cannabis plants lighting

Apart from metal halide HID, this is another variety of HID called High-Pressure Sodium (HPS). These lighting systems and bulbs supply a different light spectrum for your cannabis plants.

The most efficient type of HID light is the 600-watt HPS which often produces about 90,000 initial lumens upon startup. Nearly all of the HPS bulbs used for cannabis plants are translucent and clear.

All HPS vapor lights have their unique ballast requirements to make them function. These ballasts are not compatible with Metal Halide (MH) ballasts though some types of ballasts will allow you to ‘switch’ from MH to HPS (same wattage required for both 400-watt HPS & 400-watt MH).

Purchasing ballasts that are “switchable” can save you money in comparison to purchasing two different ballast types. High-Pressure Sodium lights emit an orange-tinted glow that is similar to a harvest sun for your cannabis plants.

This color spectrum simulates the sun’s natural signals for plants to flower though some people will use Metal Halides to flower or even a combination of the two (2) light spectrums to flower plants. HPS bulbs produce a very little amount of blue light in their lighting spectrum for cannabis plants.


How HPS Produces Light

cannabis plants

High-Pressure Sodium systems produce light by passing electricity through vaporized sodium and mercury inside an arc tube. An HPS bulb is very different from Metal Halide in its physical, electrical, and color spectrum ‘characteristics’.

An electronic starter within the ballast supplies a short, high-voltage pulse to vaporize the gases in the bulb to illuminate. This can at times take up to three (3) or four (4) minutes to fully illuminate. Similar parts for the construction of Metal Halide bulbs, HPS bulbs contain a two-bulb construction with the outer bulb as the casing and the inner part of the bulb being the inner arc tube.

High-Pressure Sodium bulbs may be placed in any position without resulting in lumen loss or efficiency, unlike metal halides. HPS lights have the longest lifespan and the best lumen maintenance out of all HID bulbs for cannabis plants.

After many hours of operation, the sodium in an HPS bulb tends to ‘bleed’ out through the arc tube. With prolonged leakage, the result will end up with a change in the ratio of sodium to mercury and cause the bulb’s voltage in the arc to rise and then burn out.

1,000 watts HPS bulbs usually have a lifespan of about 24,000 hours (5 years of 12/12 day/night cycle). Growers will replace HPS bulbs after 18 – 24 months of growing to keep the lumen output for the garden high to maintain productivity.

Metal Halide Lighting

marijuana plants

As with Metal Halide HID systems, HPS bulbs require a specific ballast type to operate. Each of these ballasts needs to have the same wattage as the hood and bulb to operate properly.

You can purchase complete HID lighting system kits rather than purchasing components separately. When you purchase a lighting kit the system will cost less though you will not always find exactly what type you want (bulb, hood, and ballast) within a kit and should purchase separately.

High-Pressure Sodium bulbs are used for industrial, residential, and horticultural lighting. HPS can commonly be found in hardware or building stores, but most hardware or building stores will only carry 250- or 400-watt bulbs.

If you want other bulb sizes, you will have to go to a growing store or order online to have them shipped. HPS bulbs are fairly inexpensive to purchase and no matter what type of HPS bulb you use it will grow cannabis plants.

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