Aqueminianswered grow question 3 years ago It's best to assume the plant will double in height. So get it half the size you want and flip to flowering. Some plants can triple in size when the stretch finishes, some don't stretch at all. Its Dependent on strain, it's good to grow a strain a few times so you can learn the Genetics and Master growing that specific strain. I always try to get my plants half the size I want before flowering.