks

There are some advantages to indoor growing in comparison to outdoor cultivation. In outdoor environments, it is much easier to maintain light and moisture as mother nature takes care of most of it. However, outdoors plants are susceptible to various pests and environmental risks—like spiders, aphids, and other creepy-crawly bugs—as well as animals that munch on cannabis leaves, like deer and rabbits. These risks can be prevented much easier in an indoor setting.

Common Growing Mistakes to Avoid

Before you get started on your first grow, let’s go over some of the most common growing mistakes to avoid.

Giving Your Growing Plants Too Much or Not Enough Nutrients

Giving your plants too many nutrients, sometimes referred to as overfeeding, can be a very easy mistake to make, especially since it may not be your fault. It has been found that most nutrient companies are recommending feeding schedules that are too high. Complying with the feeding schedules can overfeed your plant and cause more harm than good. More food does not mean more goods. Read more about common nutrient issues here.

Overwatering or Underwatering Your Plants

Over and underwatering are both common mistakes, although overwatering the plant happens more commonly. Both can be detrimental to your plant, but both are easy to fix. An overwatered cannabis plant will have leaves that are drooping but are firm to touch, whereas an underwatered cannabis plant will have leaves that are limp and brittle.

Incorrect Climate Conditions

Proper temperature and humidity are crucial to the growth and development of high-quality cannabis. The most common mistake people make is not being fully aware of the climate the plants are growing in. Temperatures that are too cold can stunt plant growth and can even kill the plants in more extreme cases. If the temperature is too hot, it will cause the plant to stress, which can lead to curling leaves, very bad buds, and it can also kill the plants in extreme cases.

The Wrong Lighting

Not having enough lighting for the plants is a common problem for indoor growers. When growing outdoors, common mistakes include positioning the plant with insufficient sunlight coverage, placing the plants too close to light sources, or exposing the plants to light for too long of periods, causing light burn.

Harvesting Your Grow at the Wrong Time

With regards to harvesting, common mistakes include doing so too early or too late. This can result in reduced effects from the cannabinoids of the plant and minimizing the medicinal and recreational effectiveness. Harvesting needs to be done at the right time to avoid losing potency as well as to avoid extreme cases such as rotting.

Basic Supplies Needed to Set Up a Grow Operation

Some of the things you will need to set up a grow operation at home include lights, grow containers, seeds or clones, a thermometer, a CO2 monitor, a humidity monitor, timers, nutrients, and most of all, patience.

  • Lights: When it comes to choosing the best lights to grow weed indoors, it will all depend on your specific setup. For most home growers, LED grow lights are the preferred choice, because they offer the full spectrum of light needed for cultivation while utilizing less electricity. Other lighting options include MH (metal halide), HPS (high-pressure sodium), HID (high-intensity discharge), etc.
  • Grow Containers: Grow containers are essential for marijuana growing at home as they will hold your grow medium and the plant throughout its various growth cycles. There are various types of grow containers including plastic, fabric, and even cement/stone varieties. The most commonly utilized however are plastic and fabric pots. Both of these come in a variety of sizes ranging from 1-20 gallon pots on average.
  • Seeds or Clones: Cannabis seeds or clones are needed to get started. In many places where cannabis has been legalized, home growers are able to choose from a wide variety of seed and clone genetics at their local dispensaries or grow supply stores.
  • Thermometers and Other Monitors: You must pay close attention to the temperature and humidity in your grow environment at all times. Additionally, ensuring that your marijuana plants are growing in a balanced pH environment with the optimal CO2 is crucial. Thermometers along with humidity, CO2, and pH monitors are all essential to monitor your plants’ environment. You may decide to use a humidifier or dehumidifier.
  • Scissors: Scissors are essential for harvesting and trimming grown marijuana plants. Scissors are also useful during the growth process when completing defoliation (leaf removal).
  • Timers: Timers, or lights that have timers, are essential because you, as the cultivator, are responsible for mimicking the light cycle that your plants grow under. This means that at different stages, your lights should automatically go off and on at certain intervals. Having a timer makes this easy so that you are not required to do it manually each day.
  • Nutrients: When cultivating indoors, it is essential that you provide your plants with certain nutrients to help them grow better. Nutrient solutions can also be vital to the overall flavor, effects, and yield of your cannabis grow.
  • Microscope: A microscope will be beneficial for various reasons including monitoring your plants for microscopic pests as well as determining whether your trichomes are at the optimal stage for harvesting your plants.


