Episode 12: Day 21 Flower Update, EarthBox Defoliation, Trellis Installation & PPFD Optimization

In this episode of the BuildASoil 10×10 Series, Season 9 Episode 12, I walk through one of the most important milestones of the flowering cycle as the garden reaches Day 21 of flower.

I begin with a full Week 12 update, comparing the different genetics in the room and showing how the fast-flowering varieties have stacked up compared to the slower-growing Lotus Larry replacement. I also discuss what I’ve learned from delaying the trellis installation and why timing becomes increasingly important as plants transition deeper into flower.

Next, I take a closer look at flower development, early terpene production, and canopy structure while evaluating each plant’s progress. The differences between genetics are becoming much more obvious, and I share my thoughts on stretch, stacking, and selecting potential keeper phenotypes.

From there, I perform a major Day 21 defoliation on the EarthBoxes, explaining why removing lower growth helps redirect energy toward higher-quality flowers. Along the way, I discover an unusual fasciated branch on one of the plants and discuss what may have caused the mutation.

I also inspect the living soil beneath the mulch layer, check root development, evaluate EarthBox limitations as the plants continue bulking up, and explain how I determine whether additional nutrition will be needed later in flower.

Finally, I install the trellis net, dial in plant support, adjust the Mammoth Lighting fixture using PPFD measurements, and make final light intensity changes to optimize flower development while maintaining quality through the remainder of the cycle.

By the end of this episode, you’ll better understand Day 21 flower maintenance, strategic defoliation, trellis timing, EarthBox management, PPFD adjustments, and how I prepare a living soil garden for the heavy flowering weeks ahead.

Disclaimer:
This content is for educational and informational purposes only. BuildASoil is dedicated to teaching the art and science of soil-based growing. Always follow your local laws and regulations.

TIMESTAMPS
00:00 – Intro
00:18 – Week 12 Update
09:37 – Flower Development & Early Terpene Check
13:06 – Defoliation Begins, EarthBox Limits & Fasciation Discovery
17:59 – Post-Defoliation Results, Trellis Prep & PPFD Planning
20:27 – Living Soil Check & PPFD Adjustments
22:15 – Trellis Net Installation, Light Tuning & Final Flower Setup
29:27 – Final Thoughts

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Music: Rebel by LionRiddims