Tent sizes veg and flower

OK so i have a question before i start ordering stuff.

Currently i have a 1200x1200mm tent, and the intention was to use this as a veg tent and get a larger tent for flowering. However, you dont get to see how bloody huge 1200x1200 is until the monster is set up in your room. It hasnt left much room for another (much larger) tent.

So my question is, how much more room do i need during the flowering stage compared to the veg stage. If i fill a 1200x1200mm tent with vegging plants, will a 1500x1500mm tent cope with them while flowering? Or do they grow massively bigger? I want to cycle them so they vary in size so i can get a crop every 2 weeks (3 sets of 2 weeks) so they wont all be full size, but still.

Could you guys give me some advice? Maybe some horror stories on plants growing a little bigger than expected?

Also i should mention the veg tent (1200x1200) will have a mother in there constantly for clones.

Oh, and it is Super Iced Grapefruit, which is apparently a heavy yielder. I suppose that makes a difference =)

Umm...it's hard to say because plant sizes vary. One guy's mother plants will be huge while another guy bonsais them. Some growers grow male plants that need to be removed and some growers have a seperate area for clones/seedlings. Basically I think a veg area should be around 1/3 to 1/2 the size of the flowering room but you can make due with less.

OUCH! So if i use the 1200x1200 as a veg room, i am looking at 1200x12400 at least for flower? I dont have the room for that =(

An option is to get a 900x900 tent and use that as a veg tent, which should house a mother and vegging plants happily...but god damn i need a bigger house!

you could use a smaller veg tent if you dont keep a mother going, i dont have a mother i just keep taking clones off clones....

True, but i do like the idea of having a true mother for all the plants, get her nice and big and then flower her when i decide it time to change strains.