What are heirloom cannabis seeds?

Cannabis has been used for millennia, but cannabis as we know it today has only really been around for half a century, or less. Despite the thousands of strains on the market today, these all originated from relatively few pure and natural cannabis strains.

Though hard to come by, these strains can still be found and grown today—and are known as heirloom cannabis strains. In this article, we investigate exactly what these are.

What are heirloom cannabis seeds?

Heirloom marijuana seeds, or heirloom marijuana strains, are those that have passed their genetics down from generation to generation, without cross-pollination changing them. For those familiar with the basics of cannabis varieties, you might be thinking that these sound similar to landrace strains—and you’d be right! We’ll get into the distinction shortly.

Heirloom cannabis is more or less unchanged compared to how it was when it was first discovered, collected, and bred. Indeed, remaining genetically unchanged is key to a strain truly being “heirloom”. Of course, each individual plant will have its own, unique genotype, but this will be the result of natural mutations, rather than crossbreeding with a distinctly different cultivar.

As heirloom strains haven’t been deliberately crossbred with other strains, they can be described as non-GMO plants. These strains are the product of generations of open-pollination; that is, pollination as a result of natural breeding. In time, strains in certain regions of the world stabilised to create landrace, or heirloom, strains.

Cross-pollinated strains, on the other hand, are human-made hybrid cultivars—which are far more readily available on the market.

Are heirloom seeds organic?

Heirloom strains are not necessarily organic. Organic refers to how something is grown; if it is grown without synthetic fertilisers or pesticides, then it may be classified as organic. Simply being of a more natural origin, as heirloom cannabis seeds are, does not indicate that they are organic.

Heirloom vs landrace cannabis

So, what is the difference between landrace and heirloom strains?

Landrace strains can be thought of as the original cannabis strains. For instance, a wild Thai strain is a pure landrace. Heirloom strains, on the other hand, are those cultivated out of the wild.

The distinction has less to do with genetics and more to do with how they are grown. That being said, a true landrace will essentially be “wild”, or at least pollinated through open-pollination, whereas heirloom strains are carefully bred to maintain stable genetics.

Although the terms are distinct, they are often used interchangeably, with some seed banks offering “landrace” seeds that are in fact heirloom seeds.

Why are heirloom seeds important in the cannabis scene?

Heirloom seeds have cultural, historical, and breeding significance.

Culturally and historically, these were the first cannabis seeds used to cultivate cannabis in Europe and North America—as we know it today. Prior to this, cannabis was still grown and used, but in a very different way.

Made famous in the 60s and 70s, travellers would bring back cannabis seeds from their travels. These landrace seeds formed the basis for pretty much all modern cannabis seeds. Perhaps the most important landrace strains are:

• Cambodian
• Nepalese
• Thai
• Swazi Gold
• Durban Poison
• Hindu Kush
• Afghan Kush
• Afghan
• Acapulco Gold
• Colombian Gold
• Pure Red

From these pure landraces, hybrids were bred, which were then crossbred and so on, giving us the myriad cannabis strains we have today. Therefore, for cultural and historical purposes, landraces/heirlooms have great significance.

But they also still play an important role in modern breeding. These strains, being pure, are incredibly stable. Cross two together and you get another plant that's very similar. Cross two hybrids together, and you might get something brand new. This means that using heirloom strains in breeding is still a useful practice.

Finally, as the phytochemical profiles of heirlooms generally aren’t tampered with, the plants tend to have lower THC concentrations and higher CBD concentrations than many popular strains. The effects of these strains are generally considered gentle compared to modern ones. Regardless, they offer a distinct cannabis experience from the vast majority of other strains.

Are heirloom strains better than modern strains (hybrids)?

Not at all; it simply depends on what you’re after. As mentioned, heirloom seeds tend to have milder effects, which can be positive or negative. Likewise, don’t expect monstrous yields from heirloom seeds, though that’s not to say all heirlooms are poor yielders.

Are heirloom strains harder to grow than modern strains?

Modern cannabis strains are optimised to grow well; to be robust, resistant, and fruitful. Heirloom strains, on the other hand, have developed naturally, and as such can be a little more difficult to grow, especially out of their natural habitat.

A Thai landrace may grow well in Thailand, but a Thai heirloom could struggle outdoors in, say, the UK. So if you’re going to grow an heirloom strain, bear in mind that they thrive in the conditions that their ancestors evolved in—so try to imitate these!

Where to buy heirloom cannabis seeds

Heirloom strains can be hard to come by—genuine heirloom strains even more so.

The most commonly available are probably Kush strains and Durban Poison. Check out Zamnesia for a selection of heirloom strains. Otherwise, heirlooms are available, but make sure you buy them from a reputable seller, otherwise you might end up with something that just claims to be an heirloom seed!

Which heirloom varieties are the best?

It's hard to say which heirloom varieties are the “best”, as it all comes down to preference. That said, we’ll share two strains that are considered classics, and that display distinct morphological traits. Note that not all strains labelled as the following are true heirlooms.

• Thai: For a pure and original hit of sativa, consider trying a Thai heirloom seed. These have long flowering periods and like warm environments. In return, they offer a truly energising buzz.
• Afghan Kush: Alternatively, for a classic stone, why not try Afghan Kush? This variety grows lower to the ground and more compact, and is a little hardier. For novice growers looking to grow a classic, you can't do much better than these genetics.

Whichever you choose, make sure you purchase from a reputable seed bank, otherwise what you're getting might not be a true heirloom cannabis seed.

Heirloom cannabis: The origin of many popular hybrids

The genes of heirloom cannabis strains are present in essentially every modern cannabis strain on the market—at least the ones we smoke. So it’s safe to say that they are fairly important, and without them, the cannabis world would be a very different place.

For many, it’s enough to know these strains exist, and the role they have played in creating the exceptional hybrids of the modern era. For those who want to try growing and consuming their own heirlooms, however, do your due diligence and give these special plants the care they deserve!