Table of contents

In this first article, you’ll find information about the Cannabis plant’s cycle, reproduction, and growing requirements. It’s an overview of the Marijuana growth, from seed to harvest. We’ll be updating and publishing new content soon!

Growing Cannabis at home it’s not difficult at all and it’s very rewarding, but requires some knowledge and effort.

Cannabis plants

So, where to start when growing Cannabis? Let’s talk about the plant.

Cannabis plants may be male, female or hermaphrodites. This means that each plant has male or female reproductive organs. Female cannabis plants produce female flowers or “buds” and, in order to produce seeds, they need to be pollinated by a male cannabis plant. 

When female plants are deprived of the male plant pollen, they produce bigger and fatter buds with no seeds in them. These are usually called “sinsemilla” (“no seed” in Spanish) and it’s the most commonly found product in dispensaries, stores and home growing yields alike. 

cured Cannabis bud
Cured Cannabis bud. PH: David Cardinez

The reproduction of the Cannabis plant may be sexual or asexual. 

  • Sexual: seeds
  • Asexual: clones 

Female Cannabis plants

Female cannabis plants produce inflorescences (clusters of small flowers) or “buds”. These buds contain the biggest cannabinoids concentration in the plant. That’s why lots of growers put all their efforts into harvesting the biggest and frostiest buds.

Cannabis plant late flowering stage
Cannabis plant – late flowering stage.
PH: Robert Baker

Cannabis plants usually start to show sex with pre-flowers, around week 4-6 from seed. Female pre-flowers look like a pair of white hairs. In fact, pistils or “hairs” are the female reproductive structures of the plant and that’s where they produce the seeds.

Male cannabis plants

Male cannabis plants produce male flowers, but they are not capable of producing buds. Male flowers look like little “balls” or “bananas” and contain pollen grains, but no trichomes. Pollen grains contain male gametes (sperm cells). Long story short, when pollen finds compatible pistils, the sperm is transferred to the ovule, and the female plant starts producing seeds. 

Hermaphrodite Cannabis plants

Cannabis plants are basically dioecious (they have male and female sex organs in separate individuals), but sometimes monoecious Cannabis plants may occur, and they are commonly called “hermaphrodites” or “hermies”. These plants have both male and female organs in the same individual. Actually, there exist two types of monoecious Cannabis plants: 

“True hermaphrodites” have both male and female organs but in different parts of the plant. 

“Mixed-gender plants” have sexual organs resembling “bananas” or “nanners” growing from female plants. These “bananas” are actually pollen sacs and may pollinate themselves and even our female plants. 

Hermaphroditism is not desired in Cannabis crops. The majority of growers take out the hermaphrodite plants immediately after identifying them. 

Some factors that lead to hermaphroditism are:

  • plant stress
  • high temperatures
  • nutrient deficiencies
  • root rot
  • light leakage in dark periods
  • bad genetics.

Cannabis seeds

Plant sexFlowering period
regularphotoperiodic
feminizedautomatic

Regular Cannabis Seeds

Growing regular Cannabis seeds is one of the most popular and easiest ways of growing marijuana plants. It’s easier to find and produce regular Cannabis seeds, and they are obviously cheaper than feminized seeds. These seeds may produce male or female plants. 

Feminized Cannabis Seeds

Many growers buy feminized Cannabis seeds and start their crops knowing they will be raising only female plants. They do this to avoid wasting resources and having to wait until regular seed shows its sex. Feminized Cannabis seeds will produce only female plants. They can be costly but you know your resources (fertilizers, light, soil, space…) are being used at their full capacity in plants that will develop female cannabis flowers.

Cannabis is an annual plant, its flowering period is determined by the seasons and when the cycle ends, the plant dies. Photoperiodism is a developmental response to the changes of duration in the cycles of light and dark periods.

Outdoors, Cannabis plants sprout in Spring and grow in the vegetative stage during Spring and Summer, when they start blooming. When Autumn is coming and the days start to grow shorter, Cannabis plants stop growing in size and develop fat, resinous buds instead, in an attempt to be pollinated.

cannabis seeds
Cannabis seeds – Ph: Ulrike Leone

Photoperiodic Cannabis seeds

Cannabis, according to its photoperiodic response, is considered a short-day plant. This means it starts to flower and produce buds instead of growing in size in Autumn when the days grow shorter. To replicate this process indoors, growers shorten the light period usually from 18 hours light and 6 hours of darkness (18/6) to 12 hours of light and 12 hours of darkness (12/12).

