Steve,

I agree with the 12 month replacement cycle. When I grew under lights I ran
my bulbs for 18 months or so and then replaced them all at once. I could
really tell the difference when the new bulbs were replaced.

If you wait for these things to burn out you will be wasting energy and not
getting the full benefit for your plants.

Good growing,
Gene


"Dewitt" wrote in message
...
On Thu, 11 Sep 2003 00:57:13 GMT, Steve wrote:

This week, all the plants came in. About the 2nd day, I realized the
plants didn't look yellow now. Things looked about the same as the MH
only fixture. I peered under the hood and found the HPS bulb still
working but glowing a deep orange that wasn't very bright.
Is this how they die of old age? Don't even tell me the ballast is going
bad!

MH and HPS bulbs lose intensity over time and should be replaced every
12 - 18 months. It's hard to see by eye, but if you check the
intensity with a light meter when the bulb is new and then after 12
months, you will see quite a drop.

deg