Best Place to Grow Cannabis at Home

Some of the most common places where people grow cannabis at home include a closet, spare room, bathroom, grow boxes, or tents. Let’s take a closer look at the advantages and disadvantages of each grow space.

Closet

While closets are convenient, they aren’t always the best grow room; it is difficult to tend to your plants in such a small space with access from only one side. It is also difficult to prevent light leaks as there are many ventilation issues that could lead to heat buildup, humidity issues, and light issues. If growing in a closet is your only option, though, go for it. It is advised, however, that this environment likely will not produce the best results.

An Extra Room

Turning an extra room in your home into a grow room can be a great idea, but it can also present some issues. Growing in the open within a large area can make controlling aspects such as your lighting, humidity, temperatures, and fresh air intake challenging.

Bathroom

Bathrooms are not ideal grow rooms. The amount of moisture in a bathroom is almost guaranteed to cause issues with mold and mildew. Not to mention that the excessive amount of moisture will also present a constant battle for you while trying to control humidity. Unless it is the only space you have, it is highly advised not to cultivate in a bathroom.

Grow Box

In recent years, grow tents have become one of the favorite growing areas for at-home cultivators. Grow boxes are a much more superior option for cultivating cannabis in comparison to growing it in a closet, an extra bedroom, or a bathroom. Grow boxes fully enclose the grow environment to help cultivators better maintain optimal conditions. However, they can be quite expensive and difficult to relocate.

Grow Tent

Grow tents are self-enclosed tents for cultivating cannabis. They are often prefabricated with areas to hang lighting, introduce airflow, and additional storage for monitors and other tools. Grow tents have become the go-to choice due to their ease of use, efficiency, and availability. Many grow tents offer a reflective interior to make the best use of your lighting. While rather expensive, they are one of the best choices, and many patients and consumers choose to make the investment.

Which Method to Choose: Soil Growing vs. Hydroponics

Let’s look at the benefits of the two different growing methods: soil growing vs hydroponics.

Soil

Soil is a popular growing medium for first-time growers, because it is cheap, easy-to-use, and is plenty forgiving. You can even buy pre-fertilized soil (our recommendation) so you won’t need to worry about adding any nutrients to your soil. If you are feeling adventurous, you can use regular soil and add nutrients as you go.

Hydroponics

Hydroponic systems are popular because they do not require soil. It is cleaner in that sense, and it can provide big yields if done right. Plus, plant growth is often faster when hydroponically grown.

There are a variety of grow materials to consider when using hydroponics:

  • Clay pebbles
  • Coco coir
  • Vermiculite
  • Rockwool

Each material can be found for a decent price, and there are often mixes of two or more of these materials that can be bought as soilless mixes that make getting started with hydroponic growing that much easier.

Growing Variables to Consider

Let’s discuss some of the most important variables to consider when cultivating cannabis at home and why controlling these variables is essential to the success of your grow.

Lighting

Cannabis grows with the cycle of the sun. This means that during the various stages of growth (which we’ll go over in the next section), the plant requires different amounts of light.

During the vegetative growth stage, your plants will crave light and should be exposed to light for a minimum of 16 hours each day, followed by 8 hours of darkness. When your plants are ready to enter the flowering stage, where they will begin to produce buds, you will need to mimic the changing of the seasons and reduce the light cycle to 12 hours of light and 12 consecutive hours of dark. Not controlling your lighting can cause detrimental harm to your plants, including stunted growth, hermaphrodites, mold, and powdery mildew.

Smell

For many years, trying to control the smell of cannabis was one of the hardest things cultivators had to do. Today, however, many individuals live where they are able to cultivate cannabis legally, and smell is not quite as big of a concern. If you live in an apartment, it is likely you will want to keep the smell of your grow under control as much as possible. The most highly recommended solution and the only sure way to eliminate all smells is to install a carbon filter in your growth tent’s ventilation or exhaust system.

Ventilation

Proper ventilation and air circulation within the grow area helps to strengthen your plants’ stems, resulting in stronger, healthier plants. Having a combination of the proper exhaust system as well as circulation will also help to control room temperature and humidity within your grow room. Ventilation and circulation are also vital factors for keeping mold and pests to a minimum.

When proper airflow moves across your marijuana plants, it helps reduce the moisture that is naturally created during the transpiration (water evaporation) process. Decreasing this moisture can help prevent powdery mildew, mold, and bud rot (a type of mold infection). Some growers use an exhaust fan.

