growth during flowering

i have a plant thats about 1 foot and a half tall i the forst week of flowering. i heard that plants double in size during flowering will it be 3 feet in the next 7 weeks?

Some do thats average I would say under normal conditions

A female will typically do some "rapid growth" when you first cut back the light, but before it starts flowering. This phase can cause growth to get outta hand if you don't watch it, and can certainly give 3x the pre-flower height. After actual flowering starts, the added height is more of bud production than veggie growth. #x is possible there, but I find 2x or less to be more typical.

thanks alot for the help, i also heard about cutting the leaves a day or two befor harvesting. have you heard anything about this?

I did that one some. It just gives more light to the others you are shoving under light in my opinion. It may slow transpiration down by reducing the amount of stoma allowing the plant to use the nutes stored in the viens of the plant giving better flavor. I never kept track of the trimmed ones from the non trimmed ones so it is hard to say. I used a very low ppm also.