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Bulb HPS/MH 400 Watt

400W HPS and MH grow bulbs for 1m² indoor setups

Roughly 50,000 lumens from a single bulb, a footprint of 1 to 1.5 square metres, and heat output that stays manageable with a mid-range extractor — those numbers explain why the 400W HPS bulb remains the reference wattage for serious indoor growers. Ideal for grow tents from 100×100 cm to 120×120 cm.

Our 400W range covers every approach: Philips GreenPower and Sylvania Grolux as dual-spectrum HPS for single-bulb cycles, Lumatek HPS for pure bloom output, Lumatek MH for vegetative growth, and Superplant Super Red as a value alternative. Fast, discreet delivery across Belgium.

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Sylvania Grolux 400W patented arc tube photosynthetic HPS | Bulb HPS/MH

Sylvania Grolux 400 Watt

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Philips Greenpower 400W HPS vegetables flowers grow bulb | Bulb HPS/MH

Philips Greenpower 400 Watt

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Lumatek HPS 400W high-par European engineered grow lamp | Bulb HPS/MH

Lumatek HPS 400 Watt

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Lumatek MH 400W growth lamp ultra high frequency electronic | Bulb HPS/MH

Lumatek MH 400 Watt

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Superplant Super Red 400W HPS grow lamp product photo | Bulb HPS/MH 400W

Superplant Super Red 400 Watt

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Our 400 Watt HPS and MH grow bulb range

The 400W bulb is the most practical choice for a serious single-tent indoor grow. It covers a full square metre with plenty of light intensity, runs cool enough for standard ventilation, and costs noticeably less to run than 600W or 1000W alternatives. See our full HPS/MH bulb range for all wattages, or pair your bulb with a matching 400W ballast.

Why 400W hits the sweet spot for indoor growers

Ask a room full of experienced growers which wattage they would recommend for a first serious tent and the majority will point to 400W. The maths works: around 50,000 to 58,000 lumens from a quality HPS bulb, enough to drive flowering across a full 1 m² canopy, without the climate control headaches of higher wattages. A 400 to 600 m³/h extractor handles the heat in a standard 100×100×200 cm tent. For 600W you would typically need 600 to 800 m³/h and a more robust cooling strategy.

HPS bulbs: single-spectrum or dual-spectrum?

HPS bulbs split into two camps. Pure bloom bulbs focus their output in the orange-red range for maximum flowering intensity — that is the territory of the Lumatek HPS 400W and Superplant Super Red 400W. Dual-spectrum HPS bulbs add roughly 30% more blue to that base, making them usable through vegetative growth as well. The Philips GreenPower 400W and Sylvania Grolux 400W both fall into this category. Both are HPS technology — the Grolux is not an MH bulb despite occasional mislabelling online.

MH for the veg phase — Lumatek MH 400W

If you prefer the traditional two-bulb approach (MH for veg, HPS for bloom), the Lumatek MH 400W is the go-to veg bulb. Pulse-start technology for faster warm-up and longer life, 40,000 initial lumens in the 4200K (cool white) version or 35,000 lumens in the 6000K (daylight) version, and a PPF of 518 µmol/s. The blue-heavy spectrum drives compact vegetative growth with short internodes and broad leaves — the kind of sturdy plant architecture that supports heavy flowering later.

Quick reference — what each 400W bulb does best

Philips GreenPower 400W: dual-spectrum HPS, ~58,000 lumens, the commercial greenhouse benchmark.
Sylvania Grolux 400W: dual-spectrum HPS, ~55,000 lumens, 2050K, 145 lm/W efficiency.
Lumatek HPS 400W: single-spectrum bloom HPS, optimised for Lumatek digital ballasts.
Superplant Super Red 400W: bloom-focused HPS, enriched red spectrum, budget-friendly.
Lumatek MH 400W: metal halide, 35,000-40,000 lumens, PPF 500-518 µmol/s, pure vegetative.

Practical setup and replacement schedule

Hang your 400W bulb 40 to 50 cm above the canopy with an open reflector, or drop to 25-30 cm with an air-cooled cooltube reflector. The back-of-hand test still works: if the heat at plant level is uncomfortable on your skin, it is too much for your plants. For a plug-and-play installation, the 400W lighting kit bundles ballast, bulb and reflector. Replace the bulb every 12 to 18 months to maintain peak output — lumen flux drops 15-20% after this period without clear visual signs.

FAQ - Frequently asked questions about 400W bulbs

Is the Sylvania Grolux 400W an HPS or MH bulb?

The Grolux 400W is an HPS (high-pressure sodium) dual-spectrum bulb, not MH. It emits roughly 30% more blue light than standard HPS, making it usable for both vegetative and flowering stages. Output is around 55,000 lumens with a 2050K colour temperature.

What is the difference between Philips GreenPower and Lumatek HPS 400W?

Both are professional-grade HPS bulbs. The Philips GreenPower adds 30% extra blue to its red-orange spectrum, making it particularly effective for extended vegetation — it is the reference in commercial greenhouses. The Lumatek HPS is tuned for stability with Lumatek digital ballasts and focuses on bloom-phase output. Both produce 55,000 to 58,000 lumens.

Should I swap bulbs between veg and bloom?

With a dual-spectrum HPS bulb (GreenPower or Grolux), no — the same lamp covers both phases. With a pure MH (Lumatek MH) or pure bloom HPS, yes: swap at the 12/12 flip. The 400W ballast accepts both technologies without modification. Many growers combine MH plus HPS to optimise each phase individually.

What extractor do I need for a 400W bulb?

A 400 to 600 m³/h extractor is sufficient for a standard 100×100×200 cm tent with a 400W bulb. Pick the upper end (600 m³/h) if you are adding a carbon filter, which reduces effective airflow by roughly 25 to 30%.

How long does a 400W bulb last?

HPS 400W bulbs have a rated lifespan of 24,000 to 28,000 hours depending on the model. Replace them every 12 to 18 months of active use — lumen flux drops 15-20% after this period, reducing yields without clear visual signs of degradation.

Order your 400W bulb from Plant & Flower and enjoy fast, discreet delivery anywhere in Belgium.