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The Official Cannabis collection · sheet 10No 10 · Critical Jackvs Durban Poison

Comparison

Critical Jack vs Durban Poison

Leafly users report exactly the same top effects for both, focused, energetic and uplifted, from very different plants: Durban Poison is a pure sativa landrace from the South African port of Durban, in the US since the 1970s, while Critical Jack is a Spanish seed-bank hybrid on sale by 2015.1,2,3 Durban Poison tests higher in state labs: 19.45% median THC across 528 tests, against 15.01% for Critical Jack from only eight tests, a small sample.4

Side by side

Critical JackDurban Poison
TypeSativa-leaning hybrid; Dinafem lists 60% sativa / 40% indica2,3Pure sativa landrace1
OriginSan Sebastián, Spain (Dinafem Seeds)5,6Durban, South Africa; in the US since the 1970s1
Median THC (state lab tests)15.01% (only eight tests, a small sample)19.45% (528 tests)
Middle half of THC results13.41%–20.68%17.33%–21.99%
Top terpenes (median)Too few tests for a profile (1 of 8 with terpene values)Terpinolene, β-Myrcene, β-Caryophyllene (235 tests)
Leafly top effectsFocused, energetic, uplifted2Focused, energetic, uplifted1
FlavorPine, citrus, lemon2Pine, earthy, sage1
Flowering60 days indoors (Dinafem’s spec)37–9 weeks1

Lab rows come from the same state lab dataset and matching rules for both strains.4

Lab-tested THC: Critical Jack vs Durban Poison

12% 14% 16% 18% 20% 22% Durban Poison Durban Poison: median 19.45%, middle half 17.33%–21.99%, 528 tests 19.4% n=528 Critical Jack Critical Jack: median 15.01%, middle half 13.41%–20.68%, 8 tests 15.0% n=8 Median total THC (dot) and middle half of tests (bar)
Median and middle half of total THC in state lab tests. Small sample: Critical Jack has only 8 tests.4

Landrace against seed-bank hybrid

Durban Poison carries the name of the place it developed and was brought to the US in the 1970s; Critical Jack carries a company’s branding, and the company that bred it stopped selling seeds in 2020.1,3,7 Leafly notes Durban Poison fell from #6 to #19 in its 2025 order rankings, where Critical Jack does not appear at all.8

More comparisons

Sources

  1. Leafly, Durban Poison strain information. Accessed Oct 3, 2026.
  2. Leafly, Critical Jack aka Critical Jack Herer strain information. Accessed Oct 3, 2026.
  3. Dinafem Seeds, Critical Jack: feminized seeds, specifications, lab analysis and awards. Accessed Oct 3, 2026.
  4. Cannlytics (CC BY 4.0), cannabis_results: public state lab results (filtered and aggregated by Official Cannabis). Accessed Oct 3, 2026.
  5. Dinafem Seeds, Dinafem Seeds (home page: company address and seed-sales notice). Accessed Oct 3, 2026.
  6. Weedmaps, Critical Jack strain page. Accessed Oct 3, 2026.
  7. Público, La intervención judicial de uno de los mayores bancos de semillas de cannabis causa perplejidad en el sector (Santiago F. Reviejo) (2020-10-12). Accessed Oct 3, 2026.
  8. Leafly, The best-selling weed strains of 2025 (2026-02-02). Accessed Oct 3, 2026.