You could use plant bulbs which produce specifically UVA light to increae the plants health. These are usually florescent bulbs that have a stong red tinge to the light. Most reptile bulbs, like the 5.0 have a blue tinge. Plants also benefit from them, but are more dependant on the redish UVA producing bulbs.
Don't forget to make sure that no UV producinv lights should pass through glass or any clear peices, as they may reflect some or all of the UV back.