GrowCNanswered grow question 3 years ago When to switch totally depends on you. I've done a veg as short as 4 weeks though 6 is more common for me. I do not like plants growing against the sides of the tent so I veg when the plant is about 1/2 the size I want. I don't mind if the plant occasionally touches the side of the tent but I don't want the plants touching the walls all around. I want space to allow airflow to the bottom of the plant. Plus, big sticky buds rubbing on the side of your tent make the tent sticky.