Humidity

The wrong humidity levels in your grow environment can detrimentally affect the quality and yield of what you produce. When left unchecked, humidity levels can cause all sorts of issues, including bud rot, mold, mildew, and much more. By ensuring that you have proper ventilation and air circulation as well as humidity controls in place, you can help to mitigate concerns related to humidity.

Cannabis plants desire different humidity levels throughout the different phases of their growth. As a seedling or clone, humidity can be much higher (in the 65 to 80% range). As the seedlings or clones enter into the vegetative stage, they need less humidity, and growers look to provide 55 to 70% relative humidity. Once your beautiful ladies start to produce buds and enter into the flowering stage, however, that humidity level should be maintained between 40 and 50%.

Phases of Growing Cannabis

Let’s go over each of the stages of marijuana growth at a high level. For these references, we will be assuming that you are utilizing cannabis seeds rather than clones. If utilizing clones, the germination and seedling stages will not be applicable.

Phase 1: Germination

During this stage, marijuana seeds are exposed to hydration and begin to grow. It takes roughly 7 to 14 days for seeds to germinate.

Phase 2: Seedling

Once your seeds have popped and have been transplanted into their grow medium, they have entered the seedling stage and will continue to grow for a minimum of 2 weeks. The seedling stage is complete once you have determined which plants are females and males and have also removed the male plants from the crop and cultivation area. Starting with feminized seeds will produce female plants.

Phase 3: Vegetative

The vegetative stage is essentially the growth stage of your plants. On average, most cannabis growers will keep their plants in this stage for a minimum of 1 month. When purchasing clones, this stage could be much shorter. During this stage of growth, your plants should be exposed to light for a minimum of 16 consecutive hours a day.

Phase 4: Flowering

Once the vegetative stage is complete, and your flowering plants are ready to begin producing buds, it is time to change their light cycles, so they only receive 12 hours of solid light each day followed by 12 hours of complete darkness. During this stage, your plants will grow to their mature state. This stage of cultivation typically lasts one to three months.

Phase 5: Harvesting

Once your plants have grown to their full potential and their trichomes are showing that they are at the right stage under a microscope, it is time to harvest. Read more about the different stages of trichome development here. This is the final stage of cultivation when you must say goodbye to growing your plants and cut them down. The plants are chopped down, dried, trimmed, and cured.

Harvest time requires the most patience to achieve proper curing. One of the easiest ways to see if you have reached the proper cure is to simply try to smoke some of the flower in a bowl or joint. If it will not light or stay lit and still has a very plant-like flavor (think vine ripe tomatoes), it likely hasn’t reached its peak. Other than testing, you must trust your sense of smell and feel to determine if the flower has cured to its fullest potential.

Final Takeaway

As you can see, there is a lot to consider when setting out to cultivate cannabis at home. The great thing, however, is that no matter what space you have, what level of knowledge you possess, or how little money you wish to spend, there is a way to cultivate healthy plants at home as long as you have the dedication to doing so. Today, there are hundreds of books available that can assist with every aspect of cannabis cultivation, as well as many groups and communities across social media dedicated to helping at-home growers cultivate the best cannabis possible!

So what are you waiting for? Get out there and start growing today, and be sure to let us know what questions you may still have regarding growing cannabis at home in the comments below!

Indoor cannabis cultivation basics

Indoor cannabis cultivation is often seen as something difficult that can only be performed by specialists. Well, nothing could be further from the truth, since growing our favourite cannabis strains indoors is easy if we follow few simple instructions and are a bit constant.

In this post we’ll tell you in an easy and simple way how to build an indoor grow room, focusing on three important aspects: ventilation, nutrition/medium and the lighting system. If we keep these three elements under control and choose correctly our strains, indoor cultivation can become something simple and almost mechanical, although if we neglect some of them, both yields and quality can be seriously diminished.

For this post we used a 1,2 x 1,2 metres grow tent, with 2 metres of height. In the market we can find lots of different grow tent models, so finding the one that best fits into our growing space should be easy. In this way, controlling the temperature and humidity of the environment will be easier, besides keeping our plants away from external light sources that could interrupt the night period of our plants, something vital for a good flowering.

