A vegetation cycle can be as short as the plant genetics will let it be. They recomend starting extremely tall with a long flowering period sativas at 12 on 12 off so they will start to flower as soon as it will. An indica would grow extremely short and probably not have a good thick stalk or root system. THe buds will small. I have grown a plant with no care in a 5 gallon bucket which flowered immediatly and had a fully matured cola with a bud the size of a pencil eraser.