Soil sterilization

Shapshftr · February 7, 2021

Often times people are plagued by dreaded damping off disease. To date I have only heard recommendations for preventing or halting damping off by using soil sterilization, or hydrogen peroxide prior to planting, or after damping off has begun. Baking your starter mix in the oven is nasty! Soaking it in peroxide is a much more pleasant method.

I have a novel idea to prevent damping off. Has anyone ever considered putting the seed starter mix under UV-C germicidal lights? I have yet to see any suggestions for that purpose. You can buy the UV-C tubes to use in fluorescent fixtures, spread the mix out thinly (the light must penetrate all the way through) on a large tray or table top covered with plastic. Then hang the lights over it for 24 hours, before potting up the mix to plant in.

This is just my own idea for soil sterilization. UV-C kills bacteria, mold, fungus and viruses. It seems so much easier than the old method of baking the soils in an oven, not to mention avoiding that odor in your house. And when you're done you can switch out the tubes with regular full spectrum light tubes for growth. What say you all?

I plan to buy some of these tubes to use for various types of disinfection around the house, so I may employ them for my seed starter mix, even though I haven't had damping off for many years. Maybe the reason for that is I use only full spectrum lighting, which would have a small amount of UV-C in it.

WARNING, when using UV-C lights you need to avoid looking directly at them and prevent prolonged skin exposure. Also make sure they aren't the type that produces ozone. Some do and some don't. These tubes are "Ozone free".

https://www.bulbamerica.com/products...20018524258426

Whwoz · February 7, 2021

Big problem I see is that UV treatment is surface only, any bacteria, fungi etc inside each soil particle will quite happily survive. It is the reason why UV sterilization has not been widely taken up.

Shapshftr · February 7, 2021

That's why I said it would have to be spread thinly And the mix could be turned a few times to get better coverage. It's being used in so many ways now, air, waters surfaces, and especially for Covid. Because of that, prices are insane.

PaulF · February 7, 2021

Too much work for me. Better to monitor watering the seedlings for the first couple of weeks. Weakened plants succumb more easily. Damping off has never been a problem here so that's why I don't see the need to do anything extra.

oakley · February 7, 2021

I think soil is just too dense for UVC. Works well on hard surfaces after a good attempt at sterilization via cleaning first with
physical methods. Hospital settings. Running UVC post cleaning surfaces, it will do yet another air and surface sterilizing....
with all surgical instrument in a heat/steam sterilizer. It just cannot sterilize the slightest shadow.
A grain of soil will have a shadow side, clearly unsterilized.
Manufacturers did run wild and took advantage of consumers. Still at it. It has been abandoned by all applications for covid.

A speck of salmonella raw chicken skin on your counter will not be sterilized no mater how long it is under UVC. (it has a shadow side). The side sitting on the counter. Think microscopic.

Use soap, (counters). Use heat, (soil). 2 trays of soil in foil pans with foil on top....easily will fill two seed start trays. Easily sterilized in your oven.

An operating room is doing all they can to prevent secondary infections. And the recovery rooms. Heat sterilized sheets, etc.
I do agree that air sterilization is effective passing multiple times through UVC purifiers.

February 7, 2021	#1
Shapshftr Tomatovillian™ Join Date: Jun 2016 Location: Illinois Posts: 162	Soil sterilization Often times people are plagued by dreaded damping off disease. To date I have only heard recommendations for preventing or halting damping off by using soil sterilization, or hydrogen peroxide prior to planting, or after damping off has begun. Baking your starter mix in the oven is nasty! Soaking it in peroxide is a much more pleasant method. I have a novel idea to prevent damping off. Has anyone ever considered putting the seed starter mix under UV-C germicidal lights? I have yet to see any suggestions for that purpose. You can buy the UV-C tubes to use in fluorescent fixtures, spread the mix out thinly (the light must penetrate all the way through) on a large tray or table top covered with plastic. Then hang the lights over it for 24 hours, before potting up the mix to plant in. This is just my own idea for soil sterilization. UV-C kills bacteria, mold, fungus and viruses. It seems so much easier than the old method of baking the soils in an oven, not to mention avoiding that odor in your house. And when you're done you can switch out the tubes with regular full spectrum light tubes for growth. What say you all? I plan to buy some of these tubes to use for various types of disinfection around the house, so I may employ them for my seed starter mix, even though I haven't had damping off for many years. Maybe the reason for that is I use only full spectrum lighting, which would have a small amount of UV-C in it. WARNING, when using UV-C lights you need to avoid looking directly at them and prevent prolonged skin exposure. Also make sure they aren't the type that produces ozone. Some do and some don't. These tubes are "Ozone free". https://www.bulbamerica.com/products...20018524258426

February 7, 2021	#4
PaulF Tomatovillian™ Join Date: Jan 2006 Location: Brownville, Ne Posts: 3,295	Too much work for me. Better to monitor watering the seedlings for the first couple of weeks. Weakened plants succumb more easily. Damping off has never been a problem here so that's why I don't see the need to do anything extra. __________________ there's two things money can't buy; true love and home grown tomatoes.

February 7, 2021	#2
Whwoz Tomatovillian™ Join Date: Jun 2013 Location: Victoria, Australia Posts: 870	Big problem I see is that UV treatment is surface only, any bacteria, fungi etc inside each soil particle will quite happily survive. It is the reason why UV sterilization has not been widely taken up.

February 7, 2021	#5
oakley Tomatovillian™ Join Date: Jun 2015 Location: NewYork 5a Posts: 2,303	I think soil is just too dense for UVC. Works well on hard surfaces after a good attempt at sterilization via cleaning first with physical methods. Hospital settings. Running UVC post cleaning surfaces, it will do yet another air and surface sterilizing.... with all surgical instrument in a heat/steam sterilizer. It just cannot sterilize the slightest shadow. A grain of soil will have a shadow side, clearly unsterilized. Manufacturers did run wild and took advantage of consumers. Still at it. It has been abandoned by all applications for covid. A speck of salmonella raw chicken skin on your counter will not be sterilized no mater how long it is under UVC. (it has a shadow side). The side sitting on the counter. Think microscopic. Use soap, (counters). Use heat, (soil). 2 trays of soil in foil pans with foil on top....easily will fill two seed start trays. Easily sterilized in your oven. An operating room is doing all they can to prevent secondary infections. And the recovery rooms. Heat sterilized sheets, etc. I do agree that air sterilization is effective passing multiple times through UVC purifiers.