Fertraso - 250W HPS Lamp

This 250 watt high pressure sodium lamp gives warm light at 2000 kelvin and 30,000 lumen initially, with an E40 cap and a nominal life of 28,000 hours.

A lumen is not a grow-light measurement

Almost every HID lamp is sold on lumens, this one included. It is an honest number, it just does not measure what you want to know. The lumen was devised to describe how bright light looks to a HUMAN, and a human eye is most sensitive to green. Precisely the colour a plant does least with.

The result is a systematic bias. Sodium light is yellow and orange, close to the peak of the human eye, so an HPS scores highly in lumens. Metal halide is bluer, further from that peak, and scores lower while a plant in vegetative growth actually gets on better with it. Comparing two lamps on lumens therefore ranks them wrongly as soon as their colour differs.

What you would compare on instead is PAR, expressed in micromoles per second, because that counts the particles of light a plant can use. The trouble in this corner of the market is that hardly any HID manufacturer publishes that figure. So we repeat the lumens as given, because you will meet them elsewhere too, but build no argument on them.

Compare within the same type and colour and the lumen becomes useful again: between two 250 watt HPS lamps the number does tell you something.

Technical Specifications:

• Model: 21.218
• Power: 250 W
• Type: high pressure sodium, HPS
• Colour temperature: 2000 K, warm
• Luminous flux: 30,000 lumen initial, 27,000 lumen after run-in
• Cap: E40
• Life expectancy: nominally 28,000 hours
• Ballast: required, not included

Frequently asked questions

Why is there no micromole figure on this lamp?
Because the manufacturer does not publish one. With HID lighting that is the rule rather than the exception.

Can I compare it to an LED on lumens?
Better not. Lumens measure what a human eye sees, not what a plant uses.

Do I need a ballast?
Yes. An HID lamp will not run without one and it is not included.

Is this a growth or a flowering lamp?
Flowering. The warm 2000 kelvin light belongs to that stage.