Horticulture Lighting Group (HLG) LED Grow Lights
Horticulture Lighting Group (HLG) pioneered the quantum board LED format for horticultural growing and remains one of the most recognized brands in the hobby and small commercial LED grow light market. Their fixtures use Samsung LM301B and LM301H quantum board designs -- large circuit boards densely populated with small, high-efficiency LED diodes that distribute light evenly, run at low junction temperatures for long lifespan, and achieve efficiencies of 2.5-2.9+ umol/joule depending on model. HLG's product line covers the full range from small 65W propagation panels to the 650R and Scorpion commercial bar arrays for large canopy flowering production.
HLG Quantum Board Line
HLG's quantum board fixtures -- the HLG 100, HLG 300, HLG 550, and V2/V3 series -- are the fixtures that established the quantum board format in the hobby growing community. The HLG 300 V2 (300W) is one of the most widely documented and reviewed grow lights in online growing communities, with thousands of reported grows at multiple scales providing real-world performance data. The HLG 550 V2 (500W) covers a 4x4 ft flowering canopy at commercial PPFD levels. All quantum board models include dimming capability via onboard dial, and select models support external 0-10V dimming for controller integration with TrolMaster and other compatible systems.
HLG Scorpion & 650R -- Commercial Bar Arrays
HLG's Scorpion and 650R lines move from the quantum board panel format to a bar array design for commercial-scale canopy coverage. The HLG 650R (650W) uses a six-bar array configuration to cover a 4x4 to 5x5 ft flowering canopy with better uniformity than equivalent panel designs. The Scorpion series scales to 1,000W+ for 5x5 to 6x6 ft canopy applications. Both lines use HLG's R-spec spectrum (adding deep red 660nm and far-red 730nm to the quantum board white spectrum) for optimized flowering response. For a comparison of HLG against Faven Lighting and Gavita, see our updated best LED grow lights guide. Expert support available.
HLG Grow Lights FAQ
What is a quantum board LED and why did HLG pioneer it?
A quantum board LED is a large printed circuit board densely populated with many small, high-efficiency LED diodes rather than concentrating output at a single point or a few high-powered COBs. HLG popularized the format for horticulture because quantum boards produce better canopy uniformity, run at lower junction temperatures (extending LED lifespan), and achieve higher efficiency than the COB and blurple designs they replaced. Samsung LM301B and LM301H diodes -- which HLG uses across their product line -- set the benchmark for efficiency in the 2.5-2.9+ umol/joule range when introduced and remain among the top-performing horticultural LED emitters available.
What is the difference between HLG quantum board panels and the Scorpion/650R bar arrays?
HLG's quantum board panels (HLG 100, 300, 550 series) use a single large board as the light source -- well-suited for 2x2 to 4x4 canopy sizes with straightforward installation. The Scorpion and 650R bar arrays use multiple bars distributed across the fixture frame for better canopy uniformity over larger footprints -- the bar format reduces the center-to-edge PPFD gradient that single-board panels produce over 4x4 and larger canopies. For 2x2 to 3x3 grows, the quantum board panels deliver excellent results at lower cost than the bar arrays. For 4x4 and larger commercial flowering applications, the Scorpion and 650R provide the uniformity advantage that makes bar arrays the commercial standard.
Can HLG lights be dimmed?
Yes -- all current HLG fixtures include dimming capability. Quantum board models (HLG 100, 300, 550 and V2/V3 series) include an onboard dimming dial that adjusts output from approximately 50-100%. The Scorpion and 650R bar arrays support external 0-10V dimming for controller integration via a dimming cable, enabling automated dimming schedules through TrolMaster Hydro-X or other compatible 0-10V controllers. External 0-10V dimming allows precise schedule management -- sunrise/sunset ramping, temperature-triggered dimming, and remote adjustment via controller app -- without manual adjustment at each fixture.
What size HLG light do I need for a 4x4 tent?
For a flowering 4x4 canopy, the HLG 550 V2 (500W) or HLG 650R (650W) are the standard recommendations. The HLG 550 V2 achieves approximately 900-1,000 umol/m2/s PPFD across a 4x4 canopy at 18-24 inch hanging height -- adequate for productive flowering for most crops. The HLG 650R at 650W provides higher PPFD (1,000-1,200+ umol/m2/s) with better uniformity across the 4x4 footprint due to its bar array design. For vegetative growth only in a 4x4, the HLG 300 V2 (300W) provides adequate PPFD at the 400-600 umol/m2/s vegetative target. Use our PPFD Calculator with the published HLG PPFD maps to confirm coverage for your specific hanging height.