Cannabis Grow Tent

Summary for indoor cannabis cultivation

The most important factors when building an indoor cannabis grow room are:

Lighting System

Our plants need light to properly grow and bloom. Most lighting systems are composed of a ballast, a reflector and a bulb. Normally, we use white/blue light for the growth period (with less Watts) and orange spectrum bulbs for flowering (increasing the potency of the system).

Ballasts are necesarry for the correct operation of the lamps, and can be electromagnetic or digital. LEDs, CFLs and fluorescent tubes often have a built-in ballast, while we must purchase a ballast for HPS or HM bulbs.

We can find tens of different reflectors in the market, from the most simple models to the modern air cooled reflectors. Their function is reflecting the light produced by the bulb downwards the plants, so the materials used to manufacture them and their design is very important for optimal light reflection.

Depending on the temperature and humidity level of the grow room (also on the total Watts used), lights are often placed 40-60 cm above the tops of the plants. To be sure, check the temperature and humidity on the top of the plants so you know if you should raise (more cold is needed) or lower (more heat is needed) the bulb. Later we will see which are the best temperature and humidity ranges to grow cannabis.

  • Growth: 18 hours of light / 6 hours of darkness per day, white/blue spectrum. Commonly used systems: LEDs, CFLs, Fluorescent tubes.
  • Flowering: 12 hours of light / 12 hours of darkness per day, white/blue spectrum (MH) during stretch (first 2-3 weeks into flowering), orange spectrum (HPS) until harvest.
  • Autoflowering plants: 20 hours of light / 4 hours of darkness per day. White/blue spectrum during growth, orange spectrum for flowering.
  • Light should be off during the heat of the day. Use air cooled reflectors if temperatures are too high.

K13 Haze seedlings under fluorescent tubes

Growth stage, MH lamp

Naranchup plants flowering under 600W HPS

Ventilation

Ventilation is another key aspect in cannabis cultivation, since it allows our plants to breathe, lowers the temperature of the grow room/tent and filters and removes odours from the plants.

Check this post on ventilation of cannabis grow rooms for further details.

  • Air extractor: Reduces heat and humidity, helps renewing the air. Can be connected to a carbon filter/tubular ozonizer to filter the air coming out from the growing space, removing unwanted smells.
  • Air intractor: It should always be of less capacity (m3/h) than the extractor fan. Introduces fresh air in the grow room.
  • Fan: Helps preventing the formation of heat/air pockets, reinforces the structure of plants.
  • Normally, the ventilation system operates while the lights are on, and at regular intervals during the night period (you can use a timer to set the desired intervals).

SuperJuani plants at the beginning of flowering

Nutrition

Last but not least, feeding correctly our plants is obviously vital to achieve top grade cannabis buds. Basically, we should choose between organic or hydroponic cultivation. Each technique has its specific nutrients and growing media, available in any Grow Shop.

  • Soil for cannabis plants with slightly acid pH.
  • Solid or liquid fertilizers.
  • Nutrient solution pH: 6-6,8
  • Nutrient solution temperature: 20ºC
  • Nutrient solution EC: 1-1,6

Here you have a post with the Philosopher Seeds team explaining how to prepare a soil mix for growing cannabis.

  • Hydroponic medium (coco coir, clay pebbles, mapito, lava rock, etc) with slightly acid pH.
  • Liquid fertilizers
  • Nutrient solution pH: 5.5-6,2
  • Nutrient solution temperature: 20ºC
  • Nutrient solution EC: 1,2-1,8

Needed materials for building an indoor cannabis grow room

These are the basic materials for setting up an indoor cannabis grow:

  • Grow tent
  • Lighting system (ballast, reflector, bulb)
  • Ventilation system (air extractor, air intractor, fan, carbon filter)
  • Thermo-hygrometer
  • Timers for the lighting system (hours of light/darkness) and the ventilation system
  • Organic or hydroponic fertilizers with the corresponding growing media
  • Plant pots
  • Cannabis seeds

Cannabis and grow lights

Normally, the first thing a grower must consider is the lighting system used in relation to the available growing space. Unless this space is really small (in this case we’d use LEDs or CFLs), most growers choose the lamps with best power consumption/lumens relation, either MH (metal halide) or HPS (high pressure sodium) lamps.

The power and spectrum of the bulbs are also determined by the cycle of the plant: growth or flowering. During growth, cannabis plants do not require lots of lumens, but they do need a minimum of 18 daily hours of light. For this stage, white/blue spectrum bulbs are often used, and different types of light can be found: LEDs, CFLs, fluorescent tubes and MH lamps.

