say your growing weed under a 400w HPS and you keep 1 plant never chop it down just kept looking after it how long would it live for has any1 actually tried this?????
depends on the strain, but yes, if it isnt an auto flowering strain you could keep that strain alive forever if you wish. simply take clones and swap out mothers every few months. there are quite a few people on here who keep mothers. remember you're going to want to keep your mother plants all it takes to keep one alive is a few Cfl's and remember to feed her every once in awhile.
cannabis is an annual plant, in nature they would sprout in spring and die in october/ november. the average lifespan for a plant grown for the purpose of harvesting and smoking usually lives 4-5 months before they get the axe... but like i said, if you keep her under 24hrs of minimal light she wont flower, meaning she wont "die"