Pure LED Q420 Grow Light (Pure Factory)

Pure LED Q420 Grow Light — 420W Full-Spectrum Power for Large Grow Rooms

The Pure LED Q420 is a 420W full-spectrum LED grow light from Pure Factory, built to drive serious harvests in tents and rooms measuring 120–150 cm. Packing 1,792 Samsung LM281B+ PRO diodes and 96 Honglitronics deep-red LEDs into a panel that weighs just 6.4 kg, it delivers 2.7 µmol/J efficiency — meaning more light energy reaches your canopy and less disappears as heat. If you're scaling up from a smaller setup or replacing an older HPS fixture, this is the lamp that makes the jump worthwhile.

What's Included with the Pure LED Q420

You get the complete lamp unit ready to hang and plug in — no ballast box, no reflector assembly, no fiddling with bulbs. Here's what comes in the box:

• Pure LED Q420 light panel (628 x 628 x 43 mm)
• Built-in manual dimmer dial
• Power cable (compatible with 100–277V AC)
• Hanging hardware (adjustable ratchet hangers)

The panel itself is surprisingly thin at just 43 mm. Pick it up and you'll notice how compact it feels for a 420W unit — 6.4 kg is light enough to hang from most tent crossbars without reinforcement. The passive cooling design means zero fan noise. Literally silent. We've had customers email us thinking the lamp wasn't on because they couldn't hear anything. It was on. It was just quiet.

Specifications for the Pure LED Q420

Why the Pure LED Q420 Deserves a Spot in Your Grow Room

Running a 120–150 cm tent with an underpowered light is like trying to fill a swimming pool with a garden hose. You'll get there eventually, but the results will be thin, stretched, and disappointing. The Q420 was designed specifically for this footprint — 420 watts spread across a 628 x 628 mm board gives you even coverage without the hot spots you get from smaller panels hung too high.

The Samsung LM281B+ PRO chips are the same diodes you'll find in grow lights costing significantly more. Samsung's binning on these is tight, which means consistent output across the board — no dim corners, no lottery on chip quality. The 96 supplemental Honglitronics 660nm deep-red LEDs are the detail that separates this from generic white-only quantum boards. That 660nm wavelength targets the peak absorption of chlorophyll A during flowering, which is exactly when you want every photon pulling its weight.

At 2.7 µmol/J, you're converting electricity into usable plant light at a rate that would have been science fiction ten years ago. For context, a traditional 600W HPS runs at roughly 1.7 µmol/J — so the Q420 gives you more photosynthetically active light while drawing 180 fewer watts from the wall. Over a full grow cycle, that electricity saving adds up fast.

One honest limitation: the 120° beam angle is wide, which is great for coverage but means you lose some intensity at the very edges of a 150 cm tent. If you're running a full 150 x 150 cm space and want absolutely uniform PPFD from wall to wall, you might consider the Pure LED Q600 or supplementing with side lighting. For a 120 x 120 cm tent, though, the Q420 is the best match in the Pure LED lineup — it fills that space beautifully without overspending on wattage you don't need.

Build Quality and Design Details

The Q420 is built on an aluminium heatsink frame that doubles as the entire housing. No plastic shrouds, no clip-on reflectors — just a solid slab of finned aluminium with the diode board mounted flush. Run your hand across the back while it's operating and it's warm, not hot. That's passive thermal management doing its job. No fans means no fan failures, no dust buildup on internal components, and no noise. At all. You could run this in a bedroom and sleep next to it.

The IP65 rating is worth flagging. Most LED panels top out at IP20 or IP40 — basically "don't breathe on it." IP65 means the Q420 is protected against water jets from any direction. In a humid grow environment where condensation drips and foliar spray mist drifts, that matters. We've seen cheaper panels develop corrosion around the driver connections within a single grow cycle. The Q420's sealed design avoids that entirely.

The manual dimmer dial on the side lets you wind the output down for seedlings and early veg, then crank it back to full for flower. If you're running multiple lights or want automated scheduling, the 0–10V signal input connects to any standard grow room controller — no proprietary adapters, no brand lock-in.

Comparison with Alternatives

If you're weighing up your options, here's how the Q420 stacks up against two other lights we carry for similar tent sizes:

The Q320 is the better buy if you're running a 100–120 cm tent — same efficiency, same chip quality, lower electricity bill. The Fission Compact 720W is for genuinely large rooms where 420W won't cut it. The Q420 sits in the sweet spot for the most popular tent size we sell: 120 x 120 cm.

How to Set Up the Pure LED Q420

1. Unbox the Q420 and attach the ratchet hangers to the mounting points on each corner of the panel. These clip in — no tools needed.
2. Hook the ratchet hangers to your tent's crossbar or ceiling mount. Adjust the height so the panel sits roughly 40–60 cm above your canopy for mature plants, or 80–100 cm for seedlings.
3. Plug the power cable into a standard outlet (100–277V AC — works across all EU voltages without an adapter).
4. Set the dimmer dial to your desired intensity. For seedlings and clones, start at 40–50%. For vegetative growth, 60–80%. For flowering, wind it up to 100%.
5. If you're using a 0–10V grow room controller, connect the signal cable to the input port on the driver. The lamp will then follow your automated light schedule and intensity curve.
6. Check your canopy temperature after 30 minutes. The Q420 runs cool, but in a sealed tent, ambient heat still builds. Aim for 24–28°C at canopy level with adequate air exchange.

From Our Counter: Real-World Notes

We've sold the entire Pure LED Q-series since it launched, and the Q420 is the one that moves fastest. Most customers running 120 x 120 cm tents land here after outgrowing a 240W or 300W panel — and the difference in flower density is immediately visible. The combination of 4000K white and 660nm red gives a warm, slightly pink-white light that doesn't make your plants look alien green under it. You can actually see what you're doing during inspections without needing a separate green headlamp.

The one thing we always mention: hang it level. Because the beam angle is 120° and the board is perfectly flat, even a slight tilt creates uneven coverage. Use a spirit level across the top of the panel after hanging. Takes ten seconds and makes a measurable difference to your canopy uniformity. We've seen growers blame "weak corners" on the lamp when it was actually a 3° tilt the whole time.

Frequently Asked Questions

Last updated: April 2026