How far should LED grow lights be from plants? Close enough to maximise photosynthesis, but far enough to avoid heat stress or light burn — and that sweet spot shifts as your plants move through each growth stage. Get the distance wrong in either direction and you'll either stunt growth from too little light, or damage leaves from too much. This guide covers the general distance ranges for each stage, how light intensity changes those numbers, and the warning signs to watch for if your light needs to move.
Correct LED grow light distance by growth stage 💡
Where your light should sit depends on the plant, its growth stage, and the intensity of the fixture itself. The ranges below are a general starting guide — always check the manufacturer's own recommendation for your specific light, since output varies significantly between models.
| Growth stage | Distance | Status | Notes |
|---|---|---|---|
| Seedling | 60–90cm | Start here | Delicate seedlings stress easily; start further back and lower gradually |
| Vegetative | 45–60cm | Move closer | More light drives faster photosynthesis and growth |
| Flowering | 30–45cm | Closest point | Highest light demand, but watch closely for burn |
💡 A-Grade Tip: Move your light down gradually over a few days rather than all at once, and check the canopy the next morning before adjusting further. Plants generally show stress within 24–48 hours if a light's been moved too close.
Why light intensity changes the distance 📏
The wattage and output of your fixture matters just as much as the growth stage. A high-intensity light — say, a 1000W-equivalent system — should sit toward the upper end of these ranges to avoid light burn, since it's putting out far more photosynthetic photon flux density (PPFD) at any given distance. A lower-intensity fixture, such as a 200W LED, can generally sit at the closer end of the range without causing harm.
If you're upgrading to a more powerful light or trying a new model for the first time, always start with the manufacturer's recommended hanging distance rather than assuming your old light's distance still applies — output varies significantly between brands and diode types even at the same wattage rating.
Signs your grow light is too close 🌱
Most plants show visible stress within a day or two if a light sits too close, whether from excessive intensity or the heat the fixture generates. Keep an eye out for:
- Leaf burn — brown or crispy patches, usually starting at leaf tips and edges
- Yellowing leaves — a loss of vibrant colour, often an early stress signal
- Stunted growth — noticeably slower development despite otherwise good conditions
- Wilting — in more severe cases, plants can wilt even when watering is adequate
If you spot any of these, raise the light a few centimetres and reassess after a day or two rather than making a large adjustment all at once.
Getting LED grow light distance right is mostly about matching the range above to your fixture's actual output, then watching your plants for feedback as they move through each stage. Browse A-Grade Hydroponics' full range of dimmable and app-controlled LED grow lights, or get in touch with our Melbourne team if you'd like help matching a light to your space.
