This article includes everything you need to know about genetics and breeding various types of seeds and strains as well as growing indoors versus outdoors.

Cannabis as Medicine

The first known use of marijuana as medicine traces back to around five thousand years ago when a Chinese botanist prescribed it as a cure for malaria, beriberi, constipation, rheumatic pains, lack of concentration and several female specific ailments. It was used medicinally throughout the ages by various civilizations until the stigmatisation that came with prohibition as well as improvements in modern medicine in the mid 1900’s.

Fast forward through a few scientific breakthroughs to the 1990’s and the use of medical marijuana once again became increasingly popular in the Western world. It is even purchasable in pharmacies with a simple prescription. Despite decades of criminalization all around the globe the world is waking up to the vast medicinal value of this fascinating plant and legislation is following suit. Now days it is becoming legal to use Cannabis as medicine but also to grow your own from seed at home.

Genetics and Breeding

The Breeding Process

Genetics play a key role in determining the physical characteristics of all species and the plant kingdom is no exception. Plant breeders generally seek to understand and master genetics in order to favourably impact the outcome of the harvest influencing factors such as growth characteristics, yield size, disease resistance, colouration, chemical profiles and overall size and quality of the fruit or flowers.

Breeding any plant, cannabis or other involves the same basic process. Normally a female must be pollinated by pollen from a male. This happens naturally when males and females are grown together or via hermaphroditic plants with both sex organs (self-pollination). However in order to promote favourable traits breeders cross pollinate strains by carefully selecting the female plant and the male pollen in order to create genetic hybrids.

The Quest for Stable Genetics

“Stability” is a word often used in the same breath as genetics. We say a strain is stable when it has a high level of predictability when we are able to predict the characteristics of the plant. We say a strain is unstable when it exhibits greater variability. The more unstable a strain is the less we are able to predict what characteristics its offspring will portray. Why do we want seeds with stable genetics? Simple when you purchase cannabis seeds of a specific strain you want to know that your seed will produce a plant that displays all of the characteristics true to that strain.

Seeds that result from hand selecting and cross breeding male and female parents are called first generation hybrids. These “F1 hybrids” will be the most stable of the hybrids to follow. The offspring are called “F2 hybrids” and those that produce the desired traits will be bred again. This occurs either through inbreeding (crossing two F2’s that display sought after qualities) or back crossing (crossing an F2 offspring with an F1 parent). As the process continues F2’s become F3’s, F4’s and so on. One can even create “polyhybrids” by crossing two F1 hybrids of separate lineages.

Breeding is a patient practice, often occurring over three to four generations and involving technical processes like “squaring”, “cubing”, “trait fixing” and “selfing”. Though there are many trade secrets the overall goal is always the same to achieve stable, homozygous genetics that repeatedly display favourable traits. Keep in mind that the environment in which a plant grows plays a major role in how the plant turns out with significant regards to the production of therapeutic compounds such as cannabinoids and terpenes.

Old School vs. New School

All modern day strains can be traced back to a handful of marijuana plant types. In fact botanists can trace the entire cannabis lineage back to an original strain from the Hindu Kush mountainous region of Afghanistan and Pakistan. Over time humans have transported and cultivated marijuana all around the globe. Strains that have become indigenous to particular geographic regions and have not been crossbred with other varieties are known as landrace strains. They have remained untouched by anything other than nature.

Landrace strains are often referred to as “old school” genetics. According to the Collins English dictionary a landrace is “an ancient or primitive cultivated variety of a crop plant”. True to their name these strains are the tried and tested true legends of the cannabis world. Most are named after the country or region in which they have adapted to grow naturally such as “Afghan Kush” or “Durban Poison”. Descendants from landrace strains are often proud to bear part of the region’s name such as “Purple Afghan Kush” or “Lemon Thai Kush”.

Importantly the landrace classification is by no means an indicator of quality. It simply describes a strain’s genetic purity and indigenous upbringing. Landraces are closer to the original wild species than anything else we have available today and are thought to be important for breeding purposes as have been “chosen” or moulded by nature. “New school” genetics describe strains that have arisen in more recent years. They are the result of cross breeding older genetics to create favourable qualities such as heavy yields and resistance to mold.

Strain Types

Sativa & Indica

The classification of strains can be a little cloudy. According to contemporary botanical definitions Cannabis Sativa refers to the modern day low THC “hemp” plant while Cannabis Indica describes what we refer to as “Indica” (Cannabis Indica ssp. afghanica) and “Sativa” (Cannabis Indica ssp. Indica) today. In other words what we currently describe as Sativa and Indica strains are technically subspecies of C. Indica while hemp is a separate variety as are Ruderalis and Hybrid strains (discussed further down).

