Purple Arrow Auto

The way to plan Purple Arrow is backwards from the day you intend to cut, with up to 300 g/m2 per square metre indoors and up to 300 g/plant per plant outdoors as the figures you are working toward, at 21% THC. Count 50-60 days back from that date and you have your flip date. Most of the final weight lands between weeks 5 and 8, when calyxes stack fastest and trichome cover goes from patchy to complete. Outdoors in the Southern Hemisphere you want that fattening phase falling in February while the days are still long, which puts a late-March cut about right for most of the country.

Yield on Purple Arrow — the up to 300 g/m2 indoors and up to 300 g/plant outdoors quoted above — is decided in three short stretches of the 50-60 days bloom rather than evenly across it.

The first ten days after the flip. Whatever stretch happens here sets your canopy, and an uneven canopy wastes light for the remainder of the grow. Stretch is modest at 20-30%. Strip the lower fan leaves around day seven and that energy goes into bud sites instead.

Weeks three to five. This is when myrcene production climbs, and it answers to the gap between day and night temperature rather than to either number on its own. Keep at least 6-8°C between them. Outdoor growers in the interior provinces get that swing free in March and April; indoors, aim for 25-26°C lights-on against 18-20°C lights-off, with potassium-led bloom feed at EC 1.6-1.8.

The last ten to fourteen days. Stop feeding, flush with pH-corrected water, and read trichomes daily under a 60x loupe. Cut at 15-20% amber for the heavy end of what this genetics does. Outdoors that usually lands between late March and mid-April.

Difficulty: easy. In flower for 50-60 days. Stands 70–110 cm. Indoors it returns up to 300 g/m2. Outdoors, up to 300 g/plant a plant.

The effects most commonly reported for this cultivar are creative, calm. At 21% THC it sits in a bracket where the dose does most of the work. A single bowl vaporised at 185°C gives a manageable body relaxation with your head still intact — enough to close out a long day in the summer heat. Push the dose and it moves decisively toward physical sedation, which is how it tends to end up as a winter evening cultivar. The Myrcene/Humulene pairing leaves an earthy sweetness with a fruit finish on the palate.

Where it fits: quiet evenings, a film, recovery after exercise, and the hours before sleep.

Leading with Myrcene, then Humulene, and Linalool underneath. How this combination survives the move from flower to vapour or smoke is not a given. Held low, at 180-188°C, the humulene and linalool notes stay legible with myrcene underneath them. Run it hotter, or burn it, and the three collapse into one — still pleasant, but without the separation that makes this cultivar worth paying attention to.

Purple Arrow is a reasonable fit for growers with the basics already in place. Understand pH, know roughly what nutrient ratios do, and be able to hold a light cycle — it will not carry you, but it does not punish the occasional slip either. Because it autoflowers there is no light cycle to manage at all, which is what makes it work on a balcony, in an out-of-the-way outdoor spot, or anywhere a timer would be one more thing to go wrong. A September-to-May outdoor season comfortably covers a 50-60 days bloom in the frost-free provinces. Posted discreetly anywhere in South Africa, with sourced grow figures shown on every strain page.