Jack Herer

In honour of the man and his work, Sensi Seed Bank was proud to give our premier marijuana strain the name Jack Herer. Over a decade since its release, the Jack Herer seed-strain remains one of our favourite creations, and has continued to win prizes at in cannabis competitions and harvest festivals all over the world.

This piece was originally posted on Google Knol. Knol will be discontinued from May 1st 2012, so this article has been moved to the Sensi Seeds website.

Jack Herer Cannabis StrainEvery friend of cannabis knows (or should know) the name Jack Herer.

Cannabis in all its forms –textiles, paper, food and medicine – has always been one of the world’s most important crops, but that knowledge was in danger of being collectively forgotten after decades of prohibition and disinformation.

Jack Herer’s book The Emperor Wears No Clothes and his tireless activism are among the driving forces of the modern hemp revolution that began in the early 1990s and continues to this day.

Mr Herer is a central figure in the movement to remind the world of the role that cannabis played in humanity’s most important developments. His book outlines the plant’s history and its potential to provide a sustainable alternative to many wasteful, polluting and destructive industries. He offers a compelling thesis on how cannabis can help save the world from approaching environmental crises.

The Jack Herer Strain
In honour of the man and his work, Sensi Seed Bank was proud to give our premier marijuana strain the name Jack Herer.

Over a decade since its release, the Jack Herer seed-strain remains one of our favourite creations, and has continued to win prizes at in cannabis competitions and harvest festivals all over the world.

At Sensi, we sometimes hear the rumour that Jack Herer is a difficult variety to grow. Growers who are considering cultivating Jack for the first time will sometimes ask us if this is so. We’d like to dispel that myth once and for all.

Apart from the normal considerations for growing a Sativa-hybrid – greater height-gain in flowering, longer flowering time, less need for high doses of nutrient – Jack Herer should present no problem to any grower with a some experience of indoor cultivation.

Perhaps the only circumstance where Jack Herer might not be a recommended strain would be a person’s very first try at indoor growing – in which case no Sativa-heavy variety would be suitable.

For growers who know the basics of indoor cultivation, for outdoor growers in warm and sunny climates and (especially) for growers who have mastered the art of cloning and maintaining their own mother plants, Jack Herer is an amazing strain that can delight and reward in equal measure.

Outdoors in a climate like Spain’s, Jack Herer can grow to the size of a small tree over the spring and summer, producing a large harvest that’s worthy of any outdoor plant.

Indoors, clones can be farmed intensively to produce great yields in small spaces. The height of Sativa-leaning phenotypes can be controlled by flowering very soon after rooting, and Jack Herer’s tendency to produce upward-growing branches means that plants often require less floor-space than Indicas and Skunks, whose lateral branches often compete for space.

Properly maintained mother plants will produce clones for years with no decrease in quality or vigour. In the first year or two, many growers notice that their maturing Jack Herer mother plants display steady increase in the quality of clones and potency of buds they produce.

Even among Sensi Seed Bank’s collection of powerful strains, Jack Herer’s resin-production is unparalleled. Trichomes cover the buds and the single-bladed leaves, and the thick resin coating continues downwards, bristling on the stem, even encrusting the outside edges of the five-bladed fan-leaves that are close to the internodes.

Looking at well-grown Jack Herer buds under a microscope, the green of the foliage is almost completely obscured by a forest of bulbous, clear-capped resin-glands. It is only from a normal distance that background green colour is reflected around and through the coating of resin.

Jack Herer represents both sides of the cannabis spectrum and is generally listed as 50/50 Sativa/Indica. Like most complex cannabis hybrids that bring together diverse gene-pools, individual Jack Herer plants grown from seed will lean slightly towards Indica or Sativa (within a certain range – none will be typical examples of either family).

Jack Herer has four main phenotypes, all of which display a mix of Indica and Sativa characteristics – even the tallest, longest-flowering Sativa phenos have larger calyxes and Indica density reinforcing their buds; the shorter, faster Indica phenos still possess a soaring high and often have Sativa ‘run’ to their flowers.

Growers should not expect uniform plants when growing Jack Herer from seed. One of this strain’s outstanding features is that it allows the grower to choose a phenotype whose growing pattern fits their needs and preferences, while maintaining Jack’s near-psychedelic potency in whichever phenotype is chosen.

When starting mother-plants from seed, many growers will take a clone or two from each plant as soon as it is big enough (25cm+), then flower those clones to determine the sex of the seed-plants they were cut from.
In this way, males can be discarded at the earliest opportunity and the original seed-plants need not go through the stress of being flowered, then turned back to vegetative growth after the females are identified.

Cloning and then flowering clones as soon as possible will also allow growers to get an early idea of the growth pattern and end-product to expect from each of the individual mother plants.

When working with Sativa hybrids like Jack Herer, clones can be put into flowering as soon as they have rooted. The tiny plants will gain height as they flower and will give an excellent preview of what their mother-plants will produce.

With this method, growers can have samples of mature bud representing each of their mother plants around the same time that those mother plants are big enough to start yielding large numbers of clones.

The most obvious distinction between Jack Herer’s phenotypes is whether their growth pattern is influenced more by Indica or by Sativa.
Beyond this, individual Jack Herer plants can be grouped into four main phenotypes. For easy reference, we’ll call them A, B, C and D. Each of the phenotypes displays highly desirable traits.

