How long do LED grow lights last? Quality LED grow lights are commonly rated around 50,000 hours before output falls to about 70% of new, according to Oklahoma State University Extension. At 16 hours a day that’s roughly 8.5 years; at 12 hours, about 11 years. Heat, drive current and the driver usually decide real-world life, so a fixture can dim or fail sooner.
Key takeaway: How long do LED grow lights last depends on heat and build quality more than the diodes. Look for a stated L70, L90 or Q90 rating, keep the fixture cool and replace it when your plants’ light needs aren’t met.
| Light type | Typical rated life | Source |
|---|---|---|
| LED | Up to 50,000 h (to ~70% output) | Oklahoma State |
| HID (metal halide/HPS) | 24,000 h | Oklahoma State |
| Fluorescent | 10,000 h | Oklahoma State |
| Incandescent | Hundreds of hours | Oklahoma State |
How Long Do LED Grow Lights Last on Paper? What Does 50,000 Hours Mean?
It usually means an L70 rating: the point where the fixture produces 70% of its original output. Oklahoma State Extension explains that LEDs don’t burn out like bulbs; they gradually dim. A 2020 review in Horticulture Research by Kusuma, Pattison and Bugbee notes a typical L70 for LED fixtures is 50,000 hours and that horticultural products sometimes call it Q70, because plants respond to photons rather than lumens. So how long do LED grow lights last really asks: when will output drop too low for your crop?
How Long Do LED Grow Lights Last in Years?
Divide rated hours by your daily run time. Using a 50,000-hour rating:
| Hours on per day | Typical crop | Years to rated life |
|---|---|---|
| 12 | Flowering short-day plants | About 11.4 |
| 14 | Fruiting crops | About 9.8 |
| 16 | Lettuce, herbs, microgreens | About 8.6 |
| 18 | Seedlings, long-day crops | About 7.6 |
These are math estimates, not guarantees. Ratings come from tests at stated temperatures, and your grow tent may be hotter. See our light schedule guide for crop photoperiods.
How Long Do LED Grow Lights Last by L70, L90 and Q90?
- L70 / Q70: Hours until output falls to 70% of initial.
- L90 / Q90: Hours until output falls to 90% of initial. A stricter, shorter number.
- Q prefix: The DesignLights Consortium (DLC) uses “Q” for photon-based output (PPF, 400–700 nm) instead of lumen-based “L.”
DLC’s horticultural requirements call for a Q90 of at least 36,000 hours within the 400–700 nm range. Its earlier testing document explains the 10% threshold: plant growth is sensitive to reduced light, and growers generally replace lighting beyond that level of decline. A DLC-listed fixture tells you the rating was tested to a standard.
How Long Do LED Grow Lights Last in Real Life?
Kusuma and colleagues list several causes that shorten real life:
- Heat: LEDs degrade as a function of temperature and current density; high junction temperatures speed the decline.
- Driver failure: The review notes that the LED driver often fails before the LEDs reach L70.
- Overstated claims: Projections from standard LM-80 diode testing can’t exceed six times the test duration, and the authors say many extended-lifetime claims break that rule.
- Optical losses: Lenses and covers that yellow or collect dust cut output, which diode ratings don’t include.
How Long Do LED Grow Lights Last Before You Should Replace Them?
Measure, don’t guess. A PAR meter or a calibrated phone app shows how many photons reach the canopy. Record readings at fixed points when the light is new and recheck every few months. Our guide to measuring canopy PPFD covers the method. Signs your light is fading:
- PPFD down 10–30% at the same hanging height
- Leggy, stretching seedlings that used to grow compact
- Dead or flickering diodes or strips
- A noisy or failed cooling fan
How Long Do LED Grow Lights Last Compared With Other Lights?
According to Oklahoma State’s comparison table, LEDs last about twice as long as HID lamps (24,000 hours) and five times as long as fluorescent (10,000 hours). Incandescent bulbs last only hundreds of hours. LEDs also use the least energy of these options. The higher purchase price is spread across many more years of use.
How Long Do LED Grow Lights Last With Good Care?
- Keep them cool: Oklahoma State notes heat leaves through the heat sink, so keep fins clean and give the fixture airflow.
- Control room temperature: Run a tent fan; heat is the main aging factor.
- Don’t run at 100% if you don’t need to: Lower current density reduces stress. Dim to the level your crop needs.
- Clean lenses and diodes gently with a dry, soft cloth when the light is off and cool.
- Protect the driver: Keep it away from water spray and reservoirs, and use a surge-protected power strip.
- Use a timer so lights don’t run longer than needed.
Our electrical safety guide covers drivers and humidity.
How Long Do LED Grow Lights Last Before Efficiency Drops?
Yes, in effect. Kusuma and colleagues note that as LEDs and fixtures age, efficacy declines, and high junction temperatures make it worse. The fixture draws roughly the same watts while delivering fewer photons, so your cost per mole of light rises over time. That’s another reason to measure canopy light once or twice a year. When output falls enough that you’d need to lower the light or extend hours to hit your crop’s target, compare the running cost with a new, more efficient fixture. See PPFD and DLI for setting targets.
How Long Do LED Grow Lights Last if You Switch Them Daily?
Oklahoma State notes that LEDs switch on and off instantly as solid-state semiconductors. Unlike HID lamps, they don’t need warm-up or cool-down. Daily timer cycles are normal for grow lights, and the fixture’s rating already assumes regular operation. Total hours and heat matter far more.
What Should You Check Before Buying a Long-Lasting LED Grow Light?
- A published L70, L90 or Q90 rating with test temperature
- DLC horticultural listing for larger fixtures
- Passive cooling (heat sink) or a replaceable fan
- A separate or replaceable driver
- Warranty length, which reflects how long the maker expects it to last
For buying basics, read our grow lights guide.
FAQs
Do LED grow lights lose spectrum over time?
Different diodes can age at different rates, so the color mix may shift slightly; measuring output tracks the change.
Can I replace just the driver?
On many fixtures with external drivers, yes. Check the manufacturer’s guidance.
Do cheap LED grow lights last 50,000 hours?
Not necessarily. Without a tested rating and good heat management, real life can be far shorter.
Should I raise light intensity as it ages?
You can lower the light or extend the photoperiod slightly to keep daily light the same.
How long do LED grow lights last in a hot grow tent?
Less than the rating, since heat speeds LED decline.
Sources
- Oklahoma State University Extension — LED Grow Lights for Plant Production (HLA-6450)
- Kusuma, P., Pattison, P.M., Bugbee, B. (2020). From physics to fixtures to food: current and potential LED efficacy. Horticulture Research 7:56.
- DesignLights Consortium — Technical Requirements for LED-Based Horticultural Lighting V3.0
- DesignLights Consortium — Testing and Reporting Requirements for Horticultural Lighting V1.2
- Photo credits (Wikimedia Commons, edited with titles): Terramera scientists working in a climate-controlled growth chamber located in Vancouver, BC. The space uses LED lighting, which supports plant growth. (50188965171) by Simon Fraser University – Communications & Marketing (CC BY 2.0); Led digital visuals-leds in grow box PNr°0082 by D-Kuru (CC BY-SA 3.0 at); Moscow, Novospassky Bridge – LED floodlights – heatsinks 02 by Retired electrician (CC0); Potted plants succulents under grow light Nov 2016 by Asdfjrjjj (CC BY-SA 4.0); U.S. Department of Agriculture (USDA) Rural Development (RD) Ohio business program staff visited Mucci Farms, a 75-acre greenhouse production farm in Huron, Ohio on September 25, 2024 – 2 by USDAgov (Public domain)