Colombian Jack

Colombian Jack Feminised Cannabis Seeds by Kannabia

Colombian Jack is a sativa-dominant feminised cannabis seed from Kannabia that channels decades of legendary genetics into one citrus-drenched, resin-heavy plant. A cross between Black Jack and Nébula, this strain carries world-class sinsemilla lineage on both sides of the family tree. With 29% THC and yields up to 600g per plant outdoors, it delivers the kind of numbers that make experienced growers sit up and pay attention.

Genetics: Black Jack Meets Nébula

Colombian Jack's genetic profile reads like a greatest-hits compilation of sativa breeding. The Black Jack parent — itself a cross of Black Domina and Jack Herer — contributes structural integrity and resin production. Nébula, a sativa-leaning hybrid with Colombian and Haze ancestry, injects that soaring cerebral character and complex terpene profile. Every strain in this lineage, traced all the way back, would produce world-class sinsemilla. That's not marketing fluff — it's just what happens when breeders spend decades refining genetics instead of chasing trends.

The indica genes peppered through the heritage aren't dominant, but they do useful work. They keep the plant from stretching into unmanageable territory and help the colas fatten up during the final weeks of flowering. You get sativa effects in a frame that doesn't require a cathedral ceiling to grow.

Flavour and Aroma Profile

Crack open a cured jar of Colombian Jack and the first thing that hits you is lime — bright, sharp, almost aggressive citrus that fills the room. Underneath that top note sits a broader citrus salad character, layered with resinous incense and a savoury umami base that grounds the whole profile. It's complex enough to keep you sniffing the jar like a weirdo, which — honestly — is half the fun of growing your own.

The terpene complexity here points directly to the quality sativa genetics. Cheap sativa crosses give you one-note lemon and call it a day. Colombian Jack gives you a full conversation between sweet, sour, herbal, and earthy. If you're the type who picks strains by nose as much as by numbers, this one won't disappoint.

Growing Colombian Jack: Flowering Time and Yield

Colombian Jack finishes its flowering cycle in 64 to 71 days indoors, which is remarkably quick for a sativa-dominant strain pushing 29% THC. Most sativa-leaning genetics with this kind of potency want 10 to 12 weeks — Kannabia has trimmed that down without sacrificing quality.

Outdoors, plants reach around 200cm and deliver up to 600g per plant with harvest falling at the end of October. That height is manageable — you won't need to explain a 3-metre tree to your neighbours. Indoors, expect 500g/m² from plants that respond well to topping and training techniques. The extensive colas characteristic of sativa growth get nicely fattened by those background indica genes, so you're not left with wispy, airy buds.

One thing to watch: well before the fat yellow hairs begin to wither, buds are already substantial and trichome development is impressive enough to make extract makers start planning their next run. If you're into concentrates, Colombian Jack is a strong candidate for a dual-purpose grow — smoke some, press some.

Growing Environment and Tips

Colombian Jack performs well in both indoor and outdoor setups, but the sativa structure means you'll want to think about vertical space management indoors. Topping early and using a SCROG net will keep the canopy even and maximise light penetration to those lower bud sites. The 64-71 day flowering window gives you a reasonable turnaround for successive indoor runs.

Outdoors in northern European climates, the end-of-October harvest window is tight. You'll want a stretch of dry weather in late October to avoid mould issues on those dense colas. Mediterranean and southern European growers will have an easier time of it. If you're growing in the UK or the Netherlands, keep an eye on the forecast and have a plan for bringing plants under cover if the autumn rains arrive early.

The honest limitation here: 29% THC sativa genetics can be sensitive to nutrient burn. Colombian Jack isn't a heavy feeder in the way some indica-dominant strains are. Start at 75% of your usual nutrient schedule and work up. Overfeeding shows up fast as tip burn on those long sativa leaves, and it's easier to add than to flush and recover.

Colombian Jack vs Other Sativa Seeds

If you're comparing Colombian Jack to other sativa-dominant seeds in the Kannabia catalogue, the standout differences are potency and speed. Most sativa strains with comparable THC levels take considerably longer to finish flowering. The 64-71 day window puts Colombian Jack in the same turnaround territory as many indica-dominant hybrids, which is a genuine advantage if you're running a perpetual indoor setup.

Compared to a pure Jack Herer cut, Colombian Jack adds that Nébula influence — more citrus complexity, a deeper terpene profile, and the Colombian genetics that give the high its uplifting, creative character. If you've grown Jack Herer before and loved the effects but wanted more flavour depth and faster finishing, Colombian Jack is the logical next step.

Why Colombian Jack Deserves a Spot in Your Garden

We've been stocking seeds since the early days, and the strains that stick around in the catalogue year after year share a few traits: they deliver on the numbers, they taste good enough to grow twice, and they don't punish you for small mistakes. Colombian Jack ticks all three boxes.

The 29% THC figure isn't a lab cherry-pick from one exceptional pheno — it reflects the genetic ceiling that Kannabia has bred into this cross. The Black Jack and Nébula parentage means you're working with stable, well-established genetics rather than untested hype. Every seed in the 5-pack carries feminised genetics, so you're not wasting time, space, or nutrients on plants you'll cull at pre-flower.

The lime-citrus-incense terpene profile is genuinely distinctive. A lot of sativa seeds promise "complex flavour" and deliver generic lemon haze. Colombian Jack's umami base notes set it apart — there's a savoury depth that makes the smoke interesting rather than just pleasant. If you're the sort of grower who keeps a terpene journal (and if you're not, maybe start), this one will give you plenty to write about.

How to Grow Colombian Jack

1. Germinate seeds using the paper towel method or directly in a starter plug. Keep temperatures between 22-26°C and maintain high humidity (70-80%) during the seedling phase.
2. Transplant into your final container once the first set of true leaves has developed. A 15-20 litre pot works well for indoor grows; outdoors, go larger or plant directly into prepared soil.
3. Top plants once they've developed 5-6 nodes to encourage lateral branching and manage the sativa stretch. A SCROG net set at canopy height helps distribute light evenly across all bud sites.
4. Switch to a 12/12 light cycle to trigger flowering. Expect the stretch to add 50-100% height in the first two weeks of flower — account for this when positioning your lights.
5. Feed conservatively. Start at 75% of your nutrient manufacturer's recommended dose and increase only if the plant shows signs of hunger. Colombian Jack's sativa genetics are sensitive to overfeeding.
6. Monitor trichome development with a jeweller's loupe from day 55 onwards. Harvest when trichomes show mostly cloudy heads with minimal amber for the most uplifting effect profile. The 64-71 day flowering window gives you a clear target.
7. Dry in a dark, well-ventilated space at 18-21°C and 55-60% humidity for 10-14 days, then cure in sealed glass jars for a minimum of two weeks. The citrus and incense terpenes develop noticeably during a proper cure.

Frequently Asked Questions

Last updated: April 2026