Cultivars, Chemovars & Cultivation

Breeds (Cultivars)

Cultivars are breeds of a plant species bred for different purposes. Cannabis and Hemp are just different cultivars of the same plant. They are legally defined by the content of THC present in them. 

Cannabis > 0.3% THC (Tend to be used for medicinal or recreational purposes)

Hemp < 0.3% THC (Tend to be used for industrial or food-based purposes)

 

The Rise of Chemovars

The terms Sativa and Indica were introduced in the 18th century to describe the different species of Cannabis. The Indica species was shorter in stature and had broader leaves. The Sativa, on the other hand, was taller in stature with narrower leaves.

The different Cannabis strains are usually classified as a derivative of one of the two or as a hybrid.  Though popular in Cannabis culture, this kind of classification holds no scientific validity firstly, because the terms “Indica” and “Sativa” are not scientifically recognized. And secondly, because these strains have been interbred several times that the original Indica and Sativa can no longer be distinguished.  The term ‘Chemovar’ (short for chemical variety) is gaining more traction as it differentiates the plant-based on its constituents (Cannabinoids, Terpenes, and Flavonoids).

 
Differences between the traditional Sativa & Indica terminology
Source: Leafly

 

Seed to Harvest

Understanding the life cycle of the plant, the changes it undergoes and the care needed at different stages are important factors to consider. Different stages need different amounts of light, nutrients, and water. Regulating temperature and humidity also play a critical role here.   

  1. Germination (week 1-2) - Sprouting of hard dry seeds by soaking with paper towels.
  2. Seedling (week 2-3) - Transfer of seeds into a growing medium with the right amounts of water.
  3. Vegetative (week 2-8) - Plants are provided all the essentials and more nutrients to grow well. Male and female plants are separated before pollination to prevent the female plants from producing seeds instead of trichomes.
  4. Flowering (week 6-12) – This is the stage where the properties of the flowers can be moulded by different techniques like light deprivation.
  5. Harvesting - The flowers are trimmed, dried and cured.

Note – Hemp grown for fibre is harvested before flowering.

 

Grow Methods

This is the site where Cannabis is cultivated.

Indoor: It is the method of growing Cannabis in a controlled environment where the plant is not exposed to the outside environment. This allows growers to have complete control of the process and conditions which can be regulated to optimise yield and get a cleaner Cannabis. It can also be grown all year round. In saying that, the plant is deprived of natural sunlight and the conditions outdoor which can reduce the plant’s terpene profile.

 
Indoor cultivation site
Source: Hightimes

 

Greenhouse: This is a sun-grown method with provisions to block out sunlight (light deprivation) that tricks the plants into flowering faster. Natural sunlight enables the yield to have a full terpene profile. The ecological footprint is also smaller when compared to the indoor grow. The growers need to work around the external conditions and the yield is more seasonal.

 
Cannabis Greenhouse
Source: Leafly

 

Outdoor: This method is the most natural and the least expensive way to grow. Natural sunlight allows the plant to attain a full terpene profile but exposure to the elements could also have a detrimental effect on the quality of the flower.  

 
Outdoor farm
Source: Hightimes

 

Grow Techniques

The following are different techniques used by growers through the life cycle of the plant.

Soil Grow: This is the traditional form of growing where the plant is grown in the soil. This offers the stability that natural and organic growers appreciate. The roots of the plant absorb the nutrients from the soil. Good soil mixes have all the essential nutrients for the development of the plant.

Hydroponics: It grew in popularity for Cannabis cultivation in the 1960s and 1970s as a way to grow indoors. This is a method of growing plants without the use of soil. The plant roots are suspended in a medium such as (sand, gravel, water, etc) and a nutrient-rich solution is directly applied to the roots. The water that is unused is recycled through the system for the roots to absorb them later. It allows for greater control and automation for the grower.

Aeroponics: This is a unique version of hydroponics where the nutrient-rich solution is sprayed as a fine mist into the chamber where the roots are exposed. The highest oxygen percentage can be introduced because the roots are not continuously soaked up in the water. These are costly to set up but allow for maximising grow space as it allows for vertical growing.

 

Hydroponics (left); Aeroponics (Right)
Source: Leafly

 

Further Reading:

Research Paper - From Cultivar to Chemovar - https://www.researchgate.net/publication/270572395_Cannabis_-_from_cultivar_to_chemovar

5 Cannabis Breeders who changed the game - https://www.leafly.com/news/strains-products/cannabis-breeders-who-changed-the-game

Cannabis cup - https://www.cannabiscup.com/past-winners/so-cal/2018