Orchids have a reputation as the divas of the plant world: fussy, difficult-to-grow plants that - on top of all that - are prohibitively expensive. But there are plenty of orchids that anyone can grow. Orchids are no more difficult than familiar houseplants such as the African violet, and can be made to thrive and bloom in average indoor conditions. You just need to know what makes them happy. ''Bloom-Again Orchids'' highlights the easiest, most fuss free varieties and includes invaluable tips on where to buy orchids and how to keep them in bloom. Each of the fifty profiles focuses on a commonly available orchid variety and includes a description, photograph, chart of basic growing requirements, and a handy twelve-point checklist. So if you've always been intrigued by orchids but were nervous about caring for them, put your worries aside. ''Bloom-Again Orchids'' will turn you from a would-be orchid fan into the proud owner of healthy plants that will bloom year after year.