I am having a problem to find out a proper way to measure the growth of mustard when there are so many plants and leaves to do that. I heard that I should choose and measure the longest and widest leaf of each mustard, and count how many leaf. However when I looked up to check that information, I couldn't find the article saying to choose the longest and widest leaf of each plant. Some journals show that they chose randomly but some didn't include that point.
Could anyone help me to find any reference says in detail about the method to measure plant growth? I mean the non destructive way because I cultivate them in pots.