BudTrainer's Home Growing Academy

Lesson #1

Cannabis Growing Basics & How to Select Seeds for Maximum Yield

Updated on Sep 10, 2022

Cannabis flowers inside a grow tent

"Want to know the fastest and easiest way to grow top-shelf bud?"


“Simple: learn the basics, and grow healthy plants."


Growing high-quality cannabis is nothing more than growing healthy plants. Plants that thrive and love their environment while producing top-shelf bud. And guess what? In order to grow healthy plants all you have to do is learn the basics about cannabis cultivation, and make sure that you don't screw up. In fact, 90% of growing cannabis is simply not screwing up.

If you are growing for the first time, this lesson will teach you the basics of growing cannabis and selecting seeds, and you will be ready for Lesson #2: How to Plant (& Transplant) Cannabis Seeds for Maximum Success.

No more waiting. Let’s get right into it!


The first thing you will have to decide in your growing journey is WHERE you are going to grow: indoors or outdoors?

1. Growing Indoors vs Outdoors

  • Do you have an outdoor space that gets lots of sun?
  • Do you have space in the basement to set up an indoor tent?
  • Do you have money to spend, or no money to spend?
  • Do you care more about quality or quantity?

These questions are important because they will help you decide whether you are going to be growing indoors or outdoors. Let’s look at the differences between both.

1.1 Budget 

Growing marijuana outdoors is a lot cheaper than growing indoors for one main reason: the sun is free and provides a lot of energy to your plants, yielding large amounts of weed at the end of the year. You can easily grow plants that yield ½lb to over 1lb of weed with as little as $100 per plant (pots, soil, nutrients, etc). 


If  you can grow 1 plant in your backyard with $100 and have a yield of up 1lb, this is the same as paying $0.22 per gram. Not to mention that for most people, 1lb of weed is more than enough for the whole year!

Outdoor cannabis plants trained on a trellis net and planted on the ground

Cannabis plants growing outdoors


Growing marijuana indoors, on the other hand, costs more before AND after you start growing. A decent indoor setup that grows 1lb of cannabis every 4 months costs around $1,000, the electricity bill will come to around $200 per year, and everything else (nutrients, water, etc) adds another $200.


This means that, in the first year alone you are spending $1,400 for 3lb of weed. If we were to add nutrients and water to the bill, this means you are paying an average of $1.03 per gram in the first year, and as little as $0.30 per gram every year thereafter (compared to $0.22 from outdoors).

Indoor cannabis plants in a grow tent with a BudTrainer banner in the background

Cannabis plants growing indoors


1.2 Quality 

Growing cannabis outdoors is always dependent on the conditions of the environment around your plants. If it rains too much, your bud won’t be as good. If there are too many bugs or mold, your bud won’t be as good. If it is too dry, your bud won’t be as good. And so on. Basically, the quality (and thus the THC content) of your outdoor plants is directly proportional to the quality of your environment.


Since the environment outside is never consistent, this means that growing outdoors will always see a few bad days here and there, which inherently will compromise the quality and THC content of your bud. 


In fact, most licensed commercial outdoor cannabis growers end up selling their cannabis for extraction since they don't pass the microbial tests required at the lab, and nor do they get the high-THC levels that indoors cannabis does.

Two cannabis plants in the BudPots being trained with the BudHuggers and with a trellis net on a wooden frame

Outdoors cannabis plants are at the mercy of the weather


Growing cannabis indoors, on the other hand, removes all of the problems that the outdoors environment creates. When growing marijuana indoors you can set a consistent temperature and humidity, you can adjust the height of your lights, and your plants are never at the mercy of the weather. 


A controlled environment is always better for cannabis, which is why growing indoors yields the best and cleanest results, and as such more potent and higher quality bud.


TIP: never open your grow tent right after being outside during the Summer since you can have pests in your clothes. 

4 indoor cannabis plants inside the BudPots in a white an wooden growbox, all in the early flowering stage

Cannabis plants growing in an automated grow box


1.3 Schedule

Growing weed outdoors requires you to stick to the schedule of the sun. In Northern US States and Canada, the earliest you can safely plant marijuana plants outdoors is May, and the latest you should harvest is at the end of October. As a rule of thumb, if it is below 50F/10C outside then it is too cold for your plants. 

