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How To Make A Metal Halide / HPS Grow Light

grow light     metal halide grow light

So You Want a Cheap HID Grow Light Do You?

I was using CFL Grow lights for a few years and wanted to step up my growing capability but as I looked into HID grow lights I found out that they are not cheap.  I read on a gardening forum that somebody had used warehouse lighting as a grow light.  The light bulb went off in my head and I took a look on and started searching for used warehouse lights.  I found about 3 different people selling used fixtures.  One of them had a truckload and said come on over and take your pick.  I ended up with 2 400 watt lights, bulbs included for $30 each.  Now what is most important when you are looking for used warehouse fixtures is that you want to make sure the ballast is multi-tap.  That means you can rewire it to suit the voltage available where you are going to be using the lights.

Search these terms when looking for used warehouse fixtures:

Warehouse Light

HID Light

Metal Halide

HPS Light

High Pressure Sodium

Here's an example of what it will say on the side of a multi-tap ballast:







You see this one can be switched between 120/208/240/277







Here are the videos that I created to take you step by step through the process of converting a warehouse light into a grow light.  The first video shows the basic rewiring of the ballast and will get you up and going fast.  The second video shows a modification that will allow you to separate the ballast from the light and give you more options.





At the top of this page, the photo on the left shows the metal halide fixture running a high pressure sodium bulb,  This is possible by running what is called a conversion bulb.  The one I used is by Plantmax and was under $30.

Plantmax conversion bulb

Somebody wrote to me about a fixture they bought that had an extra red wire coming from the ballast and didn't know what is was for.  Well it turned out that when he opened the ballast the red wire didn't connect to anything.  That is pictured below.

I still search craigslist every so often to see what deals are out there.  I think the cheapest lights I have come across were going for $10 each with bulbs.  Well that just about covers everything.  If you have any questions you can send me an email and I'll be happy to help you outHappy indoor growing!



That bulb is not real grow light

SleestaksRule's picture

But it works great for growing plants.  It doesn't say "grow light" on it.

It works but not the most effective. Real grow light measured by PAR, contain 2 times more red light than those street light. Why I say that one is not real?because the burner is thin and long, real one is using thick and short burner.

GAVITA explained clearly on the differences 

and the below report also tell you most of brand are not real, except Hortilux and Ushio, but as Philips 400v 1000w 2100μmol/s standard, they are just so so.

SleestaksRule's picture

I'm looking to replace the bulbs for this winter.  Last spring I grew some hydroponic lettuce in 2 different units and each unit was under a different light.  One grew way better than the other and I assume it's due to the light's age.  When they say to replace a MH bulb after a year it's true.  I run these about 6 months a year. 

Yes, the lumens output will decrease as time goes on, according to the quality of different brand of bulb,some decrease slowly maybe you can use it for 2 years, some decrease a lot,you need to change it every year.

I will show you more documents to your email, I OEM bulbs for Sylvania.

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