Critical Jack Strain

This Critical Jack strain has been created from two of the most legendary strains, giving you a  top-quality hybrid. Derived from Critical Plus and Jack Herer, this bud gives you a pleasant high which you can experience at any time of the day or night.

It is also a strain that is said to not trigger that dreaded cough or a hard high, making this a great bud for beginners to get comfortable. It doesn’t end there.

This strain is also said to have some great medical qualities, such as easing chronic pain, preventing nausea, and helping to increase your appetite. It also has mental benefits such as giving users a clearer head and helping them maintain concentration! 

Are you looking for a high that won’t leave you stuck on your couch for hours? Have you been experiencing chronic pain and just want to experience some relief?

Keep reading because this product may just be the perfect one for you.

Critical Jack Strain

Strain History 

 This hybrid mix between Critical Plus and Jack Herer is so good it has even won a couple of awards. It won 1st prize in the “Outdoor Sativa” category at the UCLA cup and it has been awarded 1st place in the “Best Shatter” category in the 2015 San Bernardino Hempcon Cup, USA.

This really shows the quality of this strain. It typically carries a THC level of around 20% and usually leans towards the Sativa side but this depends on the individual grower. Whether it falls under the Sativa or Indica side determines what kind of high you are likely to experience.

For example, if a bud is leaning more towards Indica, like the Blackberry Cream strain, then this will give you more of a full-body high such as deep relaxation and reduced insomnia.

However, If a strain is higher in Sativa, they are more likely to give you a head high, and energizing effect that helps to reduce anxiety and can increase creativity and focus, which is exactly what this Critical Jack strain does. 


This successful bud has its parents to thank, Critical Plus and Jack Herer. Critical Plus is also a hybrid between Skunk and Big Bud, who won the first Highlife Cup in Barcelona. It carries an aroma of citrus and skunk, with a lemon and lime flavor.

Critical Plus is a mood enhancer, giving a head high with a relaxing body buzz. This is great for treating depression, anxiety, PTSD, and migraines. Elements such as the mood enhancer and head high have been taken from Critical Plus’s genetics, to create Critical Jack.

With this strain’s other parent, Jack Herer, the exact formula is kept secret, but it is thought to be a mix of Haze, Northern Lights #5, and Shiva Skunk. This strain carries an orange-lemon scent and taste with a hint of some dark pine.

Jack Herer, a strain that went on to win 9 cannabis cup titles, also carries euphoric, uplifting effects while increasing creativity and productivity. It is a strain that is known for facilitating a clear head.

These are aspects that have clearly been used to create Critical Jack. It’s safe to say that we are onto a winner here with the best genetics from these two very well-known strains being used to create Critical Jack. 


 The Critical Jack strain originated in Spain, with Dinafem seeds as their breeder. They are a seed bank that sells both Sativa and Indica seeds on the market.

They have produced their own seeds after carrying out research on the genetic characteristics of cannabis plants. It’s safe to say, they know their stuff!

In order to create Critical Jack, they cross-pollinated their own Critical Plus with a Jack Herer strain from Sensei Seeds, another seed distributor, in order to create this wonderful composition from two icons.

This strain is said to produce a long-lasting balance of a head buzz that energizes and enhances productivity, along with relaxing, warm fuzzy body effects that don’t leave users feeling sluggish or immobile.  

Strain Appearance 

This plant will grow to a medium height. Its structure is open with branches to allow lots of light and air to get through to the buds which generates a thick layer of trichomes. 

Strain Flavor 

This strain delights us with an intense, sweet taste. It carries a floral flavor, with hints of fruit and pine. It appears to have taken the genetics from its parents with the fruity citrus taste from Critical Plus, along with Jack Herer’s dark pine flavor. These combinations allow for a wonderful hearty mix that is truly irresistible. 

Strain Aroma

Before you even taste this bud, you are already mesmerized by its intense aroma. A blend of lemon, pine, and floral smells are what surrounds this strain, resulting in an exquisitely pleasant experience overall. 

Strain Cannabinoids  

This strain is dominant in THC, at  20 to 22%. Its CBD is at  0.64- 0.88%. 

Strain Terpenes 

 The most prominent terpene in Critical Jack is Myrcene. This carries an earthy musty note with a fruity, grape-like aroma. Strains that contain this terpene usually have sedative effects, which would explain the relaxed buzz this strain gives off. This is followed by Pinene and Terpinolene.

Pinene is well known for its smell resembling pine forests. It can also be found in certain herbs such as dill and parsley. This is a refreshing scent, quite woodsy and earthy. Terpinolene has more of a floral aroma.

Just reading these lovely combinations will really show you what a lovely fragrance and taste this bud has. 

Strain Side Effects 

This strain may leave you with dry eyes, occasional dizziness, and a thirsty dry mouth. If you are experiencing any of these when using this strain, be sure to drink plenty of fluids in order to stay hydrated. 

Effects may vary from person to person, but users are reminded to be sensible in the way in which they approach marijuana to avoid any negative outcomes. 

Medical Benefits 

Critical Jack’s uplifting and mood-enhancing properties make it a popular remedy for depression, headaches, and appetite loss. This would be great if you’ve just been battling a stomach ulcer where you lose your appetite.

The enhanced appetite benefit would also be useful in helping anyone who has struggled with eating disorders as it not only aids in increasing your appetite, it also helps fight against nausea.  If you are experiencing headaches or migraines,  this strain could help clear those right up!

As well as relieving headaches, this bud is also known to have a pain-relieving effect in areas such as muscle pain and spasms, chronic pain, or any other aches your body may be feeling.

Jack Herrer

Strain Review 

The most prominent feedback from Critical Jack was how clear-headed people felt after smoking. Some even stated they felt more of their creative juices flowing and were able to complete tasks they had been putting off for weeks!

Users stated they felt relaxed but not sleepy so they were able to get on with their day-to-day lives. It was reported that this strain’s effects are light on the body and stimulating to the mind.

It was said to have allowed people to focus on one task at a time without getting distracted like they normally would, or allowing emotions to get in the way. Many reviewers relished the increase in appetite it gave them.

Overall, this product gives off more of a mental high than a body high, due to the fact it is a Sativa product and not an Indica.

Although this strain does have a relaxation effect, it does not leave users feeling heavy, sedated, or sluggish,  so it’s recommended for daytime use as it will not usually get in the way of your tasks. 

Grow Info


This is a great plant to grow as it’s easy for beginners. There is no particular equipment needed and minimal care is needed for the upkeep. The seeds are easy to find as they are available in many online stores. Being a strain derived from two legends has its perks. 

Flowering time 

This strain has a flowering period of 8 to 9 weeks. The genetics from its Critical Plus parent make it a fast-growing uniform plant with nicely developed branches. The Genetics from its Jack Herer parent makes it a tall plant with large stems.

This plant will bloom fast and will perform better in a sunny, dry Mediterranean climate, or a greenhouse. However, what makes this plant even cooler is that it can face the elements and it resist moisture.

When rain hits, this is when the buds will become voluminous and their trichomes will get ripe. 

Strain Yield

If it is the yield you’re after, this is the strain for you. This plant delivers a generous crop that you should keep in mind before committing. You’d be able to achieve crops of up to 623g/m2 indoors, and 1200 g outdoors!

Dave Roberts
Latest posts by Dave Roberts (see all)