Osram 600W SON-T-PLUS Lamp - High-Output HPS Bulb for Flowering
Best for: Growers running a 600W HPS ballast and reflector who want a reliable, high-output flowering lamp without paying for LED.
Our thoughts
HPS lamps like this one are still doing serious work in flowering rooms up and down the country, and there's a reason - proven output, proven reliability, and a price point LED fixtures still can't match on a like-for-like basis. This is a bulb, not a fixture, so you'll need a compatible ballast and reflector, but if you've already got those, this is a straightforward, dependable choice.
The Osram (Vialox Nav-T Super) 600W SON-T-PLUS is a single-ended high-pressure sodium (HPS) lamp built for the flowering stage, putting out a heavily red/orange-weighted spectrum that plants respond to strongly during bloom. It's a bulb only - it needs a compatible 600W HPS ballast and a reflector to run, it doesn't come as a complete fixture.
SON-T-PLUS lamps have a strong reputation in the HPS category for lumen output and lifespan. This one is rated at around 90,000 lumens with an efficacy of roughly 150 lumens per watt, among the higher outputs you'll find in a 600W HPS lamp, and Osram rates it for approximately 32,000 hours of life - slightly longer than many standard HPS lamps in this wattage.
How it compares
Within the 600W single-ended HPS bracket, the SON-T-PLUS competes on raw lumen output and longevity rather than novelty features.
- Philips' equivalent Master GreenPower Son-T PIA CG-T 600W/230V lamp is rated slightly lower on lumen output (around 88,000 lumens) but has a longer rated life (around 24,000 hours vs Osram's stated 32,000, depending on source and testing conditions).
- Compared with a 600W LED fixture, the SON-T-PLUS costs a fraction of the price up front but draws more power for a given canopy footprint and runs hotter, which matters for room cooling.
- Within HPS specifically, this lamp's ~150 lm/W efficacy is towards the top end of what standard single-ended 600W HPS lamps achieve.
If you're already invested in an HPS ballast and reflector and just need a dependable flowering bulb, this is one of the stronger performers in its class rather than a budget compromise.
Usage guidance
This lamp requires a compatible 600W HPS ballast (magnetic or digital) and reflector - it will not run on its own.
Fitting
Screw into an E40 fitting connected to your ballast and reflector. Handle by the ceramic base, not the glass envelope, to avoid contamination that can shorten lamp life.
Hanging height
Hang high enough above the canopy to avoid heat stress - typically 30-60cm depending on your reflector and room ventilation, adjusting based on leaf temperature.
Replacement timing
HPS lamps lose usable PAR output well before they fail completely, so most growers replace them annually even though the rated life is longer, to avoid running a dimming bulb through a full flowering cycle.
Technical specifications
- Lamp type: Single-ended high-pressure sodium (HPS)
- Wattage: 600W
- Lumen output: Approx. 90,000 lm
- Efficacy: Approx. 150 lm/W
- Rated lifespan: Approx. 32,000 hours
- Fitting: E40
- Spectrum: Red/orange-weighted, optimised for flowering
- Requires: Compatible 600W HPS ballast and reflector (sold separately)
- Brand: Osram
Who this is for
- Growers with an existing 600W HPS ballast and reflector who need a replacement or upgrade bulb
- Anyone prioritising proven flowering output and lamp longevity over LED's higher upfront cost
- Budget-focused growers who want strong lumen output without switching lighting technology
- Growers who prefer the well-established reliability of HPS for bloom
Not suitable as a standalone light source - you'll need the ballast and reflector to go with it.
Our take
HPS 600W lamps like this are a known quantity - reliable, high-output, and priced sensibly compared with switching to LED. Osram's SON-T-PLUS holds its own against the usual Philips comparison on both lumen output and lifespan, and it does the job flowering rooms have relied on for years.
One we sell a lot of for new growers who already have HPS kit and just need a dependable bulb. Worth picking up if you want dependable lighting that performs consistently.
