I have a purple light tube that I pulled out of storage this Winter.

I used it for a few days and then stopped as it was burning the seedling's leaves.

I don't think elevated UV is much good for plants. Maybe UVB would be better, I don't know.

You could stick a houseplant in there with Mr. Iguana and see if the leaves sunburn.

Yes, be careful. The UV might have dropped by half, but it still might be a bit harsh for most houseplants. This bulb has a very high UV output. Maybe it would be nice for colouring up some desert succulents :)

A second thing to consider is that the efficiency will have dropped. The bulb might only be putting out half the light that a new cool white tube puts out and still using the same electricity. You would save yourself money by throwing out the reptile bulb and buying a new tube that is still running efficiently.

Thanks for the responses. Jkirk unfortunatly i cant put a plant in with him, cause most houseplants would not be ok for him to eat. And if its green he will eat it. LOL Shrubs thanks for the info on the lights. Im wondering i do have a decent sized cactus, perhaps would these be ok for that?
Just hate throwing away bulbs that cost $20 dollars. LOL But from what i have seen the grow lights are a bit more resonable than reptile lights so probably will go with one of those. Dont want to take a chance at frying my plants. Thanks again for your help. Tami