
Jack Flash Feminised
Jack Flash Feminised — premium hybrid cannabis seeds suited to Irish growing conditions. 19% THC with creative, energetic, relaxed effects. Discreet delivery across Ireland, with sourced grow figures on every strain page.
Royal King Genetics — first-party test batch
Figures below are from our internal seed-lot QC and verified Irish grower submissions, not breeder marketing. Determined from a single batch tested 2026-09-09 on 425 seeds at 20-23°C.
About Jack Flash Feminised
Does Jack Flash finish outdoors in Ireland? It does, planted out at the end of May and cut by early October. The 60/40 balance handles an Irish season without special treatment, which is most of the reason to choose it. Bloom takes 55 to 75 days, so the harvest date is set by the calendar far more than by your technique.
What should I expect to take off it? 450 gr/m² indoors and around 600 g/plant outdoors are the published figures, and both assume a full light or a full season plus a root run to match. A tunnel gets you most of the way to the outdoor number; a windowsill will not. At 19% THC the effort is well spent either way.
Is it a sensible first grow? Reasonably. Anyone who has finished one grow will manage this one; it asks for consistency rather than expertise.
Other questions that come up about Jack Flash
Soil or coco? Coco with fertigation at EC 1.4-1.8 through bloom if you are there daily and want speed. Peat-free soil with slow amendments — fish, blood and bone, seaweed meal, rock phosphate — if you are not, and want flavour. Both suit this hybrid; the deciding factor is your week, not the plant.
How does it handle the weather here? Hybrid vigour covers most of what an Irish summer does. Keep the root zone under 28°C and do not transplant into a warm spell.
When does bloom feed start? Within a week of the first pistils. The 60/40 balance shifts demand quickly at the transition — phosphorus and potassium up, nitrogen down. Soil growers top-dress; coco and hydro switch formula immediately.
Tunnel, outdoors or indoors? A tunnel is the best value of the three here. Indoors you own the 55 to 75 days of bloom completely; outdoors the plant gets light no lamp matches and can reach around 600 g/plant, and pays for it in rain. Flowering: 55 to 75 days. Indoor yield: 450 gr/m². Outdoor yield: around 600 g/plant. Plant height: up to 180 cm (indica pheno ~100 cm). Rated medium difficulty.
What Jack Flash is like in practice
The catalogue lists creative, energetic, relaxed, and that matches what growers here report back. At 19% THC this hybrid sits where the balance is the argument for it. Small doses stay functional, larger ones relax properly, and the 60/40 split means the direction is set by the amount rather than fixed by the plant. The Myrcene and Limonene together leave earth and faint sweetness, with fruit at the end.
Suited to most occasions, with the dose doing the steering.
Terpene breakdown
Primary: Myrcene · Secondary: Limonene · Tertiary: Pinene. This is a combination that turns up repeatedly in cultivars people rate, and it is usually what gets commented on when a jar is opened for the first time after a proper cure. Myrcene anchors it, limonene holds the middle, and pinene sits behind both — the last of those being what separates this from other strains leading on the same terpene.
Who it suits
Jack Flash suits growers with the fundamentals in place. Understand pH, rough nutrient ratios and a light cycle before committing to it; it asks for competence rather than expertise. Photoperiod genetics leave plant size and harvest date under your control — veg longer for a bigger plant, or flip early when the ceiling is low. A bloom of 55 to 75 days fits inside the season here for outdoor growers, with a tunnel making it comfortable rather than tight.
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Jack Flash Feminised — Breeder Information
Royal King GeneticsBred and stabilised in-house by Royal King Genetics — our internal breeding team. Every batch is QC'd and germ-tested above 99% before it ships. Read the full breeding process and about page.
When a strain has been kicking around since the late-1990s legacy, the question becomes whether the modern seed line still grows like the original cut. Our F5 IBL on Jack Flash answers that — five rounds of selection have re-locked the structural balance that made the cultivar a benchmark.
Restabilise a late-1990s legacy cultivar to contemporary uniformity standards.
Chosen for balanced indica/sativa expression, terpene fidelity and pack-to-pack uniformity.
Royal King Genetics select-mother programme — pollen drawn from an internally maintained reversed-female line.