Grows Per Bulb

I'm on my third grow with a 400 MH conversion changing after about five weeks to a 400 HPS. I realize that they lose power over time, but how many grows do people do generally before replacing?

I change mine every 3-4 grows. They can go for longer but you will start to loose the power of the light lummens.

Anyone else care to respond? The MH bulb is a Grow Power, and the HPS is in an HTG package.

timeout said:

Anyone else care to respond? The MH bulb is a Grow Power, and the HPS is in an HTG package.

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You can use them usually for about a year of normal useage. So about 3-4 grows. You want to replace them before they burn out because the lumen decrease on HPS and MH bulbs is pretty dramatic.

i normally change mine every 6months, 2-3 grows hid bulbs dont last that long

every 2-3 grows depending on how long you use it or if you only veg for a month then you got 6 months of grow per bulb and then for flowering you only got 3 grows because its average 2 moths flowering and veg you got 6 grows with it if average 1 month veg. so mh (6 grows which is 6 months ) hps(flowering 2 months flower time so 3 grows)

Ask this question to 10 growers and you are bound to get at least 6 different answers!

In this case the only opinion that makes any difference is your's! When the yield drops below "acceptable" - replace the bulb!

You have to make that choice! You draw the line, what is "acceptable" to you? Some would say "When the yield is down by 1/4 to 1/3", some would say "When the yield is down by 1/2".

I say, as long as the bulb produces a reasonable yield, keep it - when it's no longer "acceptable", replace it. That's up to you!

Wise words. Thanks man.

at 50 dollars a bulb some 80,when your los ing a 1/4 o your yield,why would you find that exceptable ,a 1/4 of your yield under a 600 is 2 oz or more,why would you except losing 400 dollars over $60.3 grows is good enough.

Thanks for the responses. As my present grow is only my third, I don't have much of a baseline for determining my "acceptable" yield. Suffice it to say that I've made the full range of noob mistakes. That said, and having flowered 10 weeks or so for both the first and second times, and wanting to switch to a Hort. next time (since the $500 per ounce I've invested so far hasn't deterred me), I'll plan on swapping the old out.

Does anyone use a light meter of some sort to mark the decrease in output?