seed starting, need information about grow light bulbs

I got my seed starting plant stand out of the shed and am working on getting the fluorescent tubes working. Do I need all new bulbs or are the ones I have, (several years old) good enough? Do they all have to be "plant light" full spectrum bulbs or a mix of cool and hot?
Thanks.

I use T12 cool white 48" fluorescent tubes which I purchase in boxes of ten from Lowe's.

Fluorescent tubes dim with age. They are brighter in the center than they are on the ends.

If your seedlings do well under the tubes you have, there is no need to replace them.

Typically you replace them once a year. They darken on the ends of the tubes over time. They are cheap enough, just use normal tubes. No "special" tubes are needed!

Thanks, I picked up some today and will keep a few of the older ones too.

Rose,

I use my florescent tubes for at least two years before replacing. It's worked out that I end up replacing about half the tubes in the set every year. That means that two of four bulbs is new every year.

David

Sounds like a good plan. Thanks.