According to Jean Baptiste Lamarck a renowned French biologist from the late 18th to early 19th centuries C. Indica and C. Sativa adopted distinct characteristics in terms of their appearance and the effects caused when ingested.  He noted that the physical characteristics of Indica were evident in shorter and stockier plant structure as well as shorter, wider leaves. In contrast Sativa plants tended to grow taller and slimmer with longer and thinner leaves. An important consideration is that Lamarck would have been describing distinct Sativa and Indica strains of far purer genetics than the mixed Hybrids we know today.

In terms of the effect caused upon consumption Sativa strains are believed to be uplifting, mood enhancing and more apt for social settings whereas Indica strains are thought to be calming, sedating and good for stress relief and pain. However we now know this to be untrue as the genetic makeup of a strain is not a reliable indicator of its effect. When it comes to aroma, modern day marketing strategies lead customers to believe that Indica strains emit musty, earthy and Skunky odours, while Sativa's smell sweet, fruity or spicy. Aromatic and flavour differences result from variations in terpenes and flavonoids which are distinct plant compounds from cannabinoids (like THC and CBD).

Indica is believed to have evolved in the Middle East in places such as Afghanistan, Pakistan and Tibet whilst Sativa is understood to stem from warmer parts of the world such as Southeast Asia as well as Central and South America. Being larger Sativa plants require more time to grow yet allegedly yield less than Indica varieties. The bottom line is this there exists little scientific evidence behind the claimed differences and perceived effects of these two strain varieties. While genetically pure “Indica's” and “Sativa's” may have had distinct effects and differences many years ago most available strains nowadays are Hybrids.


There is debate amongst botanists but ruderalis is thought to be a unique sub species of cannabis. What we know for sure is that it is a wild or “Ruderal” type of marijuana that thrives in even the harshest conditions. This strain type was first officially and scientifically identified in the wild regions of South Siberia in 1924 by Russian botanist Janischewski. He then started referring to all cannabis varieties that grew wild with no human intervention and in extreme weather conditions as Ruderalis.

These plants tend to be smaller and stockier than Sativa and Indica varieties along with wider leaves. The main feature that sets Ruderalis varieties apart is their ability to flower automatically as soon as they mature after a set number of days regardless of the photoperiod (amount of light) that they receive. Hence modern “auto flowering” strains have been bred with ruderalis genetics for speedier yields.


A hybrid is simply the result of any two strains that have been bred together. They usually contain a mix of Indica and Sativa genetics (plus Ruderalis for autoflowering varieties) and depending on the lineage an offspring can display characteristics of both parent strains. There is no set rule when it comes to breeding Hybrids. Any Sativa, Indica and Ruderalis strains can be crossed at the will of the breeder. The resulting strains are described as either balanced or Indica or Sativa dominant meaning they predominantly express the characteristics of one parent over the other.

Hybrids offer a great opportunity for medical marijuana patients who need to use products throughout the day and seek tolerable and “balanced” effects. In fact medical cannabis products make use of strains with varying cannabinoid ratios from high THC to balanced to high CBD. Notably thanks to the emergence of Hybrids high CBD seed varieties that contain just enough THC to enable the “entourage effect” are now readily available.

Types of Seeds

Regular vs. Feminized

Regular seeds operate in the way that nature intended untouched by human interference. When planting regular seeds you are taking a fifty-fifty gamble. Half of your crop may turn out to be flower producing females and the other half may grow into pollen producing males. For the everyday home grower seeking hefty yields of resinous bud males are an obvious issue. For breeders however males are a vital part of the process. Hence without regular seeds breeding would be impossible. Regular seeds have another advantage in that they tend to make superior cuttings which are hardy and tolerate stress well.

Feminized seeds have been bred with a modified genetic makeup to ensure that each seed produces a female marijuana plant. In other words every plant will produce harvestable, sticky, resin covered buds without fear of pollination by males. The allotted space for growing will be maximised as every seed all but guarantees the production of sensimilla (potent, seedless marijuana). Growers that have no intention of breeding usually prefer feminized seeds as they are guaranteed a viable crop without the worry of hunting out the males. Now days reputable suppliers ensure stable feminized genetics eliminating the fear of hermaphrodites when cloning mother plants.


