Flask Shelf life
 

Let's assume that I am going to be able to flask correctly in a contaminant free environment. I leave the flasks in the fridge for five days to check for contamination & spore formation etc.. My question is how long can a contaminant free flask stay that way before sowing seeds into it?:evil:

From what I have read, the longer it goes without growing anything, the more certain you can be that it is contaminant free. But the outside of the flask would need to be cleaned/sterilized before working with it.

They are useable for quite awhile, as the plants are growing in them for 6+months anyway. But I'd try to use them in 1-3 months are making them, with 3 being a stretch. Also, if you want to check for contaminants, you probably shouldn't test in a fridge. Put it in your grow space. Then you'll find out if you were really contaminant free, and this is where they'll be placed anyway to grow plantlets.

I would also leave the flasks outside the fridge, you'll spot any contamination more quickly. Why did you put them there?

Since I have never germinated orchid seeds but I have germinated mushroom spores, allow me to ask some silly questions. These are agar flasks right? Weren't they prepared with a pressure cooker? Why would newly prepared flasks have any viable contaminants?

Totally reasonable question David, but it depends on if someone used a pressure cooker (some people boil in a microwave, or use Bleach with some success). Also, another key factor is making sure they stay contaminant free following sowing, though that may be beyond the scope of OP and your post.