My go-to source is Orchidwiz. Unfortunately the author is retiring, and won't be adding to it or selling it after the end of the year. However, it will continue to work as long as Microsoft continues to support the underlying software. So far so good... The main loss will be that new hybrid registrations won't be captured. But for those, OrchidRoots is a great resource. But what Orchidwiz has going for it, especially, is a large collection of species culture sheets, originally compiled by Charles and Marg Baker. With the information contained in those, OW can "calculate" the culture needed for hybrids. It's on the pricey side (but now is being offered at a nice discount), but if you want a really comprehensive reference, grab it now while you can.
orchidwiz.com .