Jack FlashStrain, Effects, Genetics, Grow Guide & Where to Buy
Few cultivars carry the cult following Jack Flash has built across the US grow community , and the appeal is easy to explain. It is a balanced hybrid (60% indica / 40% sativa) testing at roughly 19% THC, with a flowering window of 60-70 days as an autoflower. What follows is a complete reference: terpene-led effects, genetic background, indoor and outdoor grow guidance, and the fastest way to get Jack Flash seeds shipped to your state.
Jack Flash Quick Stats
THC
19%
Indica
60%
Sativa
40%
Autoflower
Yes
Flowering
60-70 days
Difficulty
intermediate
Indoor Yield
up to 450 g/m2
Outdoor Yield
up to 600 g/plant
Plant Height
Short
Jack FlashEffects & Experience
Reported effects center on creative, energetic, relaxed. Jack Flash pulls toward a balanced state where neither head nor body dominates, a profile that holds up across phenotypes when the seeds are grown to their potential.
Growing Jack Flash
Growing Jack Flash fits cooler climates where photoperiod strains struggle to finish before frost, autoflower timing is calendar-driven, not daylight-driven. Jack Flash runs on an 18/6 light schedule from seed to harvest, autoflower genetics ignore photoperiod, so there is no flip and no light-cycle change. Indoor yields land around up to 450 g/m2 under quality LED, and outdoor plants given full sun and 5-7 gallon containers reliably produce up to 600 g/plant. Expected plant height is Short, with intermediate cultivation difficulty. Practical tips that move the needle: defoliate strategically on day 21 of flower; remove fan leaves blocking interior bud sites without stripping the plant; and top once at the 4th node to encourage 4-6 even main colas instead of one dominant cola. The most common challenge growers report is training timing, top at the 4th node, not earlier and not later, for the best canopy distribution.
Jack FlashLineage & Genetics
This cultivar is part of the Royal King Seeds curated catalog. Read the description as a general profile rather than a guarantee of your specific pack.
Where to Buy Jack Flash Seeds in the USA
Jack Flash seeds ship from Royal King Seeds from within the United States. Estimated delivery is approximately 5-7 business days; actual timing varies by destination and carrier.
Jack Flash FAQ
Is Jack Flash indica or sativa?+
Jack Flash is a balanced hybrid with a 60% indica / 40% sativa split. The effects lean toward physical relaxation and a calm, settled headspace.
How long does Jack Flash take to flower?+
Jack Flash flowers in 60-70 days from seed, since autoflower genetics ignore light cycle. Outdoor harvest typically lands 70-90 days after planting.
What is the THC content of Jack Flash?+
Jack Flash tests at approximately 19% THC when grown to its potential. Real-world numbers depend on grow conditions, harvest timing, and curing, well-grown phenotypes can land at the high end of that range, while poorly cured flower tests lower.
Is Jack Flash good for beginner growers?+
Jack Flash is rated intermediate difficulty. The autoflower genetics simplify the process, no light schedule changes and a fast seed-to-harvest timeline make it forgiving for first-time growers. Most growers with one harvest behind them handle this strain without difficulty.
Where can I buy Jack Flash seeds in the USA?+
Royal King Seeds ships Jack Flash seeds from within the United States, with estimated delivery in approximately 5-7 business days. The product page is at https://royalkingseeds.us/jack-flash-auto.