depends on what you're growing, what its natural habitat is, and what the intent is of 'intensifying' the growing process...

but no, while it's POSSIBLE to grow plants under 24 hour lighting condition- it has a very similar effect on them that it has on us. it shortens their lifespan, and can create stress in them that can cause anything from suseptibility to viruses to nervous breakdowns.

the growth hormones are interesting to experiment with, but their effects are rarely attractive- they tend to increase the internode length more than leave size or distribution, creating attenuated giants.

I went back to super rich soils for everything but my nasturtiums and other 'poor soil' lovers, and just let the plants be plants.

Actually, if you leave the lights on 24 hours a day, you will do so at great sacrifice to the plants. There are a myriad of plant functions that take place in the dark. Accelerated growth can be achieved by providing more fertilizers than the plant actually needs, but accelerated growth is not necessarily a good thing.

Forcing a plant to grow faster than 'normal' directs all of the energy to vegetative growth. The plant will be less able to fend off insect and disease infestation, to maintain healthy roots, to flower, and or to develop fruit.

If your plants are doing poorly, then you may want to evaluate the kind of soil you use, as well as your fertilization program.

(Rhizo- I don't think this kid is the least bit interested in cellular respiration and the oxygen cycle...and I don't think it's working on a school science project either. just a hippy's hunch- but there it is ;)

(Chinacat....you know, I had been suspicious of the exact same thing....about the same time I pushed the 'send' button! And to think I forgot to mention the rubbing alcohol soil drenches or the extra invigorating microwave treatment!)