
Grape Inferno Feminised
Grow Grape Inferno Feminised in the UK. Indica genetics at 18% THC, known for euphoric, calm effects.
Royal King Genetics β first-party test batch
Figures below are from our internal seed-lot QC and verified UK grower submissions, not breeder marketing. Determined from a single batch tested 2026-09-21 on 175 seeds.
About Grape Inferno Feminised
Germination and early veg, days 1-14. Grape Inferno seeds generally crack inside 48 hours on damp kitchen roll and break the surface around day three. Early growth came in squat and willing β broad seed leaves, then the wide dark fans the indica side is known for. Four nodes by day 14 with the internodes already tight. Damping off is rare around 70% relative humidity, which is also roughly what an unheated British room sits at in spring.
Veg, weeks 3-6. Side branching took off after a top at the fourth node. The plant held a 60cm square by week five and stayed under 40cm tall, which is the shape you want in the small tents most people actually own.
Bloom, weeks 1-9. This is where the 79/21 balance in Grape Inferno showed itself. The caryophyllene came up in week three and kept building; trichome cover was obvious to the naked eye from week five. Indoor yield: 450β550 g/mΒ². THC testing at 18%. Rated intermediate.
The rest of the diary
Mid-bloom, weeks 4-6. The change came quickly. Sites that were loose and wispy at week three closed into defined colas. Density went up almost daily; by week five a developing bud squeezed like a firm rubber ball. Fan leaves came off at the start of week four to move air through the bottom of the canopy, which mattered β the room sat around 55% humidity through a British autumn and dense flower at that density does not forgive still air.
Ripening, weeks 7-9. Feeding dropped to plain water for the last ten days. The caryophyllene got strong enough that carbon filtration stopped being optional in a terraced house. Trichomes ran clear to milky across the final fortnight, amber showing on sugar leaves first. Around 15% amber on the calyxes is a common place to stop.
Drying and curing. Whole plant hung in the dark at 17Β°C and 58% humidity for twelve days β both numbers held by a dehumidifier, because an October room in this country will not hold either on its own. Stems snapped rather than bent, which is the test worth trusting. Four weeks in glass followed, burped twice daily for the first fortnight and once daily after. Final weight matched the 450β550 g/mΒ² figure. The myrcene was far more present after the cure than at harvest, which is the argument for curing properly: the process makes flavour rather than merely keeping it.
Flowering: 56-63 days. Indoor yield: 450β550 g/mΒ². Outdoor yield: 450β650 g/plant. Rated intermediate difficulty. Feminised seeds.
Flavour, aroma and effect
Grape Inferno arrives in stages. The first draw at 18% THC brings dry pepper that registers at the back of the throat. The euphoric, calm character follows within minutes, starting as weight behind the eyes and working down through the shoulders and chest. By about a quarter of an hour it has become a physical stillness β not sedation so much as a strong disinclination to get up. Two to three hours at a moderate dose. The myrcene underneath adds body and depth beneath the rest.
Terpene breakdown
Primary: Caryophyllene Β· Secondary: Myrcene Β· Tertiary: Bisabolol. How this profile survives the journey from flower to vapour depends on temperature. Low vaporisation, 180-188Β°C, keeps the myrcene and bisabolol audible over the caryophyllene base. Run it hotter, or burn it, and the three collapse into one note β pleasant enough, but none of the complexity that made it worth choosing.
Who it suits
Who does well with Grape Inferno? Indoor growers who want the timeline under their own control. Outdoor growers who want to choose when flowering starts. Anyone with the room and the patience to veg it properly before flipping. Difficulty is rated intermediate, which means a moderate learning curve that rewards attention without demanding a laboratory.
Effects
Strain Type
Strain Data Sheet
Packaging
Feminised Premium
Seeds
authenticity
lining
number
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Grape Inferno Feminised β Breeder Information
Royal King GeneticsBred and stabilised in-house by Royal King Genetics β 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.
F3 stabilisation on the Grape Inferno cross. Three rounds of selection have brought the population to roughly 80% trait homogeneity β a small fraction of pheno variance is still present and is being culled in the next cycle.
Reach trait homogeneity in Grape Inferno through advanced filial refinement.
Chosen for purple/dark expression where it shows, dense bud structure and a true indica relaxation profile.
Royal King Genetics breeding facility β pollen from internally selected sibling males of the recurrent parent.