Answer: While it may seem that much of the information is contradictory, in many cases different methods do work and it is a matter of trial and error to discover which of them work best for you and your particular greenhouse set-up. In any case, gardeners have a saying that "Plants never read the book!" and so many times that really does seem to be true. This website includes information from a large number of academic institutions http://www.hcs.ohio-state.edu/factsheet.html and can be searched quite easily. Perhaps you will find it helpful.
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