If the plant continues living under an 18 / 6 hours of light regime, it will stay in the vegetative stage and will not start flowering. This is a good idea if you are growing mother plants for cloning.

Autoflowering Cannabis seeds

Autoflowering Cannabis seeds produce female plants that don’t need photoperiodic conditions in order to change from the vegetative stage to the flowering stage. They are designed to start flowering at a fixed period of time, despite the environmental conditions and light stimuli. This makes Autoflowering Cannabis a good choice for beginner growers because they don’t have to worry about guessing if the plant is male or female or when to change the photoperiod. They have fixed and shorter life cycles so they will develop faster than photoperiodic strains.

Cannabis cloning

Growing cannabis without seeds is not only possible but actually an effective way of growing Cannabis plants.

Growers usually clone the plant that has their favorite traits and/or the one that seems healthier. This plant should be in the third or fourth week of vegetative growth. Growers usually take the cuttings before the pre-flowers appear. Clones have the same age as their mother, so these cuttings can be put to flower once they had established, even if they are tiny; or you can let them grow as much as you want before putting them to flower. Growers look out to these traits to make their decision: Taste/Aroma, vigor, yield, potency and appearance.


Cannabis Growing requirements

Growing medium

The main functions and requirements of a growth medium are: providing physical support to the plant, allowing root respiration, and holding available water and nutrients for the plant. As long as the roots have reasonable space, the right amount of water, good aeration, and available nutrients, your plant will grow steady and healthy. If one of these factors is missing, the plant is bound to experience growing issues. 

A Grow medium, also known as the substrate, is the material or mix where your plant’s roots grow and thrive, for example, soil, coco coir, water, etc.

Growing Cannabis in soil

Soil mix is an excellent medium to start growing, provided that it has the right balance between solids (organic and inorganic matter) and empty spaces, where air and water will flow. Aeration is a key factor in order to keep roots healthy. To avoid soil compaction, you need to add materials such as perlite, vermiculite or coco coir so roots can develop in pore spaces between the solid particles. 

Preparing soil Cannabis crop
Preparing soil. PH: Neslihan Gunaydin

There are many commercial soil mixes with added nutrients so you don’t have to worry about applying any additional in the beginning. You can also prepare your own soil mix and add the nutrients needed for each stage.  

Growing Cannabis in Hydroponics

Growing cannabis without soil is possible, and it’s one of the most productive methods to achieve big yields in a few months.

Is it hard to grow Cannabis in hydroponics? Not at all, but it requires an initial investment in time and set up, and some extra care.

Cannabis seedlings in hydroponic system
Cannabis seedlings in a hydroponic system.
PH: Alicia M

“Hydroponics” includes many popular and effective methods of growing cannabis, in which plant roots are exposed to a nutrient-infused and air-pumped water solution. You can choose between different setups, such as deep water culture, ebb, and flow or drip system for naming some of them. There are as well many kinds of substrates to help the roots anchor themselves, such as perlite, clay pebbles, and Rockwool. 

These methods are known for delivering a faster and more abundant yield, but they require a higher investment of time and money. In the process, you’ll need to monitor and keep track of the plant nutrients’ intake, control temperature, pH and ppm changes among other factors. 

Growing Cannabis in Coco coir

Coco coir is made of coconut husk fiber and it’s known to be an excellent growing medium. It may be used alone or mixed with soil and perlite for better aeration. It’s great to avoid soil compaction and to retain water and nutrients without drowning the roots. As coco coir is an inert medium, it’s vital to add the correct amount of nutrients for each stage to feed the plants if it used alone.

Water

Water quality varies A LOT depending on your location. 

It may go from hard water (high content of dissolved minerals) or soft water (very little mineral content or none). Testing water pH is crucial, regardless of the source.

Cannabis loves a pH reading between 6-7. 

Tap water

Tap or well water is generally ok regarding it has correct pH levels (it may need a little adjustment) and a low ppm. It normally contains minerals like calcium, magnesium, iron, and copper which the plant can make use of. On the contrary, filtered water, for example by RO (Reverse Osmosis), may not have any minerals left. Hard water is not recommended for watering any plants and not recommended for clones. 

Reverse osmosis water

Growing cannabis with RO water is another popular option in places where fresh clean water is a scarce resource. Reverse osmosis is a filtration method than can remove up to 95-99% of dissolved salts in any water sample. You can use water filtered by reverse osmosis, but PH can be harder to adjust. You’ll have to add all the micro and macronutrient needed to the watering solution. 

