Flasking questions

[greengarden]

If you sterilise the seed with 3% peroxide instead of bleach you won't need to wash it off the seed. Peroxide degrades in light so once you have innoculated the plate just sit it in the light for a little while before putting it away and the peroxide will be gone, it will also help sterilise the surface of the agar further too.

[zxyqu]

Nope the unopened just wont be sterile, so you'll need to pressure cook that for sure I'd imagine. Maybe you could find some sterile water somewhere, not sure. That scale balance you mentioned should work just fine, and the glove box sounds nice.
I'd stick to just about everything mentioned in the youtube video for dry seed sterilization, and it should work well. Just dont oversterilize the seed in bleach. Time is critical.

[The Orchid Boy]

I know that Phyto Tech Labs has sterilized water. How would you pressure cook the water? In jars with the lid cracked at a certain pressure? Could I do it in the microwave? To mix the media do you need sterile water or distilled? When rinsing the seeds I use sterilized water right? And is the 3% peroxide already diluted and is it easy to find? Thanks!

[greengarden]

Sorry I meant after pressure cooking, didn't mean that it was the be all and end all. The method I'm starting to use now is to put a hole in the plastic jar cap and fill the hole with silicone. Put the agar in and pressure cook/microwave to sterilise. Then mix the orchid seed with peroxide insde the syringe and use a large gauge sterile needle to innoculate the agar through the silicone on top of the lid. This way you don' even have to open the lid after doing the pressure cooker No need for a clean box or any of that(which is what he used to use before he started doing it this way)

This is a method a guy I know has been using with great success and I'm now convinced to give it a go as it looks so much easier! I need to get some more agar and jars with plastic lids and I'll take a photo sequence when I do my first lot.

[The Orchid Boy]

Do you have to seal the hole in the silicone? When you replate you would have to use a clean box though right?

[greengarden]

The hole in the silicone is self sealing so when you pull out the needle it closes back over fine. He sows lightly and has found most things go all the way through without a replate, sometimes it is necessary though yes.

[The Orchid Boy]

I might have to try a few flasks that way.

[The Orchid Boy]

The P668 media that can be used for cattleyas and paphiopedilums on the chart for reccomended media has a little 1 or 2 by it like P668^1 or P668^2. What does this mean?

Greengarden, could you explain a little more about the peroxide? Do you have to dilute it? What does the 3% mean? The method with a hole sealed with silicone, how do you know if you're sowing lightly enough? And what media do you use if you never replate?

[greengarden]

I'm in Aus so I don't have the same branded media available to me but the one I'm getting is a fairly general purpose one suited to sowing and replating so the plants can stay in there essentially as long as the nutrients last if that makes sense.

The peroxide for me is just bought directly from the pharmacy or supermarket and comes as a standard 3% dilution, it would depend what you have available there, it is not diluted any more than this.

Really it's just a matter of getting a feel for things, you'll see pretty quickly if you are oversowing but because it is through a syringe you can be fairly careful.

[Bloomin_Aussie]

P668 is a general sow and replate media. I believe it is sold as a powder that does not contain agar so that it can be diluted as required. The notations may have something to do with that. Could you link us to the reference sheet you are referring to?

In terms of disinfecting with hydrogen peroxide, the times required will vary depending on a few things. I suggest you do several batches using different disinfection times to see what gives the best results. Generally a "pharmacy strength" hydrogen peroxide solution will work more slowly than a "houshold strength" bleach. It may take an hour or so to kill contaminants on dry seed. If you soak the seed overnight to thoroughly wet it (can add a little dish detergent as a wetting agent too), you'll find the disinfection process will be more effective and require less time.