How do you sterilize clay orchid pots? Would baking them in the oven kill mold? What temperature and for how long? Would a bleach/ water soak work, or accumulate in the clay and kill roots?
I don't know how sterile my method is, but I use something like Clorex Clean-up, or Fantastic with Bleach, or even straight bleach. I spray the pots, let them sit in the sink for a while and then rinse them off with water. I let them air-dry. Sometimes, if I'm lazy, I'll just spray them, rinse and use them right away. The bleach kills alge and moss and hopefully virus. The soap in the spray kills the bacteria. I've even put them through the dishwasher when I'm really lazy.
The best thing I've found is to clean all the dirt off as well as you can and then run it through the dishwasher, including the soap. You can also spray them with bleach, if there has been mold, but the machine will do a good job.
About virus. Bleach will not kill it, nor will the dishwasher. That is why we use a torch on shears between plants. If you have a confirmed case of virus, throw the pot away.
I clean my clay pots by soaking for 24 hours in a solution of physan, then use a dishbrush (committed, not the one I use on dishes) if needed, and rinse. If I'm busy, they could stay there for several days.
That gets off the algae, the fertilizer crust, etc.
Obviously they're not sterile, but it's good enough for phals to thrive, even tho re-used many times.
A pediatrician once told me he sterilized bottles for his first child, but by the fourth he didn't bother any more.
I do torch my cutting tools.
My routine pot sterilization method is to brush the pots clean and then give them a good soak, at least several hours or overnight, in a solution of l part bleach to nine parts water, being careful not to let them nest together. Then I give plastic pots a quick rinse in clear water but let the clay ones soak for an hour or so in case there is a bleach residue that might harm the orchids. I'm not aware of any problems from the clay pots.
I always thought bleach killed virus. If a clay pot is soaked for a few hours (even one hour), I believe virus is distroyed.
I think bleach does kill the virus. I disinfect pots in bleach solution and rinse thoroughly. Now here's the BUT - rinse clay VERY thoroughly and let air dry. Then smell the pot. If you can smell the bleach, rinse again and repeat process. Bleach will eventually disappate on its own but I don't want to smell it at all before I store it for future use.
best thing that we use is a 10% bleach solution. Soak the pots for an hour or two then rinse off and sit in the sun for 2 days, this will disperse the rest of the bleach
Orchiduyftl and I are of the same mindset--
I have a trash can I use for this little task--that I HATE. I use about 10% bleach and fill it up with water. I throw the pots in there during a repotting session. After a week and I absolutely nothing else left to do, I'll certainly get out there and scrub (with little effort) what little is still on there--it come off very easily. Then I'll sit them out in the sun until I have nothing left to do the next weekend but put them away. I usually won't use them until the next potting session.
The lazy way is the way to go...
Do you have a microwave oven ? Put them in there for three minutes on high. No chemicals needed.
If your oven has a self-cleaning cycle, fill it with pots (terra cotta only, please! No plastic) before you start the cleaning cycle. I find I need to add about 30 minutes extra so the oven actually gets clean...3 hours at over 500 degrees kills *everything* (fungus, algae, virus, critters) and reduces all old bits of root, medium, etc. to a dusting of ash. Allow everything to cool off completely before removing from the oven. I have never had a pot crack or break using this method.
I like the idea of using the oven, but my husband is afraid all that weight will warp the oven shelves. Do you have any problem with that?
While I am not an expect here is part of a presentation given by one who is.
reprinted with permission from NHOS April 2005
Dr. Arthur Allison, Ph.D. Plant pathology
Critter Creek Laboratory
Some reagents for sanitizing/sterilizing:
Bleach such as CloroxÂ10% solution (1 cup of bleach in 9 cups of water)
Sodium Hydroxide (lye) Â 1% solution (1 pound can in 99 pounds of water [~12 gallons]
TSP (trisodium phosphate)-- saturated solutionÂadd solid to (warm) water with stirring until no more will dissolve and then a little bit more so there is always undissolved solid on the bottom of the container. It requires approximately 1Â½ pounds of TSP per gallon of water.
Remember to wear eye protection, gloves and water repellant apron when preparing and using these materials.
Soak cutting tools for 3 minutes before using again. Even better give them a brushing in the solution at the start of the "soak" Give workspaces 20 minutes of soak time.
A propane torch is good for sterilizing cutting tools. Heat the blade to just before it turns red. I know that this is hard on secateurs, so buy cheap ones and throw them away when they become unusable.
Single edge razor blades are great when their use is feasible. Use once, drop them in a can and then sterilize in an ovenÂ2 hours @ 400 degrees F.