Jack's Critical Strain Review: THC, Effects, Flowering Time & Yield

Jack's Critical is an original QCS strain: a feminized autoflower, (Jack Herer x Critical Mass) x Ruderalis, that QCS lists at 20% THC, with 60 to 70 days of flowering and up to 500 g/m² indoors. This Jack's Critical strain review covers our own specs and what growers generally report about both parents, so you can decide if it belongs in your tent.

Jack's Critical strain at a glance

What is the Jack's Critical strain?

Jack's Critical is an original QCS strain: Quebec Cannabis Seeds is its original breeder, and these are our own genetics, bred in Quebec since 2015 by a grower with more than 35 years of experience.

The Jack's Critical strain is a feminized autoflower bred by Quebec Cannabis Seeds from Jack Herer and Critical Mass, then crossed with Ruderalis so that it flowers on its own clock. The idea is to put a bright, zesty sativa-leaning parent together with a famously productive, heavy-yielding one, and wrap it in a plant that never needs a change of light hours.

Both parents are well known. Jack Herer is commonly described as a spicy, piney, uplifting sativa-dominant classic. Critical Mass is often described as a high-yielding, indica-leaning hybrid with a skunky, earthy, slightly sweet profile and a relaxing body feel. QCS says the plant combines a euphoric lift with the relaxation of the Critical side.

A quick note: many seed companies sell strains with similar names, and each uses its own breeding. Lineages, THC figures and flowering times you read elsewhere may describe a different cross. The numbers on this page are for the QCS version only.

Is Jack's Critical indica or sativa?

QCS lists Jack's Critical simply as an autoflower hybrid and does not publish an indica/sativa percentage, so we will not invent one. What we can say from the parents is that you get one leaning-sativa and one leaning-indica parent, and from the product page that the plant is compact and easy to keep under control.

Compact plants are a big plus for tents, closets and balconies. If you want to understand what the indica side of the family contributes, our guide to what indica does to you is a useful read.

Smell and flavour: citrus, skunk and diesel

QCS lists the taste as citrus, skunk, diesel and floral, and describes the aroma as citrus, pungent and skunky, with a strong diesel note on the inhale. That reads like a handsome meeting of the two parents: the bright, lemony Jack side over the gassy, skunky Critical base, with a floral edge.

Growers commonly report that skunky, diesel-type plants are loud in late flower, so plan for odour control if you grow indoors. A slow dry and a few weeks of curing will pull the citrus forward.

Jack's Critical effects

QCS describes the effect as a euphoric lift followed by relaxation, with the Critical Mass side bringing the calm and the CBD content softening the edges. That matches what consumers commonly report from Jack and Critical relatives: a happy, bright start that moves into a more settled, body-friendly feeling.

Effects vary from person to person and with the dose. Dry mouth and dry eyes are commonly reported downsides. QCS advises newer consumers to start with a small amount, and we agree.

How strong is Jack's Critical? THC and CBD content

QCS lists Jack's Critical at 20% THC. The product page also lists 8% CBD, which is unusually high for a strain from these parents; treat it as the figure QCS publishes for its own version, and ask us if the exact cannabinoid balance matters for you. THC and CBD both depend on how the plant is grown, dried and cured. For something much stronger, see our seeds over 25% THC.

Growing Jack's Critical: flowering time and yield

Indoors, expect 60 to 70 days of flowering (about 9 to 10 weeks) and a yield of up to 500 g/m². QCS does not publish an outdoor harvest date or outdoor yield for this one, only that you should sow after the last frost, so we will not guess. Because it is an autoflower, you can sow outdoors in spring or early summer and the plant will flower on its own schedule.

QCS rates it beginner-friendly: easy to grow and compact. The usual autoflower rules apply. Sow straight into the final pot, keep the medium damp but not soaked at around 22 to 25 degrees C while the seed sprouts, and keep conditions stable. Use the same light schedule from start to finish, avoid transplanting and heavy pruning, and water, feed and check the plant regularly, because an autoflower cannot recover lost time. Harvest by checking trichomes, not the calendar.

What customers report

Jack's Critical does not have any customer reviews on our site yet, so we will not invent any. The specs on this page come from QCS's own information, not from customer grows. If you grow it, tell us how it went, and a review helps the next grower.

Across the web, growers of Jack Herer and Critical Mass lines commonly report vigorous plants, heavy yields from the Critical side, a pungent odour and a fairly tall, stretchy frame from the Jack side. These are general reports about the parents, not promises for this autoflower.

Is Jack's Critical right for you?

Choose Jack's Critical if you want a compact, easy autoflower with a bright citrus-and-diesel profile, a 20% THC punch and no light schedule to manage. It suits beginners, small spaces and growers who like a quick turnaround. If you want a much stronger autoflower, read our review of Fat Bastard Autoflower.

See more in our autoflower seeds range or browse all marijuana seeds.

Jack's Critical: frequently asked questions

A note on the numbers in this article: harvest dates, flowering times and yields are ranges, not promises. They vary depending on growing conditions: the grower, the method and the season's weather. No strain is 100% mold resistant. How we set these numbers →

View Jack's Critical seeds →