C4 Strain — Effects, Genetics, Grow Guide & Where to Buy
C4 is one of the most-searched cannabis strains in the United States, with a profile that holds up under scrutiny. It is a balanced hybrid (50% indica / 50% sativa) testing at roughly 20% THC, with a flowering window of 8-10 weeks under a 12/12 photoperiod. This guide pulls together the lineage, the effects, the grow data, and the practical answer to "where can I buy C4 seeds in the USA" in one place.
C4 Quick Stats
THC
20%
Indica
50%
Sativa
50%
Autoflower
No
Flowering
8-10 weeks
Difficulty
intermediate
Indoor Yield
450-550 g/m²
Outdoor Yield
500-700 g/plant
Plant Height
120-180 cm
C4 Effects & Experience
Reported effects center on euphoric, focused, happy. C4 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 C4
Growing C4 fits outdoor growers with at least 130 frost-free days; the balanced structure handles both heat and cool nights. C4 is photoperiod, which means you control when it flowers by switching from 18/6 (vegetative) to 12/12 (flowering). Most indoor growers veg for 4-6 weeks before the flip. Indoor yields land around 450-550 g/m² under quality LED, and outdoor plants given full sun and 5-7 gallon containers reliably produce 500-700 g/plant. Expected plant height is 120-180 cm, with intermediate cultivation difficulty. Practical tips that move the needle: apply low-stress training in week 2 of veg — bend the main stem horizontally and tie down to expose lower nodes; and flush nutrients in the final 10-14 days for cleaner flavor; trichomes finish properly even on plain pH-adjusted water. The most common challenge growers report is over-feeding nitrogen past week 1 of flower — switch to bloom nutrients within 7 days of seeing pistils.
C4 Lineage & Genetics
C4 is a Royal King Genetics in-house cross. The parental selection was chosen for hybrid vigor and a balanced effect profile, then stabilized over multiple generations to lock in phenotype expression. Seeds run true to the description on this page rather than spreading across a wide range of expressions.
Where to Buy C4 Seeds in the USA
C4 seeds ship from Royal King Seeds to all 50 US states with discreet packaging and a 95% germination guarantee. Average delivery is 3-5 business days, with the fastest routes typically reaching Alaska, Arizona, Arkansas, California, Colorado.
C4 FAQ
Is C4 indica or sativa?+
C4 is a balanced hybrid with a 50% indica / 50% sativa split. The effects lean balanced — neither dominantly head nor body.
How long does C4 take to flower?+
C4 flowers in 8-10 weeks once you flip to 12/12 light cycle. Outdoor harvest typically lands in late September to mid-October across most US zones.
What is the THC content of C4?+
C4 tests at approximately 20% 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 C4 good for beginner growers?+
C4 is rated intermediate difficulty. Photoperiod genetics give you control over plant size and harvest timing, which means a bit more responsibility for getting the schedule right. Most growers with one harvest behind them handle this strain without difficulty.
Where can I buy C4 seeds in the USA?+
Royal King Seeds ships C4 seeds to all 50 US states with discreet packaging, 3-5 day delivery, and a 95% germination guarantee. The product page is at https://royalkingseeds.us/c4-feminized — checkout accepts standard cards, Apple Pay, and crypto.