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Image from: growingmagazine.com

                        Image: growingmagazine.com

What are HID grow lights?

If they aren't already, grow lights should be at the top of your list of hydroponic supplies. High intensity discharge, or HID, lights are a favorite among growers looking for a cost effective way to provide light to their grows. They are pretty similar to household bulbs, but main differences being HID lights are a lot bigger, and instead of using a single metal filament to light the gas like in a household bulb, the HID light use two electrodes that transfer currents to light the gas – which equals more light.
There are a lot of HID lights on the market but two types we would recommend for growing will be metal halide (MH) and high pressure sodium (HPS). Because of the different gas produced in each, these two types of lights produce different color spectrums, which are perfect for simulating the different seasons in nature. Here's an another article for further information on HID grow lights.

 

Metal Halide and High Pressure Sodium 

MH bulbs are great for plants in their vegetative stage due to the blue color the light produces. These bulbs will help you achieve the leafy growth at the beginning of the plants life which is super important to get right if you want to maximize the yield.

HPS bulbs are more suited to the flowering stage of your plants life as the light gives off a red and orange tinge and activates the hormones that can actually increase the number of flowers.

Your local hydroponics store will stock both HPS and MH lights. 

Double ended vs Single lights

Since they came onto the market a few years ago, double ended lights have been receiving rave reviews from growers. In side by side comparisons to single ended lights, double ended lights have been seen to maximize yield. This is because the stability from double ended bulbs allows an increased intensity in the light emitted.  Another nice advantage of the double ended is that they degrade at a much slower rate than the single ended, meaning they need replaced a lot less frequently.  

Double Ended (DE) and Single Ended refers to the manner in which the lamps are connected to the socket system.  Traditional Single Ended bulbs screwed into a socket, a larger version of what you have at home.  While Double Ended, pictured below, have a wire protruding from the bulb on both ends.  The bulb is clamped into place on both ends.  This ensures a strong electrical connection to the double ended socket.  Single ended bulbs tend to sag in the reflector, rarely operating in the ideal position for the reflector.  Double Ended bulbs remain fixed in the place designed for ideal light distribution.

 

Double Ended HPS Light

 Double Ended HID Bulb

 

Can I use one type of light for the duration of my grow?

Technically you can, but we wouldn’t really recommend it. The results won’t be as impressive as if you had used specific lights at each major stage of growth. If you really needed to choose a single light type, HPS would be slightly more suited for the duration of your grow. 

Where should I hang my lights?

You should hang your lights according to the wattage of your bulbs. The higher the wattage, the further away the lights should be away from your plants. We have created a quick reference guide on distance from plant to light and also the area of coverage from each watt. Please keep in mind this is a rough guide and you should keep an eye on you grow to find out exactly what works from your own plants. This guide has been created assuming that the bulbs are the plants only source of light (indoors with no sunlight). You can come into our hydroponic store to see what the lights look like in person.

 

HPS

Watts

Height Above Plants

Grow Size

250

10’’-20’’

2’x2’

400

15’’-24’’

3’x3’

600

20’’-30’’

4’x4’

1000

24’’-36’’

5’x5’

MH

Watts

Height Above Plants

Grow Size

250

10’’-20’’

2’x2’

400

15’’-24’’

3’x3’

1000

24’’-36’’

5’x5’

 

What are ballasts?

Ballasts are used for both HPS and MH bulbs. They used to regulate the electricity in the bulb to create a smooth flow of electricity so ultimately they control the brightness of the light.

Ultra high frequency ballasts for double ended bulbs are a popular choice because of their ability to deliver light consistently at a very high frequency, meaning a constant stream of lights to your plants.

Ultra High Frequency Ballast

 Ultra High Frequency Ballast

Overall...

So, in a short summary we would highly recommend that you start out with using MH bulbs for veg, then transition to using HPS for bloom. We find ultra high frequency digital ballasts the most effective for maximizing your lights. While the optimum wattage for grows really depends on the size of your individual garden space. We have a large selection of lights both in store and online which you can check out here: http://pchydro.com/pages/lights .

We understand lighting can be a bit of a headache for those of you just starting out, so if you have any further questions come into your local hydroponics store here in Culver City and we will be happy to answer!