Auto flowering plants are considered “day neutral” and are triggered to flower by an independent mechanism. This variety does not flower according to the periods of light and darkness to which it is exposed. Instead flowering is dependent on the age of plant. As mentioned earlier autoflowering genetics descend from wild Cannabis Ruderalis populations that evolved naturally in Eastern Europe, Russia, China and elsewhere in central and northern Asia.

As with other marijuana types the botanical classification of C. Ruderalis is contested. Some botanists classify auto flowering cannabis as a species in its own right while others argue that it is a subspecies of C. Indica or C. Sativa. Many growers consider auto flowering seeds for outdoor grows as they lead to much faster harvests need less specific care and can withstand harsher environments. They do however tend to produce a smaller yield due to the shorter growth phases.


It is no exaggeration to say that high CBD cannabis is the foundation of the medical marijuana world. CBD (cannabidiol) is a highly therapeutic marijuana plant compound that is non psychoactive meaning that it does not cause the famous “high” or intoxication normally associated with the plant. Research into CBD has discovered that the human body has what is called an “endocannabinoid system” which regulates basic bodily functions such as mood, appetite, pain, memory, inflammation, neuroprotection, movement, temperature, digestion and sleep.

CBD works by activating or blocking neurochemical receptor sites (CB1 and CB2) in central nervous system and throughout the body in order to help deal with symptoms like chronic pain, stress and nausea. It is a proven anticonvulsant for the treatment of epilepsy and seizures and even has the potential to fight cancer. Dinafem Seeds is known for their stable, high quality, therapeutic CBD strains, like Dinamed CBD. These were deliberately created so that people can safely grow medical cannabis at home with the assurance that every successfully germinated seed will grow into a plant with a high CBD concentration.

Of course high THC strains and those with balanced CBD:THC cannabinoid ratios have their place in the medical world too. You can read more about all marijuana compounds in Medical Cannabis 101 or focus on the medical marvel that is CBD Oil.

Indoor vs. Outdoor Growing

Indoor Cultivation

Growing indoors relies on the use of powerful artificial lights to replicate the effect of the sun outdoors. In the early stages of life seedlings are happy to start with lower light intensities often a metre distance below an HPS light or closer to fluorescent lights. The artificial lights normally remain ‘on’ for 18-24 hours per day. During this stage, the plants are in a “vegetative” state growing roots, leaves and branches but no buds. Once switched over to a 12 hour light, 12 hour dark cycle the plants will enter the “flowering” phase.

Growers often prefer indoor cultivation to growing outdoors as they have far more control over the environment. An indoor setup can be basic (soil, pots and a light) or incorporate more sophisticated and expensive equipment like air purifiers, dehumidifiers, hydroponic systems and CO2 generators. Plants are less exposed to the elements (such as wind, cold and humidity) and generally less susceptible to pests and mold (if conditions are managed properly). The main advantage to an indoor grow however is the ability to grow quality cannabis all year round irrespective of the season.

Outdoor Cultivation

Outdoors plants follow a dedicated growing season determined by regional weather.

Generally the natural grow cycle is as follows: 

  1. Seeds that have fallen and planted themselves into the ground begin to germinate in the spring time.
  2. Marijuana plants vegetate right through the summer as long as there is plenty of sunlight.
  3. As autumn nears and days get shorter the plants enter the flowering phase females produce flowers and males produce pollen.  
  4. Males pollinate females in order to produce seeds.
  5. The plants dies off in winter dropping seeds to the ground which await spring time. The annual cycle then repeats itself.

Of course the cycle is made more efficient with human intervention. Outdoor growers often begin sprouting seeds indoors earlier in order to get a head start on the season with the hope of a heftier yield. Some growers prefer to use feminized seeds but this can come at considerable cost. Many growers use regular seeds meaning they have to remove out males in order to avoid pollination and the resulting seedy buds. Supplemental lighting and phase appropriate nutrients are commonly employed.

There are pros and cons to both methods. Indoors setup costs can become pricey, as can electricity bills. Though it is stealthy and the ability to control the environment can result in huge yields. Outdoors it is easy to let nature take its course and costs are limited. Yet growers do need to worry about factors like nosy neighbours, theft, pollination and various pests and fungi.

The Bottom Line

While cannabis laws have relaxed enough to allow for plants to be grown as a hobby at home the limits are tight and the consequences of breaking them immense. The line between growing legally and potential jail time could be as little as a couple of plants. Recreational users who do not overindulge have good reason to be happy. Those needing marijuana for medicinal purposes however most likely would not be able to maintain a necessary supply.