Adding fertilizers makes the water saltier which decreases the osmotic potential. Rather than helping the plant, this reduces the uptake of water once roots start developing. Adding fertilizers works against the whole process of rooting. However, you can add root stimulating products such as rapid start, seaweed extract, b vitamins, and phosphorus. 

Nutrients

The main fertilizers that the Cannabis plant needs to develop are Nitrogen (N), Phosphorus (P) and Potassium (K). 

N is key during the vegetative growth, with lower levels of P and K. When the plant starts to bloom, the concentrations of P and K must be increased progressively, while the N concentrations are lowered. That is why there are specific fertilizers for vegetative growth and flowering. 

Other secondary nutrients will be necessary for the correct development of the plant. These are Magnesium (Mg), Calcium (Ca) and Sulfur (S). 

Finally, the micronutrients are necessary but in a minimum concentration. These are Zinc (Zn), Manganese (Mn), Iron, (Fe), Boron (B), Chlorine (Cl), Cobalt (Co), Copper (Cu), Molybdenum (Mb) and Silicon (Si). 

Several brands of fertilizers offer fertilizer kits specially formulated for each stage with the necessary nutrients. It is recommended to start with the dose indicated by the manufacturer or even a little lower to avoid saturation and gradually increase the amounts until the desired results are achieved. Be careful that if you go over the required amounts, the plant can suffer stress, damage and even die from excess fertilization. 

These fertilizer kits already bring in their formulas all the essential chemical elements and are in a form available to the plant. Special care must be taken with the quality of irrigation water and the initial substrate. The plant needs a growth medium that provides support, nutrients and root aeration to be able to absorb the water and the chosen fertilizer solution.

Light

Outdoor cannabis crops thrive under the sunlight, but what about indoor cannabis crops? 

First of all, incandescent light bulbs are not recommended for growing Cannabis at any stage. 

Cannabis plant flowering indoors
Cannabis plant flowering indoors.
PH: Micripper

These are the most used kinds of lamps for growing Cannabis 

Fluorescent lights (CFL)

These are one of the cheapest and more effective lamps for growing Cannabis. They consume less electricity than other options and produce less heat, have an adequate light spectrum. These lamps are suitable for young plants because they won’t burn them. They produce less yield than LED lights but they are much cheaper.

High-Intensity Discharge grow lights (HID)

The most popular HID for Cannabis home growing are Metal Halide (MH) for the vegetative stage. and High-Pressure Sodium (HPS) for the flowering stage. They usually come with a reflector and a ballast. They are more expensive than CFL lights and produce a lot of heat, so ventilation is crucial to achieving good yields in reduced spaces using these lights. 

LED lights

Growing Cannabis with led lights has become a very popular technique in the past few years. LED light panels nowadays come with a full spectrum of light needed by the plant for the whole cycle and produce more abundant yields than other options. They don’t produce much heat or noise and are very durable, but can be costly at the beginning. Led grow lights come in different presentations, and it’s up to each grower to find their perfect setup. 

Air

Aeration is fundamental for any plant to grow healthy and Cannabis plants are not an exception. Growing outdoors doesn’t present any problems. In an indoor environment is key to have a good exhaust fan, a constant intake of fresh air and an extra fan for moving air inside the environment. Plants will grow healthier and stronger.


Cannabis plant life cycle

When we are about to start growing Cannabis, we all ask the same question: how long does it take from seed to harvest? We want to see results (buds) as soon as possible. If you are growing indoors, the process is much shorter and you can even control it as you please. If you are growing outdoors, the plant will live for several months along its natural life cycle. 

Short answer: Cannabis may take from 3 to 5 months to grow indoor and up to 8 months outdoor.

Cannabis seed germination (3 to 10 days)

This is how the life of the Cannabis plant begins. A viable seed looks brown with some stripes, hard to the touch and dry. If it feels weak or it’s white or light green, it’s probably an undeveloped seed and it won’t produce a healthy plant.  

For germinating, Cannabis seeds need some humidity, air, and water. It’s better to keep them in a dark humid place, for example between two plates in a damped napkin. When the seed opens up and starts showing the first white tap root, it’s time to put it in its next growing medium. This root starts to develop and eventually the plant produces the two first oval leaves, called cotyledons. Now it’s a seedling!

Seedling stage (2 to 3 weeks)

The little Cannabis plant starts producing serrated leaves, but not the digitate leaves we all know, only single serrated leaflets. As the plant grows, new leaves with more leaflets start to develop until the plant produces the characteristic digitate leaves with serrated borders we can all identify as Cannabis fan leaves. When these leaves appear, the plant enters into the vegetative stage.

