No, its not. Madkins007 had a nice article about those bulbs here on the forum a few months ago, but I can't find it now. Something about the wave length not being the same for plants that tortoises require. Anyway, plant bulbs are not useful for tortoises.
I have had luck growing plants in my indoor enclosure with my Zoomed Powersun being the only light source. Just don't put any growing plants under the light... For obvious reasons!