Flasking in pf tek brown rice flower vermiculite cakes

[Kingjoshua]

I was just wondering if anyone has tried using pf tek to flask orchid seeds. I have never had any luck with agar as I always have had contamination in my flasks. Pf tek is usually use for growing mushrooms. It is made with two parts vermiculite one part brown rice flower and one part water. It is then placed in jars and sterilized in pressure cooker before being inoculated with mushroom spores. As I have not had any luck with agar I was wondering if this would be worth giving a try.

[estación seca]

Welcome to the Orchid Board!

I haven't tried it. Contamination of the medium does not depend on the medium. It depends on your sterile technique. If your agar flasks become contaminated, your Pf tek flasks will become contaminated, unless you improve your sterile technique.

Is there a community college nearby where you can take a microbiology course? Sterile technique is hard to learn without a teacher there to correct you.

[PaphMadMan]

Contamination is mostly dependent on sterilization procedures and sterile technique, though some materials are just harder to get sterile than others. Large volumes of liquid or some granular porous materials may be more difficult. If you have had success with pf tek and mushroom cultures it might be worth a try, but keep in mind that mushroom mycelium is much faster and more aggressive in colonizing the medium and is probably directly inhibitory to many possible contaminating organisms. "Sterile enough" may be very different under those circumstances. Also, adding the sugars and nutrients normal in orchid media might let contaminating organisms grow much faster and become a problem.

Orchid seeds have certainly been successfully grown on materials other than agar though I am not aware of this particular medium. Both the vermiculite and the rice flour may contain substances that could directly inhibit orchid seed, interfere with pH, precipitate nutrients. You may have some experimenting to do to be successful.

Reviewing your knowledge of sterile technique is a good place to start. And have you tried letting freshly made sterile media remain unused for several weeks to see if there is contamination before sowing? That would narrow down whether the problem is in sterilization or in technique or conditions when sowing seed.