Quote Originally Posted by profitprophet
How long can I allow the plants to go completely vegetative (24 hr light) and stay healthy?
Short answer? Forever. Long answer? For about 4-8 months before they become too large to deal with (assuming no FIMing, etc), get sick from something or another, or just die off. You can, however, veg them for a very long time, switch to flower 12/12, then switch back to veg after a harvest or halfway through a harvest (leaving the lower branches alone). This is how to perpetuate a single plant. You can also alternate from 24 solid to 18/6 back and forth and veg for an extremely long time. I have known of plants that stretched several meters this way.