It is quite possible when growing indoors to grow a plant from seed, through the vegetative cycle, flowering and harvest, and then force the plant back into the vegetative cycle to repeat the whole process!
How does this happen?
Cannabis' life is governed by the hours of light it receives, if a plant is kept under a light for around 16 or more hours per day it will stay in the vegetative cycle indefinitely, if the light hours are reduced to around 12 hours per day the plant will go into flowering mode.
If, when the flowering has finished and the crop harvested the light's are put back to 16hrs per day, the plant will be forced back into the vegetative cycle.
What do you need to do?
It is surprisingly easy...
When harvesting your plant, try to leave quite a few bud sites intact at the bottom of your main stem, (as in the picture below). The more bud sites you leave intact, the bigger and bushier the new growth will be!
Aswell as switching the light back to 18/6, 20/4, 24/0 or whatever, the plants are going to need a feed as the nutrient levels in your soil will be very low, especially if you have flushed recently ready for harvest.
If it is possible, it is a good idea to re-pot your plant into an even bigger pot with good, fresh compost. If it is not possible to re-pot because of size restrictions etc then you'll need to give your plant/soil a feed to boost the N-P-K levels. I have found that one good feed is enough until new growth is established, and then occasional half strength feeds if needed.
New Growth
With the light's back to the veg cycle and the plant fed, the plant will start to grow new shoots. Usually it takes 2 or 3 weeks before any new shoots are noticed and the growth of the new shoots can look very strange, single leaves will grow aswell as other mutant looking leaves (as seen in the pic below). This is completely normal and after a couple of weeks growth the 'proper' leaves will start to appear.
How Long Do I Veg For?
As with all Cannabis plants, the longer you keep the plant in the re-veg cycle before switching to flowering, the bigger and better your plant will eventually become. Although, for best results it is better to wait until the re-vegged plant is producing a good amount of 'proper', full leaves again before switching to the flowering cycle.
A lot of growers who re-veg claim that the harvest the 2nd time around can double and sometimes triple the amount of the first crop!
Some growers also claim that re-vegged plants are not as potent as they were the 1st time around... In my experience this is not true!
Clones
As with re-vegging whole plants, it is quite possible to re-veg a plant from a clone/cutting taken from a plant in flower. (as in the pic below).
The exact same principles apply to clones.