TIP: In order to get a head start, you can plant your seeds indoors around January or February, grow them until May with a small LED light, and then transplant outdoors. This will give your plants a head start and they will already be quite big by the time you are transplanting them outdoors. 
Diagram of the outdoor growing schedule for cannabis in North America

Growing schedule for outdoor cannabis in North America


Growing weed indoors, however, puts the schedule fully under your control and you never depend on the season to grow. You can start and finish your plants whenever you want, and you can also grow during the Winter months. This allows you to get 3 or 4 harvests per year in a single grow tent, under your own terms.
Diagram of how many cycles you can grow with an indoor setup every year.

Growing schedule for indoors plants with a 4-month growth cycle


Putting it all together




Growing indoors and outdoors clearly have their advantages and disadvantages. What we encourage every grower is to do to both: if you have the space and a lot of light exposure, don't let that sun go to waste. It's super fun to grow plants outdoors and to see how massive they get, and it's a very unique process in it's own. If you have the space indoors to set up a grow tent, this means you can not only start your outdoor plants early but also control every aspect of your environment. You can also continue growing indoors while growing outdoors during the Summer, and this allows you grow strains specific to each environment, getting the best of both worlds. 


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2. Growing Indicas vs Sativas

Before we talk about indicas and sativas, it is important to note that there are almost no 100% pure sativas or indicas in the world today. In order to find pure indicas or sativas you need to go looking for landraces that still live in the wild but are not nearly as potent as today’s hybrids.
Also, the percent (%) indica and sativa labels that each strain comes with has no scientific basis whatsoever - it’s simply someone looking at the plant and going: that looks like a 50%/50% indica/sativa - and the label lives on. 

For these reasons, we believe that the labels indica and sativa should never be used to describe the type of high that a marijuana plant creates.

However, when it comes to growing, there are some key differences between the two types.

Wild cannabis plants with the sky in the background

Wild sativa cannabis landraces


2.1 Leaf Shape

Indicas have much wider leaves, which means they need to be defoliated and pruned more often since their leaves block a lot of airflow and light absorption from below the canopy.


Sativas have thin-fingered leaves with much more space between each leaflet, which means they don't need to be defoliated nearly as much as indicas do.


2.2 Plant Size

Indicas grow to be much shorter plants, which is why they are so popular for growing indoors and are the most common form of illicit cannabis available. 


Sativas, however, are much taller and lankier, and they need a lot more training in order to keep their branches tame. This is why they are a great choice for growing outdoors.

Indicas vs sativas diagram showing the differences in size and leaf shape

Leaf shape and plant size between indicas and sativas


2.3 Internodal Spacing

Since they are shorter, indicas have much shorter internodal spaces. This means they grow pairs of leaves and branches very close to each other.


Sativas, since they are much taller, have long spaces between their branches and leaves. 


As a consequence, indicas need to be pruned more often while sativas need to be low-stress trained more often.

Cannabis seedling with arrows pointing to the nodes and internodal spaces

Internodal spacing on a cannabis seedling


2.4 Flower Size

Indicas have fewer but much denser buds, sometimes as thick as a fist. This means you need a lot of airflow while flowering and while drying, or mold can form in your bud.


Sativas have a lot of smaller buds spread throughout the branches. While this is not a concern for mold, sativas do take a lot longer to trim since their buds are smaller. 

Defoliating the stronger growth site of a cannabis plant's node

Internodal spacing on a cannabis seedling


2.5 Flowering time

Indicas finish their flowering stage after 7 to 9 weeks whereas sativas take 9 to 12 weeks to finish. This means you can grow more indica plants in one year than sativas, since they will almost always be a few weeks ahead in the flowering cycle.
Defoliating the stronger growth site of a cannabis plant's node

Indicas have faster flowering cycles than sativas


3. Vegetative & Flowering Stages

Did you know that marijuana has two stages of growth - one for growing only branches and leaves and another for only growing flowers (i.e. bud)? That’s right! Unlike tomatoes, which grow branches, leaves, and fruit at the same time, cannabis plants can only do one thing at once: either grow branches and leaves (called the vegetative stage), or grow flowers AKA bud (called the flowering stage).
cannabis plants in the veg stage in an indoor grow tent with a trellis net over top

Indoor cannabis plants in the vegetative stage

cannabis plants inside a grow tent in the flowering stage and ready for harvest

Indoor cannabis plants in the flowering stage

What causes weed plants to switch from the vegetative stage to the flowering stage is the availability of light AKA photoperiodism. When cannabis plants get 16h or more of light per day, they stay in the veg stage. However, when they get 12h of light or less, they automatically switch to the flowering stage and start producing buds. Let’s understand why.

