Grow Light Coverage: Matching a Fixture to Your Tent Size
By The Budometry TeamPublished Updated
Manufacturers publish two footprints. The bigger one is for veg at lower intensity; the smaller one is what you can actually flower under.
Part of our pillar guide: Cannabis Grow Lights: Sizing, Height and Schedules
Read the flower footprint
A light advertised as covering 5x5 in veg often only supports flower-grade intensity across 4x4 or even 3x3. Always size to the flower number.
Edge falloff
Intensity drops sharply at the edges of a footprint. Plants in tent corners run 30-50% lower PPFD than center plants and finish with looser buds. Reflective tent walls recover some of that.
Fixing uneven coverage
Rotate pots a quarter turn every few days during veg, keep the canopy flat with training so no plant sits in a shadow, and consider two smaller fixtures instead of one central light in square tents.
Frequently asked questions
- Do reflective walls really help?
- Yes, meaningfully at the edges. Keep tent walls clean and avoid hanging equipment that blocks them.
The full guide on this topic
Cannabis Grow Lights: Sizing, Height and Schedules
How to size an LED to your tent, set hanging height by stage, run 18/6 and 12/12 on a timer, and hit the PPFD and DLI numbers that actually grow flower.