Prune the lower parts of the plants to focus production on the top parts

During bloom, and if we want to get best results, we should use orange spectrum bulbs and far more lumens than during the growth stage. The most commonly used lamps for this phase are High Pressure Sodium (HPS), with a photoperiod of 12 daily hours of light and 12 hours of complete darkness.

As we can see, when we grow marijuana indoors we decide whether or not to switch our plants to the flowering cycle by controlling the photoperiod inside our growing space. Logically, autoflowering plants – like White Yoda or Cheesy Auto – do not follow this rule, and flower regardless the photoperiod; the most used combination is 20 hours of light and 4 hours of darkness per day.

To keep temperatures as stable as possible, and even if we have a good ventilation system, we should always turn our light off during the heat of the day. If necessary, we can use air cooled reflectors to lower the temperatures 4-6ºC inside the grow room.

For our grow tent we used – always looking for maximum yields – a 400W MH bulb for the growth stage (18/6) and a 600W HPS for flowering (12/12).

Ventilation and indoor cannabis cultivation

Ventilation allows us to remove excess heat and moisture in the environment. Thus, and since our plants need to breathe, we need a constant renewal of the air inside the growing space, especially if we can also use our extractor fan to filter and remove the intense smell from our plants.

Using an extractor fan and an intractor (always of less capacity then the extractor) is often enough to create a nice environment for our plants, with reasonable temperatures and humidity levels and proper air renewal. Using a fan inside the grow room helps preventing the formation of air pockets. If we connect a carbon filter to our extractor fan – or a tubular ozonizer – we’ll also remove all odours from the air coming out from the grow tent.

Normally, plants develop better at 20ºC with the lights off and 26-28ºC with the lights on. Humidity should be between 60-70% during growth and around 50% during bloom. Most growers use thermo-hygrometers with Max/Min to monitor these values and timers to program the ventilation system according to the needs. There are also many different climate control units that automatically turn on/off our ventilation system.

As we can imagine, we should purchase the ventilation system according to the available growing space and the lighting system used, since part of its task is removing the heat produced by the lamps besides completely renewing the air in few minutes.

For our example, with a 1,2 x 1,2 meters area and a 400W HM for growth and a 600W HPS for bloom, a 125mm RVK/PK type extractor will be enough, with a 100mm intractor and a 15cm oscillating fan.

Nutrients and substrates for cannabis plants

We have the adequate lighting system for our grow room and have purchased the ventilation system according to it. We now have to decide what type of cultivation we want to perform. Although we can find tens of systems and techniques, we’ll focused on the easiest method, organic cultivation. In our honest opinion, organics is better in regard with quality of the final product.

We basically have two options here: using a light soil, with enough nutrients for 2-3 weeks, or using “All mix” type soils, with enough nutrients for a couple of months. If we choose the first option, we’ll surely have to add liquid or solid fertilizers to our substrate during the flowering stage.

Remember to water your plants when the substrate is still slightly wet and not completely dry, and use the correct fertilizers according to the cycle of the plant, growth or bloom. We recommend you to read this post on how to water cannabis plants in soil.

Properly fertilised plants grow strong and healthy

If we have to use extra nutrients, we can find solid fertilizers, which are mixed with the growing media and work great for guerrilla grows and autoflowering plants, or liquid fertilizers, used in each watering at moderate doses especially with relatively long flowering strains like Jack el Frutero or SuperJuani. The nutrient solution temperature must be around 20ºC, with a pH near 6,5. If we use liquid nutrients and we have a EC meter, we should use 1-1,2 Ec during growth and 1,4-1,6 during bloom.

Cannabis cultivation

Once all this is clear and we have built our grow room, we can fill the pots with our soil mix, water it a bit and sow our seeds. Under a 18/6 photoperiod, our plants will grow during 2-4 weeks, depending on varieties: 2-3 weeks for Sativas, 3-4 weeks for Indicas like Black Bomb or Tropimango.

We can harvest top grade buds at home

When they’ve reached the adequate height, we can switch to flowering (12/12 photoperiod). If we have enough space, transplanting into larger pots is recommended. Once the plants start developing flowers, change to flowering nutrients.

A couple of weeks before the harvest, stop adding nutrients and water your plants with plain water (flushing stage).

Indoor cannabis crop inside a grow tent

We hope these tips helped you to start your indoor cannabis grow. You’ll see the effort is worth it, there’s nothing like homegrown cannabis!