3.1 Growing Photoperiods Outdoors

When days are long and the nights are short, weed plants think that it’s Spring and Summer time, so they only grow branches and leaves in order to gain as much size as possible. 


However, as Fall approaches and the days get shorter, cannabis plants realize Winter is coming to kill them, so they switch to the flowering stage (around August), when they only grow flowers in order to reproduce and make seeds before they die of cold. It’s a smart strategy for them: grow when there is light, reproduce when there isn’t. 


Outdoor cannabis plants are usually ready for harvest in October every year - right before the frost.

outdoor cannabis plants in the flowering stage almost ready for harvest, with a swing in the background

Outdoor cannabis plants in the late flowering stage


3.2 Growing Photoperiods Indoors

What photoperiodism means for growing cannabis indoors is that if you leave your lights on for 18h and off for 6h, your plants will think it’s Spring and stay in the veg stage. You can stay in the vegetative stage for as long or as short as you would like, as long as the lights are in the 18h/6h schedule. In the BudTrainer method we recommend staying in the veg stage for 6 to 8 weeks, but if you want to grow massive plants or do a canna bonsai, you can leave your lights on for 18h/day for multiple months.

Cannabis seedlings in an indoor grow tent with a BudTrainer banner that says I Grow Big Buds in the background

Indoor cannabis seedlings in red solo cups

In order to flip your indoor marijuana plants to flower, simply switch your light schedule from 18h/6h to 12h on and 12h off every day. Your plants will be tricked into thinking it’s Fall time, and will start producing flowers instead of branches and leaves only. The flowering period, different from the veg stage, doesn’t last indefinitely - in 8 to 12 weeks your plants will be ready for harvest (depending on which strain you are growing). However, there is one exception to photoperiodism: autoflowers.

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4. Autoflowering Cannabis Plants

Similar to photoperiodic cannabis plants, autoflowers can only either grow leaves and branches, or they can produce flowers - but never both. However, autoflowers don’t care about the light cycle in order to flip to flower - they flip even if under 24h of light per day (i.e. 0 hours of night). While autoflowers don't reach levels of THC as high as photoperiodic strains, they are getting up there quickly and it is just a matter of time until autoflowers are as potent as their cousins. 

Most autoflowers have a veg cycle of 20 to 30 days until they automatically switch to the bloom cycle, which lasts 55 to 70 days. This means you can go from seed to harvest with autoflowers in as fast as 75 to 100 days (depending on the strain). While autoflowers still don’t have the same high-THC profiles as photoperiodic plants, they are very close and are a great choice for many growers.

Two cannabis autoflowers in the late flowering stage, beside each other with a white background with BudTrainer's logo

Autoflowers ready for harvest 80 days after planting.


4.1 Growing Autoflowers Outdoors

If you are growing autoflowers outdoors, they won’t care about what time of the year it is in order to flower since they are not sensitive to light. 


In fact, if you select a 75 to 90-day strain, you can plant one batch of autoflowers in early May, harvest them in late July, and plant another batch in July for a late October harvest. 


Many outdoors commercial growers do this so that they can get two crops in one year, and so can you!

Commercial cannabis plantation of autoflowers with thousands of plants

Commercially grown outdoor autoflowering marijuana plants


4.2 Growing Autoflowers Indoors

If you are growing autoflowers indoors, you can keep your lights on for 18h to 24h a day the entire time and your autoflowers will be ready to harvest in 75 to 100 days without your ever having to switch to 12h/12h.


TIP: For maximum yield, leave your lights on for 20h and off for 4h from seed to harvest. We do not recommend leaving your lights on for 24h a day because this impairs root development (roots like to grow at night).


Cannabis flower in the late stages of growth inside a growbox

Outdoor cannabis plants in the late flowering stage


"How can autoflowers tell when it is time to flower?"