Phenotype-A (a personal favourite) displays strong Sativa characteristics in its growth and a sublime mix of running Sativa and fat-calyxed Skunk in its bud formation.

The buds of pheno-A take the form of long strings of inflated, highly resinous calyxes, very much like the Jack Herer pictured in the Sensi catalogue.
The strings of calyxes wrap around each other, snaking upwards, usually covering the top 50% of stem and branches by the end of flowering. Buds have a chunky, irregular form, with top colas ending in multi-crowned peaks.

Measure for measure, this is arguably the most potent of Jack Herer’s phenotypes, imparting an extremely powerful stone and high with immediate effect. The thick resin coating often gives it a sharp, almost menthol flavour.
If potency is the main aim, growers should select this phenotype, which can be reliably identified by its oversized calyxes.

Pheno-A requires the full 70 days to finish and can multiply its height by a factor of five or more – so it should be flowered very small (10-15cm), unless a large plant is desired.
Indoors, this pheno produces limited outward branching and can be a very efficient producer at a final height of 80-180cm.

Phenotype-B is the most Indica-influenced. It is very compact when compared to other Jack Herer phenotypes, though significantly taller than a pure Indica.
It adds about 100-200% to its vegetated height in flowering and finishes in under 60 days.

Growers who have a particular interest in speed, weight and compact growth pattern should select Jack Herer’s pheno-B as a mother.

Buds mainly cluster around nodes, but ‘run’ enough to cover a large portion of the (shorter) stem and branches. Flower formation is dense and regular, forming angular knots with blunt peaks.
Upper branches often combine with the main stem to forma large central cola. Calyxes are large, but not oversized, pistils are relatively short;.
Indoors, this pheno produces most efficiently at a height of 50-100cm.

Pheno-B has a strong Indica effect, which may be the first noticeable result of consumption , but it does not overpower the cerebral Sativa effect which should creep up soon afterwards.

Pheno-B usually has a distinct aroma – citrus-sweet with piney undertones.

Phenotype-C is also heavily Sativa-influenced, and some growers might consider it to be the same as pheno-A, with which it shares many growing characteristics such as flowering time (70 days) and height gain (300%+ of vegetated height).

There are a few differences that allow C to be considered a separate phenotype. It produces swollen calyxes, but they are significantly smaller than those of pheno-A.
These calyxes also grow in strings –outwards as well as upwards – and produce long pairs of pistils, which give the buds of pheno-C a spiky appearance.

The budding pattern of pheno-C has plenty of Sativa ‘run’ to it, and the fact that the buds also develop outwards means that C will generally produce the largest buds the four phenotypes. This extra size may not greatly increase the overall yield, as these flower clusters are a little less dense than the others.

All in all, pheno-C most resembles NL#5xHaze in formation, flavour and effect. It has voluminous, fuzzy buds with a sparkling coat of resin, a delicate aroma that’s spicy-sweet, acerbic yet almost creamy, and the most energetic ‘up’ high of Jack Herer’s variations.

Phenotype-D (another personal favourite) might be regarded by commercial growers as the least desirable in terms of its growth pattern. Like an Indica it produces dense knots of bud of at each node and like a Sativa it gains quite a lot of height during flowering. This often results in gaps between nodes below the top colas.

The main advantage of this phenotype is that it produces truly spectacular amounts of resin – enough to give the buds an obvious silver colouring after the mid-point of flowering. In terms of weight of bud/plant matter vs weight of resin (as extracted with the water-hash method), examples of pheno-D are some of the most resinous plants we’ve ever seen.

Despite its lower yield, many growers will choose to reserve a corner of their space for the growing of Jack Herer’s pheno-D purely for its resin content.

Pheno-D tends to produce very limited branching and clones can be grown close together without interfering with each other. Indoors, it is most efficient when kept to a size of 30-80cm. Flowering time is comparatively fast – usually 60 days or less.

Jack Herer’s phenotype-D has a sharp, rich flavour, similar to fresh hashish. It’s generally the pheno with the most obvious physical ‘stone’ effect.

Spending some time to select the appropriate Jack Herer mother plant will enormously increase the grower’s potential for long-term success. Of course, this is true when selecting any mother plant.

The notable advantage of Jack Herer is that every female in a packet of cannabis seeds will be a potent, high-quality plant.

With careful selection, a grower can find and preserve the Jack phenotype which ideally suits their taste and situation. Selecting a suitable plant and working with it for consecutive harvests will allow any grower to consistently produce world-class Sativa cannabis the same ease as a crop of Super Skunk.

» Click here to buy the Jack Herer strain in our webshop



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I Live in the USA. and have my license to use medical marijuana. Just recently, it was past in my state, to . use marijuana by the general public for personal use. The state of Colorado and Washington are among the first to open that door. It would be great if our government will honor our Constitution and allow the individual states to rule for them self's as stated in our Bill of Rights and our Constitution. With that thought the drum beats on.
Thanks for your time and help.
Vaya Con DIOS



I thought this was a very informative as I hope to grow JH (Rip) in the next year or so. Finding out there are four different pheno's and having them described in such detail is great. This will save any serious grower a lot of time. I was going to get 5 pips but after reading this I will have to get 10 to try and sample the full array of this strain. I cant wait to get started on them, but first I got to try making some oil. Mr Simpson's receipe.



From the uk whats the max indoor temp for jack/ blues please


Ben Sensi

Hello Strut,

For any grow question we would recommend you to go visit the Sensi Seeds forum.

Thank you.

All the best,


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