Outdoor Plants

They will definitely get bigger, its just a matter of how much bigger they will get.

 

Depending on the strain, mostly sativa dom. strains, can easily stretch and triple in size once they start flowering. For example I am currently growing Tga's Quantum Kush and it says on his website that it can easily triple in size once it starts flowering. But you have to take into account the amount of room the roots have to grow as well because the bigger the roots the bigger the shoots!!! Plants in the ground will easily triple in size once they start flowering.

 

They won't tripple in size during flower. That is a general rule for indoor. My plants are 8ft tall at the start of flower. They will be 24 ft tall when flower is done. To funny.
They will stretch about a foot or 2 right before flower.

 

 That is not always true though Danko, it depends on the strain you are growing. But very true general rule for indoors, they will not triple in size. I believe the original poster was asking about outdoor plants so it is very possible they could triple in size during flowering... Although not if your plant is already 8 ft tall..Obviously

 

Yea it's only true for small plants. The larger the plant the less it grows in flowering. A 8 ft plant should only grow a few feet.

 

My plants have just started flowering. They were 5 ft tall a week ago and their about 6 ft tall now. They may end up about 7 ft tall at the end, maybe a smidge taller. I only have 20 gal pots which is a major limiting factor.