How to Use Grow Lights Without Burning Your Plants
Distance, duration, and how to spot burn before it spreads.
Grow lights let you keep healthy houseplants in a dark corner — but too close or too many hours and you'll bleach or scorch the exact leaves you're trying to help. Three settings matter: distance, duration, and spectrum.
Get the Setup Right
Start 30–60 cm above the foliage. Move closer gradually over 1–2 weeks, watching for pale or bleached patches.
12–16 hours a day on a timer, mimicking a strong natural day with a real dark period at night.
A full-spectrum white LED suits most houseplants for balanced growth; avoid running pure blue/red only unless growing seedlings or fruit.
Bleached or crispy patches on the light-facing side of leaves, that stop spreading once you move the light back.
Grow Light FAQs
How close should a grow light be to my plant?
For a standard full-spectrum LED grow light, 30–60 cm above the foliage is a safe starting distance. Move it closer gradually over a week or two while watching for any bleaching or pale patches, rather than starting close.
How many hours a day should I run a grow light?
12–16 hours a day for most houseplants mimics a strong natural day. Use a timer so the plant gets a consistent dark period too — plants need darkness to complete their growth processes.
What does light burn look like?
Pale, bleached, or yellow-white patches on the leaves facing the light, sometimes with crispy brown centres — different from a nutrient deficiency because it appears specifically on the light-facing side and stops spreading once the light is moved back.
Does the colour/spectrum of the grow light matter?
Yes — a full-spectrum white LED (covering both blue and red wavelengths) suits most houseplants for balanced leaf and stem growth. Pure red/blue 'grow light purple' bulbs are more common for seed-starting or fruiting plants.
Can I leave a grow light on 24 hours a day?
No — plants need a dark period to process the sugars they produced during light hours. Constant light causes stress over time rather than faster growth.
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Track your light setup results
Log distance and hours in your diary, and watch how your plant responds over time.
