Buka Boy, sorry, would be hard to make an assesment like that without a picture. But, on the up side, they may be ready to switch to flowering anyway. A month is usually long enough in veg. It depends of course on the strain and the heighth you are trying to achieve. I grow indoors and switch to 12/12 when the girls are about 12".

mark8185, a good rule of thumb is 1 gallon size per month you plan to grow. I veg for a month and flower for two, so I use a 3 gallon pot. If you are going to keep one as a mother for a longer period, I would use atleast a 5 gallon.