Use a 5 to 10% bleach/water solution (precise measurement is not necessary, you can guess). After the trays have soaked for a few minutes, rinse well until they no longer feel slick.

Hi Suze9 and the group, Thanks for the info. I did not think of soaking the trays in a tub. was going to try spraying them but I like your idea of soaking much better.

Take care, DC

There are other sanitizers that will work but bleach is by far the cheapest and works extremely well unless too much organic material is in your recycled trays or cell packs. The only time you really need to rinse is before dipping in the 5% bleach solution if a lot of residue exists. A long soaking is not necessary... it works quickly. Be sure all surfaces are wetted and then allow the dipped trays to dry before use, preferably in a well ventilated area for the first hour or so. The chlorine will evaporate off during drying. Plan to dip trays in the bleach mix within one hour after you make it up since the chlorine will also evaporate off if you hold the mix exposed much longer. Wear long rubber gloves to prevent your hands and arms from excess contact. If you splash it onto your clothes, you will notice color fading and even holes after next landering... the same is true of the thin cell packs and trays after prolonged soaking (or many years of dipping).

Make sure you treat all of the recycled plant contact materials, within reason. Contaminated benchtops, tools and held over plants are common sources of plant diseases. I usually do the lesser contact surfaces last.

I just put them on the top rack of the dishwasher upside down. I don't use heated dry of course! It seems to work well.

How about dipping containers in boiling water?

Some plastics will deform or warp if immersed in boiling water but otherwise I think it should work. I've never been one for trying to sterilize any pots (or tools for that matter) so don't take my word for it.

Harry

I'm kind of with you there, Harry...it's kind of like a person being a hypochondriac. But I can understand it with people in the nursery business with thousands of dollars and their customers' satisfaction at stake. Thanks for the response.