Grow Journal Post by GrowJournal | Grow Journal
A lot of growers are burning watts instead of building biomass. I see rooms pinned at 100% intensity from lights on to lights off, assuming max PPFD automatically equals max yield. It doesn’t. Photosynthesis has a speed ...
A lot of growers are burning watts instead of building biomass. I see rooms pinned at 100% intensity from lights on to lights off, assuming max PPFD automatically equals max yield. It doesn’t. Photosynthesis has a speed limit, and once you pass it, you’re just adding heat, stress, and HVAC load. In non–CO₂-enriched rooms especially, pushing 1200+ PPFD all day often hits diminishing returns by mid-cycle. The plants stop being light-limited and start being carbon- or heat-limited. You’ll see it as midday slowdown, harder transpiration demand, and leaves that look “on edge” instead of hungry. What’s worked better for me is mimicking nature’s cloud cover. I run a strategic ~20% light drop for about 90 minutes around peak midday. That short break: • Gives the photosynthetic machinery time to recover • Reduces leaf temp and VPD spikes • Cuts HVAC strain during the hottest window • And often results in better leaf posture by lights out Total DLI stays on target, but stress stays lower. Net result: happier plants and no loss in yield—often the opposite. More isn’t always better. Better is better.
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