Vegetative stage (3 to 16 weeks)

The time for vegetative stage indoors is up to your preference. Most growers vegetate their indoor plants for 4-8 weeks, depending on the desired plant size. Cannabis plants are able to start flowering from the 3rd week of the vegetative stage, but those plants will be smaller. Giving your plants more vegetative time will result in bigger plants and more likely to produce higher yields. Most growers choose to let plants vegetate for longer because giving them more time to grow results in bigger plants.

Flowering stage (8 to 11 weeks)

Bloom and flowering phases are essentially the same thing, but in those 7-9 weeks, plants go through many changes. It’s usually divided into weeks or three stages. 

Flowering initiation phase

From week 1-3 plants stretch and grow in size and height, start blooming (producing pre-flowers or “hair”). This is the best time to train your plants if you want to do so.

Mid-Flowering phase

From week 4-5 plants stop growing in size and star growing, fattening their buds and darkening their pistils.

Late flowering / Ripening phase

In the last three weeks, buds gain the most weight. Start checking trichomes for signals or ripening to know when to harvest. Remember to flush your plants before harvest.

We recommend reading each strain description and following their growing instructions. Start monitoring trichomes and pistils changes around week 7 with a magnifying glass or loupe. 

How long does the flowering stage take?

The duration of the flowering stage varies among different strains.

The flowering period for indica strains is typically around 8 weeks, but it may take up to 10 weeks. Sativa strains may take up to 10-12 weeks. Typically, hybrid strains will take up to 6-10 weeks to fully develop.

Around week 8 of the flowering stage, buds will start fattening quickly. You’ll see that trichomes and pistils are maturing and changing colors. It’s up to each grower the harvesting moment, depending on the effects and flavors desired. Usually, when trichomes turn from transparent to a milky / white-ish color (and maybe 10% of them turn amber), your plant is ready for harvesting.  

Track your crop with Grow with Jane

Would you love to track your crops and get to know how to report cannabis growing? The Grow with Jane app and platform is the perfect tool for planning and monitoring your crops. You’ll get a complete plant journal or Growlog with all your photos, data, reminders, and notes. All in one place.  


Harvest Cannabis at home

Your plants are finally ready, or that’s what you think. How to know when to harvest your marijuana plants? Just look at them and they’ll show you! 

When to harvest my marijuana plants

Pistils are those little “hairs.” They start white and as the plant ripens, they get darker and curling until they are brown.  Trichomes are little resin glands (that “frost”) and they also change color as they ripen.

Cannabis bud with white trichomes
Cannabis bud white trichomes. PH: caliz-sq

You’ll need a magnifying glass to see them properly, they look like lollipops. Trichomes start clear and transparent. When they become milky-white and some of them are amber, that’s the best time to harvest. If they are all amber / brown, it’s probably too late. 

Always look at your buds with a loupe or magnifying glass and look for:  

Pistils
  • 50-70% brown – young, light marijuana
  • 70-90% brown – ripe, heavy marijuana
  • 90-100% brown – sharp, heavy marijuana 
Trichomes
  • Clear trichomes – wait a bit longer
  • Milky white/amber trichomes – ready for harvest 
  • All Amber trichomes – overripe 

We prefer to look at the trichome evolution because it’s a more accurate method. Pistils may change color because of environmental modifications such as high humidity and not necessarily because the plant is ready to harvest. 

How to harvest Marijuana plants

Cut the plant at its base, then secure it (hanging upside-down) with a wire or similar. Cut the big fan leaves and keep the sugar leaves with trichomes. Trim your buds as desired before drying and curing.

How to dry Marijuana

Hang the whole plant to dry upside-down with a wire or similar, or hang the individual branches. Turn on a fan and aim it right beneath the buds, keeping the humidity around 45% and the temperature below 20º Celsius. Make sure the room is dark, and the extractor fan is running.  

The drying process may last 10 and 14 days. Look at them every day and make sure no mold is growing. If you find some, cut that bud and throw it away before it grows all over your buds.  

Exposure to oxygen and light causes THC degradation. To protect your precious buds, keep them in sealed containers, in a dark place, and below 20ºC. 

How to cure Marijuana

Keep those buds in glass jars or similar and open them once a day until they are cured.  

Don’t try to accelerate this process. Buds need time to dry and cure in order to increase the smell and bring out the flavors of the bud (terpenes). Curing affects the smell of the buds by breaking down chlorophyll, removing the taste of grass.