Guide
Grow Lights for Houseplants: Distance, Hours and a Simple Setup
By the Plantshop.com Editorial Team · Updated · How we research · Report an error
If your plants lean, stretch or stall in winter, a grow light fixes the light deficit more reliably than moving pots around a dim room. This page is the practical setup guide; for bulb vs bar vs panel shopping, see our grow lights buying guide.
Usable intensity (without a lab meter)
University of Minnesota Extension recommends looking for PPF or PPFD (plant-usable light), not marketing watts alone. In practice: start with the distances below, watch the plant for two weeks, then move the light closer if stems stretch or farther if leaves bleach.
| Plant type | Start distance | Hours / day |
|---|---|---|
| Low-light foliage (snake plant, ZZ) | 18-24 in | 10-12 |
| Most houseplants (pothos, philodendron, Monstera) | 12-18 in | 12-14 |
| Sun-lovers (olive, croton, herbs) | 6-12 in (higher-output light) | 14-16 |
Ranges adapted from UMN and Iowa State Extension guidance on supplemental lighting. Total hours include daylight.
Photoperiod and timers
Plants need a dark period. Iowa State Extension advises plugging supplemental lights into a timer and keeping lights on no more than about 16 hours. A $10 outlet timer prevents “forgot to switch off” nights. Outlet timers on Amazon
Rough electricity cost
LED watts × hours × your kWh rate. Example assumption (disclosed): a 20 W bar on 14 hours at $0.16/kWh costs about 20×14×0.16/1000 ≈ $0.05 per day (~$1.50/month). Check the label’s actual watts; we have not metered specific models.
Plant-specific next reads
- Grow lights for Monstera
- Indoor herb garden with grow lights
- Olive tree and fiddle-leaf fig usually need lights indoors unless the window is very bright.