Double Jack by Canadian Seed Lab
A sativa-leaning cross of Jack Herer, Double Jack — released by Canadian Seed Lab — shows up in a lot of tents for good reason. Indoors it typically finishes flowering in around 67 days after the flip to 12/12. Reported THC is 20% with CBD at 0.81%. The environment targets below are the same stage-by-stage bands the Cultivar journal grades real Double Jack grows against.
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Similar strains
| Breeder | Canadian Seed Lab |
|---|---|
| Type | mostly sativa |
| Flowering time | ±67 days |
| THC | 20% |
| CBD | 0.81% |
| Environment | Outdoors |
| Lineage | Jack Herer |
| Descendants | Double Jack Auto |
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Growing Double Jack: what to expect
As a sativa-leaning plant, plan for a big stretch after the flip (often 100–200%) — flip earlier than feels natural and keep training options ready. Sativa-leaning plants also generally prefer a lighter feed than heavy indicas. Growers familiar with Jack Herer will recognize much of its behavior. Whatever the listing says, the cut in YOUR tent is the ground truth: log feedings, readings, and photos, and let the trends — not the label — drive decisions.
Double Jack FAQ
How long does Double Jack take to flower?
Double Jack typically flowers in around 67 days after switching to a 12/12 light schedule. Individual phenotypes vary, so judge harvest readiness by trichome color, not the calendar.
Is Double Jack an indica or a sativa?
Double Jack is listed as mostly sativa.
What are the parents of Double Jack?
Double Jack was bred from Jack Herer by Canadian Seed Lab.
How strong is Double Jack?
Reported THC for Double Jack is 20% and CBD 0.81%. Actual potency depends heavily on environment, harvest ripeness, and cure quality.
What environment does Double Jack like?
Standard cannabis bands work well: VPD 0.8–1.1 kPa in veg and 1.0–1.4 kPa in flower, with humidity stepping down from 65–75% as a seedling to 40–50% in late flower. See the stage-by-stage table on this page.
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