Jack F1 by Spliff Seeds
A sativa-leaning cross of Jock Horror, Jack F1 — released by Spliff Seeds — 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. The environment targets below are the same stage-by-stage bands the Cultivar journal grades real Jack F1 grows against.
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Similar strains
| Breeder | Spliff Seeds |
|---|---|
| Type | mostly sativa |
| Flowering time | ±67 days |
| Environment | Outdoors |
| Lineage | Jock Horror |
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Ancestry Pedigree
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Growing Jack F1: 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 Jock Horror 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.
Jack F1 FAQ
How long does Jack F1 take to flower?
Jack F1 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 Jack F1 an indica or a sativa?
Jack F1 is listed as mostly sativa.
What are the parents of Jack F1?
Jack F1 was bred from Jock Horror by Spliff Seeds.
What environment does Jack F1 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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Facts compiled from public breeder listings. Growing Jack F1? A structured journal — with your feedings, readings, and photos — is how you find what THIS cut actually wants.
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