GMSgrowsanswered grow question 3 years ago Older leaves do whither and die. They will help supply other parts of your plant with nutrition. It sucks the life out of them so that other leaves may thrive. Be careful on using full strength nutes. Over feeding is very detrimental to your plants and if they do get overfed your nuggies and overall harvest will suffer. If your following the fert label for feeding, just go half. Cheers