My brother lives in Thailand and he told me of a market that sells certain days of the week....I wonder if this is it? He said the orchids are amazing and now I can agree with him. Amazing!
This is the main venue for orchids sales out of a market in Bangkok as far as I know. The sell a lot of hybrids and species. A number sell flasks at the markets too.
It is very easy to get to. Just ask the taxi to take you to Jatujak market or the Weekend Markets - they should not it. The orchid market I mentioned in across the road opposite the Royal food market. Locals should be able to direct you if you are in town. If I can find a map, I will post it.
Jatujak is the only market I know of that runs Wed/Thurs.