“HINT: It's not based light availability"  


How Autoflowers Start Flowering

While some regions of the world have very short days in the Winter and long days in the Summer (e.g. Greenland), other regions have almost the same day-length all year long (e.g.. Thailand).

Since the switch from Summer to Fall is too fast in regions far North and South (i.e. it goes from hot to cold very quickly), cannabis plants that grow in those regions don’t have time to wait for the days to become short in order to start flowering - they must do it while the days are still long, or they will end up frozen in Winter before they could mature their seeds. 
Diagram showing the summer solstice and explaining how it works
Diagram showing the winter solstice and explaining how it works
Conversely, strains that are too close to the equator can’t rely on day length to flower because every day has 12h of light and 12h of dark, all year long. Because of this, autoflowering cannabis plants had to rely on a system called the C:N ratio in order to flower. Let’s see how it works.

The C:N Ratio

The Carbon to Nitrogen Ratio (C:N Ratio) is a phenomenon that triggers the flowering cycle on plants, just like changing light cycles does. More precisely, this happens after the amount of assimilated carbon (C) in the plant compared to nitrogen (N) surpasses a certain threshold. 


When this ratio is high enough, it means your plant has stored enough sugars (Carbon = Carbohydrates) in relation to leaves (Nitrogen) to start the flower cycle and sustain those flowers until it dies. 


It’s as if your plants said: my tanks are full of sugars and I can get all the way to the end of the flower stage with this much energy. And so they flower.

Autoflowering cannabis plant that just started flowering

Cannabis plant that just started flowering


5. Cannabis Sex: Male vs Female Plants

Most plants in the world are monoecious, which means they have both male and female organs on the same plant, which allows them to pollinate themselves. Cannabis, however, is a dioecious plant, meaning it has plants that only produce flowers with male organs and plants that only produce flowers with female organs. 

When the pollen from the male flower lands on the pistils (the white hairs that stick out) of the female flower, a seed is born. While male plants don’t have any cannabinoids and can’t get you high, they will pollinate your female flowers and yield lots of seeds. This is why, whenever you identify a male plant in your garden, you should remove it as fast as possible (unless your intention is to breed). 

Diagram explaining the differences between dioecious and monoecious plants

The Difference Between Cannabis Males & Females

The difference between male and female cannabis plants is pretty easy to identify: male flowers don’t have any white pistils, and they show their round pollen sacks (which most people refer to as “balls”) before the female plants show their pistils, making them easier to pick out of the garden.


You can only identify males and females after you have switched your plants to the flower cycle. It takes 4 to 7 days for males to show their pollen sacks and 6 to 10 days for females to show their white pistils. 


PRO TIP: after week 3 of the veg cycle, you can flip your light schedule to flower for one week in order to pick out the males, and then switch it back to the 18/6 schedule once you know you only have females. While this delays the growth cycle a little bit, it's much better than growing a male for 6 to 8 weeks. 

Diagram showing the difference between cannabis male flowers and female flowers

Anatomy of male and female cannabis flowers

Male cannabis flower full of pollen sacks

Male cannabis flower with pollen sacks

female cannabis flowers full of white pistils

Female cannabis flower with white pistils

While growing male plants really sucks, there is a proactive solution to never growing them again: feminized seeds.

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6. Feminized vs Non-Feminized Seeds

Most cannabis seeds are non-feminized, meaning you have no idea whether what you are planting is a male or a female plant. You always have to wait until your plants flower in order to tell which is which.

Feminized seeds, on the other hand, are seeds that always yield female plants. Instead of risking your plant being born a male, feminized seeds remove that risk altogether. While they are more expensive than regular seeds, feminized seeds are worth every penny because there is nothing worse than growing a male plant for weeks, finding out it is a male after it has flowered, and then having to throw it out in the garbage.


Cannabis seeds on top of a white surface

Feminized seeds look the same as regular seeds


"So how do they tell if a seed is a male or a female?"


“They actually don’t. Feminized seeds are born that way"  


How Feminized Weed Seeds Are Made

In order to tell if a seed is a male or a female, you would need to run a DNA test, and in order to do that you would have to crush your seed. This is why feminized seeds have to be created that way. But before we get there, we need to understand what hermaphrodites are.

