Taiji
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Location: Gardening in western U.P. of MI. 46+ N. lat. elev 1540. zone 3

Light bulbs probably too old.

This years tomato seedlings seem longer and spindlier than usual. Did everything exactly the same as in previous years; T 12 bulbs, 6700 (I think) K; but seedlings seemed to be reaching for the light though in some cases light is touching the plant.

Then realized that this is probably the 4th year for the same bulbs. I changed them out, and the seedlings seem to be thickening up nicely, and are finally getting their true leaves. Now are ready for up potting. :-()

I think it was the old lights. Is 3 or 4 years too long?

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applestar
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Location: Zone 6, NJ (3/M)4/E ~ 10/M

Re: Light bulbs probably too old.

I suppose it depends on how you use them, but I use my lights 7 months of the year, so only get a couple of years out of them. T5's will actually burn out, T8's get super dark on the ends with visible dark bands, T12's will keep going until they start to flicker but will also darken on the ends of the tubes. Since T12's are not as bright to begin with (compared to T8 and T5), any % reduction in brightness is probably significant.
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imafan26
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Re: Light bulbs probably too old.

What will you do when the flourescents get scarcer? Most of the new lights are LED which are brighter but don't have the spectrum for grow lights unless you buy grow lights.
Happy gardening in Hawaii. Gardens are where people grow.

Taiji
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Location: Gardening in western U.P. of MI. 46+ N. lat. elev 1540. zone 3

Re: Light bulbs probably too old.

imafan26 wrote:What will you do when the flourescents get scarcer? Most of the new lights are LED which are brighter but don't have the spectrum for grow lights unless you buy grow lights.
Yes, I was thinking about that too. They still have them at WM and HD so I was thinking if I wanna continue with this T 12 thing I should probably go and buy a bunch in bulk. I wonder if they start to go bad just sitting around?

Hours per day I'm using the lights are around 14 to 16 hrs. As they start grow dim maybe one could increase the number of hours, but maybe that would mess up the plants' bio rhythms?

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applestar
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Re: Light bulbs probably too old.

T8 and T5 fixtures prices are coming down thanks to the upsurge in the LEDs. I'm also starting to see aquarium hobbyists switching over to the LED's and offering their lights up for cheap. Those short ones are great for shorter shelving units and odd nooks and crannies. I think we can enjoy the limbo state for a little while before the fluorescents start to disappear.

Hopefully, in the meanwhile, they will continue to improve the LED technology and available options, and prices will come down for them also.

I heard that T12's are going to be obsoleted ...very soon... was it this year? 2020? If you switch up to 4 ft. T8 shoplights which are price-wise basically at where the T12's used to be a couple of years ago, you can get LED bulbs that are designed to fit the T8 fixtures. They used to be kludgy but are starting to look more like something an average consumer can use. I'm thinking of trying them.
Learning never ends because we can share what we've learned. And in sharing our collective experiences, we gain deeper understanding of what we learned.

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