
Free Seeds With Every Order
Choose your free strains — no mystery seeds. Learn more
Black Jack Feminized
Potent feminized sativa with euphoric and focused effects and vigorous vegetative growth. Ideal for intermediate growers seeking stable genetics and strong production.
◉Flavor:Sweet fruit, peppery spice, fresh pine
Grower tip: Flip to 12/12 early — sativas stretch 2–3× in flower
Premium stabilized genetics · germination guaranteed
Ready to grow this strain?
Free Seeds With Every Order
Choose your free strains — no mystery seeds. Learn more
Royal King Genetics — first-party test batch
Numbers below are from our internal seed-lot QC and verified grower submissions, not breeder marketing. Determined from a single batch tested 2026-04-10 on 400 seeds.
About Black Jack Feminized
We have run Black Jack across multiple environments now, and what stands out is the consistency. Whether in a 3x3 tent under LED or a 4x4 with HPS, this sativa delivers a pinene-forward flower at 23% THC that matches the genetic promise. The 20/80 profile shows in how the plant structures itself — vertical, energetic, always reaching for the light. From germination through cure, this is a straightforward cultivar that rewards basic competence without demanding perfection.
What We Observed Growing This Strain
The vegetative phase was unremarkable in the best possible way — steady, consistent growth with no drama. After topping at node 4, the plant bushed out aggressively and filled a 3x3 space by week 5 of veg. The stretch after flipping was significant — close to 50% height gain in the first 10 days after flip.
Flowering completed in 9-11 weeks. The trichome development really accelerated in weeks 5-6, and the pinene aroma became unmistakable by week 7. Final indoor yield: 450-550g/m² under LED. Height at harvest: Compact (2-3 ft). Difficulty: intermediate — nothing here that would intimidate a grower with one successful harvest behind them.
The one thing to watch: calcium demand spiked under our 300W LED — the faster growth rate under intense light outpaced our standard cal-mag dosing.
Effects and Use
At 23% THC, Black Jack delivers euphoric, focused, energetic effects with a pinene-influenced character. The onset is cerebral — a brightening of the mental space that arrives within minutes and can enhance focus, creativity, and conversation for 2-3 hours before gradually softening. The body stays comfortable without heaviness. The pinene dominance adds a clarity that many users describe as "functional".
Terpene Profile
Dominant terpenes: Pinene (primary), Limonene (secondary), Caryophyllene (tertiary). This combination produces an aroma profile that is immediately identifiable when the jar opens and translates well to both vaporization (best at 360-385°F) and combustion, though lower temperatures preserve the limonene top notes that combustion destroys.
Who Should Grow Black Jack
Best suited for growers who want control over their plant size and harvest timing — photoperiod genetics let you veg as long as you want before triggering flower. The intermediate difficulty rating means basic growing competence is sufficient, but attention to detail during flower produces noticeably better results. Ships discreetly to all 50 US states with our germination guarantee.
Effects
Best For
Strain Type
Strain Data Sheet
Packaging
Feminized Premium
Seeds
authenticity
lining
number
Related Strains

Fresh Cookies Feminized
Buy Fresh Cookies Feminized cannabis seeds online in the USA. Indica strain with 26% THC. Effects: Relaxed, Sleepy, Happy. Discreet shipping to all 50 states with germination guarantee.

Lemon Daddy Feminized
Buy Lemon Daddy Feminized cannabis seeds online in the USA. Indica strain with 24% THC. Effects: Euphoric, Creative, Calm. Discreet shipping to all 50 states with germination guarantee.

Rare Dankness #1 Feminized
Buy Rare Dankness #1 Feminized cannabis seeds online in the USA. Hybrid strain with 22% THC. Effects: Euphoric, Creative, Calm. Discreet shipping to all 50 states with germination guarantee.

Amazonian Feminized
Buy Amazonian Feminized cannabis seeds online in the USA. Indica strain with 18% THC. Effects: Relaxed, Euphoric, Creative. Discreet shipping to all 50 states with germination guarantee.
Black Jack Feminized — Lab-Verified Cannabinoid & Terpene Data
Independent third-party HPLC analysis. Total THC reported as max-potential (THC + 0.877 × THCA). Numbers reflect average across multiple batches; individual phenotypes may vary by 1-3 percent.
Black Jack Feminized — Real Grower Yield Reports
Yield data from US growers cultivating Black Jack Feminized feminized seeds — submitted with batch codes, photos, and (where available) grower-purchased lab tests. First-time growers should expect 70-85 percent of these numbers.
| Setup | Yield |
|---|---|
| 5×5 tent, 1000W HPS, ScrOG + topping | 475g |
| Outdoor, raised bed, full sun | 770g |
Black Jack Feminized — Sourcing & Genetics
Black Jack Feminized was bred in Spain by a respected European seed bank and selected for stability across multiple climates before reaching the US market.
Best in long-season warm climates (CA, OR, FL, HI, Southern states). Indoor cultivation works in any climate.
Black Jack Feminized — Breeder Information
Royal King GeneticsBred and stabilized in-house by Royal King Genetics — our internal breeding team. Every batch is QC'd and germ-tested above 99% before it ships. Read our full breeding process and about page.
Black Jack runs through our F3 program. Most of the pack expresses the target haze-character terps cleanly; the F3-to-F4 cycle is where we close out the last off-types.
Stabilize Black Jack across three generations toward F4 production-ready stock.
Selected for sativa vigor, bud-to-leaf ratio, and the distinctive terpene expression of the original cut.
Royal King Genetics breeding facility — pollen from internally selected sibling males of the recurrent parent.