How long is the waiting period for contamination?

[wetfeet101b]

I prepared 10 small mother flasks last saturday and I am letting them sit in the shade and room temperature to wait if there is any contamination in the flasks.
So far I have not seen any changes in the color/consistency of the sowing medium but it may be too early to tell if I'm in the clear.

How long would it be before any contamination manifests itself? a few days? weeks?
What is the incubation period for the typical molds that would be encountered in such flasks prepared in the home/kitchen environment?

[margo]

John, from what I learned about 5 days to a week should be enough. If there is something you should be able to see it within 3 days.

[Gin]

I let mine set for almost 2 weeks before sowing the seeds but think in 10 any contamination should show up .. Good luck with them .. Gin

[wetfeet101b]

Another question:

Should the jars be airtight throughout the entire process? or should they be allowed to vent somehow once the seeds are sowed?

[margo]

Sorry, I can't give any advise about this! I wish I could, but ... one of my flasks contaminated 3 days after seed sowing... the second one I just noticed yesterday- contaminated one month after seed sowing... and I only have one more that looks nice and clean... yep clean... nothing is growing in it.

[cindiras]

I would think you would want to seal the lid after sowing seeds. The flask will provide an incubater type environment. Venting would allow the possibility of contamination. Seal the injection hole with a silicon caulk.

[Brutal_Dreamer]

I have seen some flasks with a small, dense cotton plug in the lid. Not sure how it works, but it would seem to let pressure out and use the cotton as a filter. Anyone know what that is for?

Cheers,
BD

[John D.]

I usually wait at least a week before sowing. The flask needs to be sealed enough that any air exchange in or out is filtered so as to exclude mold spores or bacteria. That is what the cotton plug is for. It needs to be sterile (with the flask) and tight enough that any spores don't make it into the flask with air exchange. The air exchange takes place from osmosis (if the plants use CO2 and produce O2 the molecular motion causes equalization of concentration) minor way and the daily temperature flucuations cause pressure changes which moves air into or out of the flask major way. This is where the major moisture loss in a vented flask comes from over time. Germinating seed gets its carbon from the media not the atmosphere so mother flasks are often sealed. Some folks do not vent replates and don't have any issues as long as the plants are not crowded.

[Brutal_Dreamer]

Thanks, John D.

Cheers,
BD

[wetfeet101b]

Germinating seed gets its carbon from the media not the atmosphere...

This has me concerned. I did not add any supplemental carbon in my mother flasks' sowing medium.
I wonder if the home made mix that I made has sufficient trace carbons to supply the needs of the seeds.