Tips to select the best cannabis genetics for greenhouses

Tips to select the best cannabis genetics for greenhouses

A common comparison I like to make between autoflower and photoperiod cannabis types is determinate versus indeterminate tomato types. While indeterminate tomatoes can be advantageous, the advantages of the concentrated harvest timing and vigorous growth of determinate tomatoes are enough for many growers to choose determinate varieties. In cannabis, the advantages of not having to use light-deprivation techniques to cause plants to flower at a certain size that works well for a greenhouse setup can be a huge cost saver and can help to avoid pitfalls in light deprivation like equipment malfunctions that commonly lead to hermaphrodite plants.

Hermaphrodite plants can easily seed across a greenhouse, making a crop very challenging to sell. Both hemp and cannabis are available in autoflower and photoperiod type seed.


As cannabis breeding advances, feminized seeds of both autoflowering and photoperiod types of cannabis are becoming increasingly popular due to their ease and vigor.
Photo courtesy of Humboldt Seeds

Understanding Your Plants

Cannabis is most often dioecious, meaning that male and female sex organs are expressed on completely different plants. Commonly, cannabis that's grown for its cannabinoids will be entirely female to avoid the plant putting energy into seed and to avoid the seed altogether, as it's unpleasant to smoke and can reduce yields in chemical extractions.

Hemp fiber and hemp grain producers may have crops consisting of both male and female plants. The male cannabis plant produces flowers that release huge amounts of pollen and appears very different than the commonly known female bud form of the plant. You can check out Humboldt Seed Company's YouTube channel or HumboldtSeedCompany.com for amale versus female cannabis training video called "Determining Sex at Four to Six Weeks." We created this video years ago, and while it was not a high-budget production, it is still one of the most popular videos on our site.

Occasionally, cannabis can express monoecious characteristics, otherwise known as hermaphrodites, where male and female sex organs appear on a single plant. This is common in hemp varietals that have been bred for fiber or seed but should be strictly avoided in all other cultivation plants.

In their natural form, cannabis seeds will produce both male and female plants but techniques can be utilized during the breeding of cannabis that will render 99% of the seeds to be female. These are commonly referred to as feminized seeds.

Rooted cuttings, also referred to as clones, are one of the most popular ways people propagate cannabis, although the costs associated with the production of clones and the propensity of clones to carry disease or pests is high.

Tissue culture is another way to propagate and avoid the pitfalls of disease and pests, but the costs associated with tissue culture can lead to companies putting genetics through tissue culture as a clean-up and then going back to normal clonal propagation. This often will still be referred to as tissue culture cloning.


Consider the needs and preferences of your marketplace when choosing a cannabis strain. 'Blueberry Muffin' is an indica-dominant strain with a flower cycle of 45 days that can be grown in the greenhouse. The buds smell like blueberry muffins.
Photo courtesy of Humboldt Seeds

Choose Your Genetics and Supplier With Care

As cannabis breeding advances, feminized seeds of both autoflowering and photoperiod types of cannabis are becoming increasingly popular due to their ease and vigor.

Commonly, the sativa type of cannabis is associated with a thinner leaf structure and is recommended for more humid tropical or subtropical climates, and the indica type of cannabis is recommended for cooler, dryer conditions. I have not seen this correlation to be true as much in practice as it is rumored to be, and the growing environment inside a greenhouse can easily be adjusted for the plant's needs

In short, it is more important to choose a strain that has features that will please the marketplace than to draw lines based on the breeders sometimes arbitrary determination of Cannabis indica or C. sativa and C. ruderalis. Traits simply refer to autoflowering these days, and should no longer influence the quality of the end product, as breeding has improved in the last five years.

Selecting a seed company can be challenging, as there are many, and state laws can be tough to navigate and understand regarding genetic acquisition. It is very important to establish trust when selecting a breeder or genetics source, and great breeders and nurseries are often very busy with clients, so it's important to be patient and willing to compensate these businesses for their time. As the industry grows and evolves, with scale being the big question, what genetic to select will become a much simpler process. For now, this important stage in your growth may warrant some time and preparation so you don't plant before understanding what it is that you're growing.

Source and Photo Courtesy of Greenhouse Grower

Source: Greenhouse Grower

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