Metal halide and HPS differ in spectrum and therefore in where they belong in the cycle. MH, here as HPIT, is blue-rich and suits the growth phase; HPS is red-rich and works in bloom. But the most important thing on this page is not in the spectrum: these are bare lamps, and a bare lamp is not yet a lighting system.
What you have to arrange yourself
A lamp from this group needs an E40 fitting with ballast and a reflector to direct the light downward. The reflectors are in this category. We do not currently stock the fitting, so that comes from elsewhere. Know it before you order, because without a fitting you have a lamp you cannot connect. You will need a hanging system too, since the assembly is too heavy for a piece of string.
The brands and their ranges
Fertraso supplies HPS at 250, 400 and 600 watts and the same three wattages as HPIT metal halide, so you can move from growth to bloom within one brand by changing only the lamp. Sylvania has the SHP-TS Growlux in the same three wattages, an HPS tuned for growing rather than for street lighting.
Heat here is not a side effect but a design fact
These lamps turn a large share of their power into heat, and that changes your whole setup. In winter it works in your favour and saves you a heater; in summer it costs you extra extraction and sometimes a larger fan than the volume alone would call for. Count that extraction into the price of this route, because that is often where the real difference with LED sits.
When this is still the right choice
HPS stays cheap to buy and delivers a lot of light per euro, and the lamp is a consumable you replace without discarding the fixture. If you already have a fitting and reflector hanging, a new lamp from this group is the cheapest way back to full output. Starting from nothing, with your electricity bill or your summer temperatures in the balance, compare against LED first.
Frequently asked questions
Does the lamp come with a fitting?
No. These are bare lamps with an E40 base. We do not stock the fitting with ballast, so that has to come from elsewhere.
MH or HPS?
MH in growth, HPS in bloom. Within Fertraso you change only the lamp to switch, because the wattages match.
How much extra extraction does this cost?
More than LED at the same wattage, because a larger share of the power comes off as heat. Size your extraction on the heat you have to remove, not on tent volume alone.
Do these lamps degrade?
Yes, they gradually lose output while still lighting normally. Replacing after a number of cycles is part of the running cost; the figure is on the product page.
