Grow Diary Granddaddy Purple

Granddaddy Purple - Week #2 of Flower (Early Flower)

Granddaddy Purple continues to develop beautifully, though with a different growth trajectory from God’s Gift. Whereas God’s Gift closed its stretch early in the week, Granddaddy Purple continued to grow slowly throughout the entire period. Both GDP plants reached 51 inches by Day 47, with daily gains of roughly 0.25–0.50 inches still occurring. Stretch factors sit at roughly 3.0x for GDP #1 and 2.76x for GDP #2, meaning the cultivar has not fully completed its elongation phase yet. This is consistent with GDP’s tendency to stretch longer into early flower despite being an indica-dominant strain. The logistic curve fits confirm that GDP is close to leveling off, but small increments of vertical growth remain possible for a few more days.

The surge in height earlier in the week made it necessary to install a structural grid to maintain canopy control. Once installed, the grid allowed each spear to be pulled outward and horizontally tensioned so that the upper canopy remained flat, even, and fully exposed to high PPFD. Beneath the screen, I performed a full defoliation, removing all lower nodes and branches receiving less than ~250 PPFD. This cleanup dramatically improved airflow and eliminated non-productive sites. Above the screen, I continued strategic leaf removal - mainly inward-facing fans and small leaves wrapping around budlets - to keep light penetration consistent along the entire 25-inch cola length typical for these plants.

I fed Early Bloom nutrients every other day at Medium strength (~900–910 ppm). Silica (0–1.5 mL/gal) and Cal-Mag (5 mL/gal) were included, and pH was maintained at 6.0–6.1 to optimize cation uptake in Pro-Mix HP. The plants have responded extremely well - no burn, no deficiency, and no signs of nutrient stress despite the intense metabolic demands of active stretch. PPFD levels across the tops range from 935–945 (40-41 DLI), which is strong for this stage of development. To accommodate GDP’s height, I had to relocate the exhaust system from the upper tent framing to a vertical side position so that the light could be raised fully to the ceiling, ensuring the critical 10–12 inch buffer from the canopy.

Aromatically, GDP is now becoming loud with hints of grape and citrus. Trichomes are beginning to appear across the sugar leaves in increasing density, signaling the start of resin production. My cooler nighttime temperatures (low–mid 60s), stable VPD, and high but non-stressful PPFD are all deliberate choices to enhance terpene synthesis and preserve volatile compounds.

By the end of the week, GDP stands tall and powerful, with large, well-spaced spears rising above the SCROG grid. The plants are vigorous, aromatic, highly responsive to training, and clearly transitioning into the true flowering stage. Stretch is nearly complete, but not quite finished, and flower expansion is accelerating across all tops.