Bloom Size Plants from Seedlings

[GardenTheater]

It seems like growing bloom size orchids from seedling plants is like gambling...even when you get them from a respected grower. How many seedlings do you grow before you get something a big box store would sell? How many do you grow to get a show quality plant? Is it roughly 50, 100 or 1000 seedlings? I have Potinaras grown from seed by a respected grower and am curious about the "odds" of getting a good looking bloom.