Thank you Isaac for the article. I am sorry I was not clearer in my post. The article states that maximum root growth occurs at temps between 72 and 81F although I recall that citrus roots function properly down to 57F. So, for my 1 – 3 year seedlings, I would ideally want to maintain temps between 72 and 81F for maximum growth, presumably day and night. However, I believe my older trees require a cold period to induce fruit set. If so, what are the day and night temperature requirements and the duration of these temperatures?