HID Bulbs

Marijuana Horticulture

by Jorge Cervantes

Many new HID bulbs have been developed in the last few years. The most notable have been the 430-watt HP sodium, pulse start metal halides, the AgroSun, SunMaster PAR bulbs, and the 1100-watt metal halide. These HID bulbs are also available with many different outer envelopes, so bulbs can fit into more confining reflective hoods.

High intensity discharge bulbs are rated by wattage and by the size of the outer envelope or bulb. HID bulbs come in different shapes and sizes. Below each bulb are the numbers industry uses to define their shape and size.

In general, HID bulbs are designed to be tough and durable. New bulbs are tougher than used bulbs. Once the bulb has been used for a few hours, the arc tube blackens, and the internal parts become somewhat brittle. After a bulb has been used several hundred hours, a good bump will substantially shorten its life and lessen luminescence.

Never remove a warm lamp. Heat expands the metal mogul base within the socket. A hot bulb is more difficult to remove, and it must be forced. Special electrical grease is available to lubricate sockets (Vaseline works too). Lightly smear a dash of lubricant around the mogul socket base to facilitate bulb insertion and extraction.

Always keep the bulb clean. Wait for it to cool before wiping it off with a clean cloth every two to four weeks. Dirt will lower lumen output substantially. Bulbs get covered with insect spray and salty water vapor residues. This dirt dulls lamp brilliance just as clouds dull natural sunlight.

Hands off bulbs! Touching bulbs leaves them with your hands oily residue. The residue weakens the bulb when it is baked onto it. Most growers clean bulbs with Windex or rubbing alcohol and use clean cloth to remove filth and grime, but Hortilux Lighting advises cleaning bulbs with a clean cloth only.

Lumen output diminishes over time. As the bulb loses brilliance, it generates less heat and can be moved closer to the garden. This is not an excuse to use old bulbs; it is always better to use newer bulbs. However, it is a way t a few more months out of an otherwise worthless bulb.

Write down the day, month, and year you start using a bulb so you can better calculate when to replace it for best results. Replace metal halides after 12 months of operation and HP sodium bulbs after 18 months. Many growers replace them sooner. Always keep a spare bulb in its original box available to replace old bulbs. You can go blind staring at a dim bulb trying to decide when to replace it. Remember, your pupils pen and close to compensate for different light levels. one way to determine when to replace a bulb is to examine the arc tube. When the arc tube is very cloudy or very blackened, it is most likely time to replace it.