LED Grow Lights: Full-Spectrum Fixtures From 120 W to 480 W

Watts don't tell you how bright a light is. Wattage is what the fixture pulls from the wall, and a "1000 W" panel on a marketplace listing is often just a headline number with no photon figure behind it. The two specs that tell you something real are PPF, measured in µmol/s, and efficacy, measured in µmol/J. All four Phytonaut fixtures publish both, which is why we keep pointing growers at them.

What PPF and Micromoles Per Joule Actually Mean

PPF is the total usable light a fixture puts out every second. The Phytonaut 120 W gives 330.69 µmol/s, the 240 W gives 697.10 µmol/s, the 320 W gives 927.64 µmol/s, and the 480 W gives 1415.33 µmol/s. Efficacy tells you how much of that you get per unit of electricity: 2.74 µmol/J on the 120 W, 2.82 on the 240 W, 2.83 on the 320 W, and 2.9 on the 480 W. When two lights sit in the same wattage class, efficacy is the number that separates them, so it's worth reading before anything else in the growshop.

From a Small Space to a Bigger Room: Matching Watts to Your Space

The 120 W is the smallest fixture in the Phytonaut range and is the small-space option, where weak corners cost you more than centre intensity. The 240 W steps up to medium grows that need full-cycle light from seedling to harvest. The 320 W suits bigger plant counts and longer cycles, and the 480 W is the full-room end of the ladder, with the best efficacy of the four. If you'd rather run a Pure Factory fixture, the Pure LED Q320 is a 320 W light with a 54 cm frame at 5.6 kg, and the Q420 is 420 W across 62 cm, up to 6.4 kg, with a 150 cm cable. Both Pure LED boards are built on Samsung LMB281+ PRO diodes plus Honglitronics SMD3535 chips, are IP 65 rated and hold a power factor above 0.90. That weight is real in the hand, so check your rope ratchets and tent bars before you hoist it.

120 Degrees, Hanging Height and Dimming Down for Seedlings

Every Phytonaut has a 120 degree beam angle, which pushes light out to the edges instead of stacking it in one hotspot in the middle. Hanging height does the rest of the work, and the documented canopy distances are the same across the range:

• Seedling or clone: 90 cm
• Vegetative: 60 cm
• Flowering: 40 cm

Leaves curling or bleaching means the light is too close, so raise it. Stretchy growth means it's too far, so drop it. Dimming is continuous on the rotary knob on the driver, from OFF to full power, and the fixtures also support 0 to 10 V external dimming systems if you want the Zamnesia Grow Environment Controller running the schedule. Watch out for two things: that controller is sold separately, and a short tent won't always give you the 90 cm of headroom a seedling wants.

Which of the Seven We'd Hang

Passive cooling means no fans on the Phytonaut fixtures, so the only thing you'll hear in the tent is your extraction. The diodes are Sanan and Osram chips, and IP65 splash resistance and a rated life of at least 54,000 hours cover the humid end of indoor growing. On paper the Phytonaut 320 W and the Pure LED Q320 are both 320 W lights, but we can quote 927.64 µmol/s and 2.83 µmol/J for the Phytonaut, while the Q320's documented specs are its wattage, frame size, weight, diodes, IP 65 rating and power factor. If you want numbers to plan a canopy around, the Phytonaut range is where they live. First light for a small space, take the 120 W. Running a full cycle in something larger, the 480 W at 2.9 µmol/J is the most efficient light on this page.