Bulb HPS/MH 400 Watt

There is a sweet spot in indoor lighting where power meets practicality, and the 400 Watt sits right in the centre of it. Find proven 400W HPS and MH bulbs in our range, including the Philips GreenPower 400W, the Lumatek HPS 400W and the Superplant Super Red 400W.

400 Watt HPS and MH bulbs: the balanced choice for indoor growers

Ask experienced cultivators which wattage they would recommend to a friend, and many will point to the 400W. It generates roughly 50,000 lumens, enough to comfortably illuminate 1 to 1.5 square meters without turning your tent into a sauna. That makes it the natural fit for standard 100×100 cm to 120×120 cm grow tents favoured by hobbyists and semi-professional growers alike.

Vegetative growth and flowering under 400W

During veg, a Lumatek MH 400W produces a crisp blue-white spectrum that builds thick stems, broad leaves and tight internodal spacing. This sturdy framework is essential since the branches need to support heavy flowers later. When you flip to bloom, the Sylvania Grolux 400W or the Osram NAV-T Super 400W deliver the warm spectrum that triggers prolific flower production.

Key advantages of the 400W category

• Deeper canopy penetration: noticeably better than 250W, allowing lower buds to develop properly.
• Manageable heat: a mid-range extractor at 400 to 600 m³/h typically keeps temperatures in check.
• Substrate flexibility: performs equally well with soil, coco and hydro setups.
• Cost efficiency: excellent balance between purchase price, running costs and harvest weight.

Cultivation techniques that shine at 400W

The increased intensity compared to 250W makes training techniques especially rewarding. SCROG creates a uniform canopy at the optimal distance from your lamp. LST increases the number of flowering sites without plant stress. Targeted defoliation improves airflow and lets light reach deeper plant layers. Pair these techniques with a quality reflector and a properly matched 400W ballast for best results.

Explore our 400W lighting kits for a turnkey solution, or the HPS-MH grow packs that include tent and ventilation. Return to the main HPS/MH bulb category for a full overview. Fast, discreet delivery across Belgium.