Granddaddy Purple Auto Seeds

Genetics & effects

Granddaddy Purple Auto is a feminised autoflower combining Granddaddy Purple with ruderalis genetics. Its profile is approximately 80% indica and 20% sativa, with catalogue figures of 15–22% THC and 0–1% CBD. As an autoflower, it moves into bloom according to age rather than a change in daylight hours, making it an approachable option for growers who value a compact plant and straightforward scheduling.

The flavour and aroma profile leans towards sweet berry, ripe cherry and mixed fruit, layered with pepper, pine and light floral notes. Myrcene, caryophyllene, pinene and linalool shape this rounded, dessert-like character. Experiences vary, but consumers commonly describe the effects as relaxed, calming and gently euphoric. Some may perceive an uplifting opening that gradually becomes heavier or sleepier, particularly later in the experience.

Explore autoflower seeds, high thc seeds, the Australian grow guide, and the planting calendar.

Explore autoflower seeds, high thc seeds, the Australian grow guide, and the planting calendar.

Growing in Australia

This variety is listed as beginner-friendly and suited to hot, dry, temperate, and cool regions with shorter seasons. Its compact 50–100 cm stature can fit smaller gardens, balconies or controlled indoor spaces. Autoflowering plants generally favour a smooth start, as their fixed development schedule provides limited time to rebound from major stress.

Use a light, free-draining medium and avoid overwatering young plants. Stable conditions, gentle airflow and careful observation can reduce the risk of mould or slowed growth. In Australia, outdoor spring planting generally falls between September and November. Local temperature, rainfall and daylight conditions should guide the exact timing.

Indoor

Indoors, Granddaddy Purple Auto usually remains between 50 and 100 cm. The flowering stage is listed at approximately 8–9 weeks, although the complete seed-to-harvest cycle may be longer. A consistent light schedule and moderate feeding approach suit its compact autoflower structure.

• Indicative indoor yield: up to 300 g/m²
• Indoor height: approximately 50–100 cm
• Difficulty: beginner-friendly

Good air exchange is especially useful as flowers gain density. Allow space between plants, manage humidity and inspect shaded growth regularly. Cooler finishing temperatures may encourage deeper purple colour, though expression depends on both genetics and growing conditions.

Outdoor

Outdoor plants are also expected to reach around 50–100 cm, making this variety relatively discreet in size. Choose a sunny position with drainage and shelter from prolonged rain or strong wind. In hotter, drier areas, mulch can help moderate moisture swings, while growers in cool or short-season regions may prefer the warmest available position.

• Indicative outdoor yield: up to 80 g per plant
• Outdoor height: approximately 50–100 cm
• Preferred conditions: sun, airflow and free-draining soil

Harvest

For seasonal outdoor cultivation in Australia, the main harvest period is generally March to May. Autoflower timing can place individual plants earlier depending on sowing date and local conditions, so plant maturity is the better guide. Look for swollen flowers, changing pistil colour and developed resin glands rather than relying on the calendar alone. Yield, potency, colour and finish remain variable. Outback Seed Bank presents these figures as catalogue guidance rather than fixed outcomes.