Grow Diary Granddaddy Purple

Granddaddy Purple - Transition into Early Flower

This week marked the full completion of Granddaddy Purple’s transition from late vegetative growth into true early flower. Transition lasted a total of 8 days, beginning immediately after the 12/12 flip and ending when pistils became consistently visible across the entire canopy. While the very first pistils appeared on day 30 post-emergence (6 days after flipping to 12/12), they were isolated to the top node or top two nodes. True flowering - defined as pistils emerging on all four branch sets - was confirmed on day 33, which now serves as Flower Day #1. Today is day 36 post-emergence, Flower Day #4, and the first full flower tufts are now forming.

The transition period was dominated by extreme vertical momentum. GDP1 stretched aggressively, but GDP2 was the standout, climbing 2 to 2.5 inches per day at times - even while being bent and tied. Both plants responded exceptionally well to daily low-stress training, widening their structure, opening airflow lanes, and preventing apical dominance from overtaking the canopy. A small amount of lower and mid-canopy defoliation helped remove crowded leaves without sacrificing upper growth, ensuring light penetration and humidity control as stretch peaked.

Nutritionally, the plants were held in a deliberately moderate range while still supporting their explosive growth. Feed strength averaged ~900 PPM using an early-bloom formula, with pH consistently adjusted to 6.0–6.1, the sweet spot for PRO-Mix HP’s peat-based chemistry. Cal-Mag at 5 mL/gal remained essential due to rapid cell expansion, while silica was applied every other feeding to reinforce stems during the heaviest stretch phase. Though runoff readings remained low in pH (5.0–5.3) and surprisingly high in PPM, neither plant showed toxicity or lockout symptoms - likely because their vigor and stretch rate were consuming nutrients at a high pace.

Light management was one of the most critical components of this week. As the canopy surged upward, the light was raised repeatedly until it reached near-maximum height, leaving only a few inches before contacting the filter. PPFD increased from the mid-600s into the 750–900+ range, with short periods where GDP2 briefly exceeded optimal intensity. To regain stretch control without compromising flower formation, the dimmer was adjusted to establish a consistent 850 PPFD ceiling at the highest cola, with the rest of the canopy ranging 650–800 PPFD. This places DLI comfortably between 34–37, a strong but safe target for early flower that encourages bud formation while reducing further vertical acceleration. UVA exposure was also increased from 30 minutes to 60 minutes with no adverse effects.

By the end of the week, both Granddaddy Purple plants entered early flower in excellent condition. Flower initiation is underway across every top, the structure is open and well-trained, and vertical growth - while still present - is beginning to show the first signs of slowing as hormonal priorities shift from elongation to cluster development. Despite a challenging stretch and tight vertical constraints, GDP1 and GDP2 remain healthy, balanced, and poised for a strong flowering run.

GDP1: 40.5"
GDP2: 42.5"