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sterilizing clay pots

Discussion in 'Orchid Culture' started by cathy, Oct 29, 2014.

  1. cathy

    cathy Member

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    I am going to run my pots through my kiln. Has anyone done it and what temperature should i aim for?
     
  2. Alexey

    Alexey Well-Known Member Supporting Member

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    I am not aware about kiln features and if it has a thermostat. In general, 1 - 1,5 hour at 100 degrees C will be enough to sterilize previously used clay pots.
     
  3. Dave The Scientist

    Dave The Scientist Active Member

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    A kiln is probably overkill. An oven will do the trick just fine. 100 degrees C is probably too low though. Autoclaves run at 121- 160 degrees C depending design and that is under pressure and damp heat so it probably produces more efficient sterilization than an oven.
     
  4. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    If you have a kiln with a programer it is perfect. I use 250 F for an hour to sterilize things for the lab and it works.
     
  5. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    I checked the controller today and need to correct my statement. I use 356F for 1 hour for most things and 250F for paper towels.
     
  6. Mandy2705

    Mandy2705 Member

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    Marni and Cathy, do you guys make your own pots? I am just assuming you do, since you have kilns I wish I can make my own pots, but i would have to participate in a class and it's costs hundreds of dollars.
     
  7. Alexey

    Alexey Well-Known Member Supporting Member

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    Termin sterilization have different protocols and criteria depending on the implication. Hope we are not going to use medical for clay pots. Lab or flasking protocol would be also overkiling (it is intended to sterilize spore forming microorganisms as well). The biggest fear of orchd grower is viruses. For them soil sterilization protocol will be enough. Advising 1 - 1.5 hours at 100 degrees C, I have insured that required for that protocol temperature of the material (90 degrees) will be exceeded.
     
  8. Dave The Scientist

    Dave The Scientist Active Member

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    Thanks Alexey for that informative answer.
     
  9. Clark Thomas Riley

    Clark Thomas Riley New Member

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    I have been using terra cotta for a long, long time with great success for Sophronitis and rupiculous Laelias. I soak them in hottest tap water first, let it cool down and scrub off the old potting residue with a green scrubbing pad (NO SOAP!) for appearance. A quick rinse and into the oven they go at 500°F until they no longer steam (about 45 minutes to an hour). I turn off the oven and let them cool with the door closed. This is probably more extreme than necessary but the pots are sterile and as light as terra cotta gets. This method is helpful if you have a lot of pots to do. I typically do 30 - 40 pots at a time. NOTE: glazed terra-cotta pots often explode.
     
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  10. Dave The Scientist

    Dave The Scientist Active Member

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    Wow, that sounds intense.
     
  11. Clark Thomas Riley

    Clark Thomas Riley New Member

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    Intense, yes. One of those "learning experiences." For normal pots, it's amazingly efficient and reliable.
     
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  12. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    If there is water in the clay and no easy way for it to escape (ie a glaze barrier) the steam builds up as you approach 212F and explodes. If you dry glazed pots thoroughly before heating or raise the temperature very slowly as you reach the boiling pot they won't explode.
     
  13. Alexey

    Alexey Well-Known Member Supporting Member

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    Great approach! Stem heat also provides more bactericidal effect that dry heat. Hard to overcome limitations for glazed pots.
     
  14. DeafOrchidLover

    DeafOrchidLover Member

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    You can buy new clay pot and just repot your orchid. :). If you have many then I didn't know. :)