Plant lighting per square metre: area, coverage and measurement

The number of LEDs per square metre is not enough to size plant lighting. Distance, optics, distribution and foliage affect the light received.

Distinguish room area from foliage area

A decorative lumen calculation for a living room is not automatically a horticultural method. Measure the area actually covered by the plants and the available mounting height. Lumens and lux cannot be converted to PPFD using a universal factor independent of spectrum.

Compare documented coverage

If a manufacturer publishes a measurement map, record the distance, area, model and setting. A reading at the centre does not describe every edge. Without this information, request documentation instead of promising a lamp count that will suit every pot.

Choose for your setup

Read the use-based comparison and then browse indoor plant lights. The distance guide adds to this method; the energy-use calculator covers a different subject: electricity cost.

Editorial review: 3 October 2026 · TerraLED. Set up your equipment according to its instructions and the needs of the species.