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Pairs well with
The Plantmax 400W High Pressure Sodium Lamp delivers the warm red-orange spectrum plants need to push hard through bloom. Built around a robust T46 tubular envelope with an E40 mogul base, this is a flowering workhorse for smaller grow rooms and tents — covering up to 1.5m x 1.5m with a properly sized reflector. Pumps out 50,000 lumens, runs on both magnetic and digital ballasts, and lasts 24,000 hours of operation.
Specifications
- This is a single-ended lamp with an E40 mogul base — fits any standard SE reflector. Not for double-ended (DE) fixtures.
- Wattage must match exactly. A 400W lamp needs a 400W ballast — never run on lower or higher wattage settings.
- Always operate in a properly ventilated reflector — HID lamps run hot and need adequate airflow.
- Always handle with clean gloves or a soft cloth. Skin oils on the quartz cause hot spots and shorten lamp life.
- Never restart a hot lamp. Wait at least 10 minutes after power-off before re-igniting.
- Allow 3–5 minutes for the lamp to reach full brightness — that's normal warm-up time for a discharge lamp.
How To Use
Pairs Well With
Browse 400W HPS ballasts — both magnetic and digital electronic options compatible with this lamp.
Ultra-Lite Reflector by SeaHawkSingle-ended bat-wing reflector rated for 250–1000W HID — fits this lamp's E40 mogul base perfectly.
Inline Exhaust Fans400W HPS still puts out heat — pair with a properly sized fan to keep canopy temps in check.
Rope Ratchets by Cultiv8Adjust hang height easily as plants stretch through bloom — keep optimal canopy distance day by day.
Frequently Asked Questions
Will this lamp run on a digital ballast?
Yes. The Plantmax 400W HPS is designed to run on both magnetic and digital electronic 400W HPS ballasts. Make sure the ballast wattage matches the lamp wattage.
Is this single-ended or double-ended?
Single-ended (SE) with an E40 mogul base. Fits any standard 400W SE reflector — not for double-ended (DE) fixtures with K12x30s sockets.
Can I use this lamp for veg as well as flower?
Yes, but it's better suited to flower. HPS skews red-orange and is built for blooming, but it'll handle late veg into bloom. For early veg, most growers prefer a Metal Halide spectrum to keep nodal spacing tight, then switch to HPS for flower.
What size space does a 400W HPS cover?
A 400W HPS comfortably covers a 1.2m x 1.2m flowering footprint, or up to 1.5m x 1.5m for veg or supplemental lighting. Hang at 30–60cm above the canopy and adjust as plants grow into the light.
How long does this lamp last?
Rated 24,000 hours of operation. Most growers replace 400W HPS lamps after 12 to 18 months of regular cycle use. Watch your canopy — softer growth and looser flower density are signs the lamp is fading.
Why does it take time to reach full brightness?
HPS is a discharge lamp — it takes 3–5 minutes to reach full output as the gas fill ionises and the arc tube reaches operating temperature. The lamp may appear dim during warm-up. That's normal.
Does it come with a warranty?
Yes. Plantmax backs every lamp with a one-year limited warranty against defects. Keep your packaging and proof of purchase in case you need to make a claim.
Do you ship Australia-wide?
Yes — we ship across Australia from our Tasmanian base. Free shipping kicks in over $499*. HID lamps are packed carefully to handle transit, but if anything arrives damaged, give us a yell and we'll sort it.
Bloom-Tuned Output. Sensible Power Bills.
50,000 lumens of red-spectrum HPS for flowering — the right size for tents and small grow rooms.