LM281B 150W Quantum Board LED Grow Light – Dimmable, VEG/BLOOM Switch

Full spectrum. VEG and BLOOM modes. Silent, fanless growing.

The LM281B 150W quantum board is a single-panel LED grow light built for people who want one light to carry a plant from seedling to harvest — without a fan humming in the corner, without a separate control box on the wall, and without needing to learn a spectrum chart to use it.

Its LM281B diodes are spread across a wide, flat board rather than packed into one hot point, so light lands evenly across the canopy instead of scorching the centre and starving the edges. A VEG/BLOOM switch shifts the spectrum to suit the growth stage, and the dimmer lets you ease off for young plants and wind it back up as they fill out. It suits a 2x2 tent, a shelf of propagation trays, a greenhouse bench or a spare-room grow.

Key Features

• ✅ VEG/BLOOM spectrum switch — VEG mode switches the 660nm deep red and 730nm IR diodes off for compact, controlled early growth. BLOOM mode switches them on to push flowering and fruiting.
• ✅ LM281B horticultural diodes — a mid-power grow diode chosen for output per watt rather than raw brightness, so more of your electricity ends up as usable light.
• ✅ Dimmable — turn the intensity down for seedlings and fresh cuttings, up for established plants, without moving the light or changing its height.
• ✅ Silent and completely fanless — the driver sits outside the panel, so heat leaves the board passively. No fan means no noise, nothing to clog with dust and nothing to wear out.
• ✅ Full spectrum with UV and IR — broad white light plus 660nm deep red, 730nm infrared and a small ratio of UV, so the plant gets the whole range rather than the old blurple two-tone.
• ✅ Wide, even coverage — a large flat board spreads light across the footprint instead of concentrating it into a single bright hot spot.
• ✅ Self-contained — hang it, plug it in, pick your mode. There's no ballast to mount and no app to set up.
• ✅ CE, RoHS and CCC certified — runs on 110–240V mains, with a protected circuit design to keep the diodes safe.

Why the VEG/BLOOM switch matters

Plants don't want the same light all the way through their lives. In early growth, a heavy dose of deep red and infrared encourages plants to stretch — they reach for the light and end up tall, leggy and weak-stemmed. Later on, when the plant is setting flower or fruit, that same deep red is exactly what you want, because it's the part of the spectrum that drives the flowering response.

Most cheap panels give you one fixed spectrum and expect the plant to cope. This one gives you two. Flick to VEG and the 660nm and 730nm diodes go off, leaving a white-dominant spectrum that keeps young plants short, bushy and strong. Flick to BLOOM when they're ready and those diodes come back on to drive the flowering stage. It's one switch, and it's the difference between a plant that stretches and one that builds structure first.

Coverage & Placement

These are recommendations based on the standard rule of 30–40W of actual power draw per square foot for flowering, and roughly half that for vegetative growth. They aren't manufacturer specifications — treat them as a sensible starting point and adjust by watching your plants.

• Flowering and fruiting: around 60 × 60cm (2ft × 2ft) at full power
• Vegetative and leafy growth: up to around 90 × 90cm (3ft × 3ft)
• Seedlings, cuttings and propagation: larger area still — dim it down and raise it up
• Starting height: roughly 45–60cm above the canopy at full power, then adjust

If leaf tips start bleaching or curling upward, the light is too close or too strong. If plants stretch toward it, it's too far or too dim. Adjust one thing at a time and give the plants a few days to answer.

Perfect For

• 2x2 grow tents and small grow cupboards
• Propagation shelves, seedling trays and cuttings
• Greenhouse benches and supplementary winter light
• Herbs, salad leaves, chillies, tomatoes and microgreens
• Houseplants and tropicals in dark rooms
• Hydroponics, coco, soil and pipeline cultivation alike

Specifications

What's in the Box

• 1 × LM281B quantum board LED grow light panel
• 1 × external driver with mains lead (EU or US plug, as selected)

Good to Know

• The UV diodes look dim. That's normal and expected — UV output is deliberately a small part of the spectrum, and your eyes barely register it.
• Plug type: this light ships with an EU or US plug. UK customers will need a standard plug adapter.
• Not waterproof. Indoor use only. Keep the panel and driver clear of misting, spray and condensation drip.
• Give the driver air. It sits outside the panel on purpose — don't bury it under bedding, tuck it behind ducting or wrap it in anything.
• Don't stare at it. At full power it's genuinely bright. Look away when you switch it on, and wear sunglasses if you're working under it for a while.
• Hang it level. An angled board throws an uneven footprint and you'll see it in uneven growth.

One panel, two spectrums, no noise — from first true leaves to final flower.

Not sure yet? Read the guides

We wrote guides that mention this exact product, with no sales pitch and no prices — just the answer.

• LM301H EVO vs LM281B: Which LED Board Should You Buy?
• Is a cheap grow light from a marketplace any good?

Orders are processed within 3 days, then 7–14 business days to arrive. You'll receive tracking as soon as your parcel ships.

Changed your mind? Return unopened items within 30 days for a full refund.