Pretreating seed to kill viruses etc

[mensplace]

I have read of the following as ways to pretreat seed:
1. Soak in a 1 part cholorine to 4 parts water for 40 minutes
2. Soak in 120 degree F water for 20 minutes

Both seem harsh, but I AM NOT A SCIENTIST! Do not attempt this unless you know them to be safe. My question is, how necessary are such efforts. Are such pests really that likely to be transmitted on seed? If so, should either method be used by total rookies like myself?

Is this even something that is worth worrying about?

[travis]

The ratio of 1 part household bleach (which is 5.25% sodium hypochlorite) to 4 parts water is correct. But 40 minutes in that solution is excessive and may result in sterilizing the endosperm. I've seen 40 minutes mentioned as the absolute extreme, but it's not necessary. One or two minutes in the 1:4 solution while stirring will do just fine.

I've never done the hot water bath, which is intended for killing pathogens INSIDE the seed hull, because it's trickier to measure and monitor, and I just never saw the need. I guess if you have severe problems with the types of pathogens that hold over inside the seed, you may want to employ that technique. Your temperature and soaking time is correct.

Other than the bleach bath following a normal 2 - 4 day ferment, the only other chemical treatment I use is a brief soak in trisodium phosphate (TSP) following a short ferment where high ambient temperatures in the garage or shed midsummer often result in seeds germinating in the mash if I let the ferment go full term. In those cases, I ferment just long enough to break down the gel a bit and then soak the seeds a couple minutes to maybe 4 or 5 minutes in 1/4 to 1/2 teaspoon of TSP in an ounce or two of water followed by a good scrub on a screen and a thorough rinse before drying.

When receiving seeds from an iffy amateur source, I will give them a brief soak in hydrogen peroxide to knock off any pathogen possibly lurking on the seed coats.

Some members use an Oxiclean method and will give you the details. I have done it but notice the presence of heat building up in the reaction and that bothers me a bit. Others have reported 100% or near 100% germination following their Oxiclean seed cleaning. I just get jittery about it because I've seen it foam up and get kind of warm.

Remember to thoroughly rinse you seeds after using any chemical treatment.

[carolyn137]

Originally Posted by mensplace

I have read of the following as ways to pretreat seed:
1. Soak in a 1 part cholorine to 4 parts water for 40 minutes
2. Soak in 120 degree F water for 20 minutes

Both seem harsh, but I AM NOT A SCIENTIST! Do not attempt this unless you know them to be safe. My question is, how necessary are such efforts. Are such pests really that likely to be transmitted on seed? If so, should either method be used by total rookies like myself?

Is this even something that is worth worrying about?

I don't worry about it.

If saved seeds have been properly processed by fermentation or other methods, most of the contaminating pathogens, if there are any, are greatly lessened in those procedures.

And most fungal pathogens are on the exterior of the seed coat, if there are any, and most bacterial pathogens and viruses are in the interior of the endosprem and aren't inactivated other than by hot water treatment which is tricky and also lessens seed viability and which you mentioned above. It's generally done by seed companies for their commercial customers and if you look in certain seed catalogs you'll see hot water treated tomato offered, for a higher price.

Most of the work on seed coat contamination was done by Dr. Helene Dillard ( I think that's her last name) when she was at the USDA station in Geneva NY and had several grants from either Heinz or Campbells.

So I've never treated seeds with clorox or anything else, be they saved seeds or commercial seeds. I know that some others do and that's their choice.

I know of her data with respect to fermentation and her comment that it doesn't remove all surface pathogens but since infection is a quantitative process it certainly cuts down on that probablility.

I've not seen any data referable to TSP or Oxi-clean or Comet, with regard to the efficacy of pathogen removal. There are several threads about those methods that are here at Tville.

So I ferment saved seeds and that's that.