Cannabis hermaphrodites


Hermaphroditic weed plants are plants that have both male and female flowers. Hermaphroditism happens genetically to a very small percentage of cannabis plants that were just born that way, but it happens most often when cannabis plants get really stressed, such as being too close to the lights, high temperatures, lack of fertilizers, or dry media. 


When stresses like these happen, the female flowers think they are under existential threats and as a result they put out a few male flowers (also known as bananas or nanners) in an attempt to auto-pollinate, and at least generate a few seeds before it dies.


Cannabis female flower with male bananas or pollen sacks

Male pollen sacks on a dried female flower


Female DNA


The thing is, the male flowers that are created in a female plant due to stress have 100% female DNA since they were born out of a female plant. When these male flowers pollinate the female flowers from the same plant, they end up producing seeds that also contain 100% female DNA (50% from the male and 50% from the female) - which is why seeds born this way always end up growing female plants - AKA feminized seeds.

Cannabis flower full of seeds

Cannabis flower full of seeds

In order to commercially make feminized seeds, breeders choose their best female plants and then spray them with silver nitrate or silver thiosulfate, which are both inducers of male flowers in female plants. This plant under the purple light was sprayed 3 weeks before the picture was taken, and now it has both pollen sacks and pistils in the same female plant. This plant is ready to auto pollinate and generate feminized seeds.
Cannabis hermaphrodite flower induced by silver thiosulfate

Cannabis hermaphrodite induced with silver thiosulfate


7. How to Select Top-Shelf Genetics

Now that you know all of the basics about cannabis plants and growing, it's time to select your genetics. This is an important step, because if you don't select your seeds adequately, they won't grow to their fullest potential in your own unique setup. For this reason, we recommend selecting a reputable seed bank that has great reviews, and that can safely and discreetly ship seeds to your location.

Selecting Your Seed Bank

Most seed banks will have a lengthy description of the strain they are selling as well as the recipe for growing it. No one knows how to grow their strains better than the seed banks do, so following their recommendations is generally good practice, at least as a starting point. If the seed bank you are buying from doesn’t give you information on the growth cycle of your plant, we would recommend finding another seed bank that does (this is the least they should be giving you).

Your seed bank should be able to tell you the percent THC and CBD that their strains yield. If you want high THC, high CBD, or a blend, make sure you read the labels of your strains before selecting them. Always assume you will be getting the lower end of the % range since usually only the seedbanks themselves can grow it to the top range (e.g. 18% to 25% THC means you will likely get 18% to 20%).

Choosing Your Strains

You can never tell what the plant you are going to grow will be like, but the closest you can get to it is by looking a the pictures of the flowers your seed bank has provided. The same strain will grow very differently from seed bank to seed bank, so make sure to inspect what your own seed bank's strains look like. For example, blue dream can be a very different strain from place to place since it has been so popularized recently. This means that not every blue dream will be the same!

Lastly, make sure to read the profile of the strain you are about to purchase and check whether you can create the same growing conditions that the strain needs. E.g. If the plants grow tall, do you have space? Is the flowering cycle the same length for all strains that you are growing together? If the plants grow short, do you have enough airflow?

Outdoor-Specific Strains


If you are growing outdoors, make sure to look for (AKA Google) strains that were bred to grow outdoors. These strains will have much better pest and weather resistance than indoor strains, and will yield much better results. In fact, some indoor strains will rarely make it outdoors since they are so delicate and sensitive to outdoor conditions. Most seed banks will have outdoors versus indoors seeds for you to select, so make sure to buy accordingly.

Now It's Time To Get Growing!

Now that you know the basics of cannabis growing, it’s time to get your seeds picked and planted!

If you are ready to learn the best way to plant (and transplant) cannabis seeds, check out


Want to continue learning? Here are a few more lessons for you!

Lesson #1: Cannabis Growing Basics And How to Select Seeds for Maximum Yield
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Lesson #2: How To Plant (and Transplant) Cannabis Seeds for Maximum Success
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How to Top Cannabis Plants: The Method & The Science Behind This Old Trick
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Learn to Grow Like The Pros

And be the first to know about new cannabis-growing articles, product releases, and promotions.