Monday, 2 May 2016

Soaking Peas in Hydrogen Peroxide Before Planting

So here is something I have been doing for a few years, off and on, with some our seeds. It started when I bought some beans (from a well-known old American seed house, but one now reduced to selling in box stores) that turned out to be infected with anthracnose. I've been struggling with eradicating it ever since.

Someone suggested soaking them in hydrogen peroxide (H2O2) and it definitely seemed to help. I still have anthracnose in the beans, but it starts out slowly and really doesn't pick up speed until late in the season.

We planted the last of our peas over the weekend (yes they are going in LATE, what else is new?) and we decided, kind of on a whim, that it might not hurt to soak them in H2O2 too. Mr Ferdzy did a quick check on the internet for information about how much and how long, and came across this little article: Role of H2O2 in pea seed germination. It's mildly technical, but what I came away with is that the H2O2 is not only useful for killing fungus or bacteria that may be on your seeds but, at least in the case of peas (and from anecdotal evidence many other seeds too), may actually improve germination and viability.

One of the mildly technical points that made the article difficult for us to use was that they described the strength of the H2O2 in mM, which is not a unit of measurement found on bottles sold in the drug store. From what I gather, it seems that the maximum strength they used would be roughly equal to about 60% H2O2. At that level, some damage was done to the emerging seedlings.

However, since the H2O2 available in drug stores or grocery stores seems to be about 10%, we decided it would be safe to use it straight up! We didn't quite have the nerve for that, and diluted it some more - down to about 2%. Our peas soaked it right up (we soaked them for about 24 hours) and indeed you can see from the picture that we didn't put enough solution over some of the peas. If they come up spottily I will assume the unsoaked peas on top were slower to germinate.

My conclusion is that I have been much too timid in soaking my seeds in H2O2. I've always regarded H2O2 as a kind of mild bleach, and consequently have treated it with a fair bit of caution. I am not wrong. It should be treated with caution, and if you get it on your skin it should be washed off promptly. Still, when it comes to planting my beans this year, I am going to try soaking them in H2O2 straight from the bottle and for 24  hours. Previously, I soaked them in about a 4 to 1 water to H2O2 solution, and for no more than a few hours. I hope this will make a bigger difference in killing the anthracnose spores, and that I will finally have anthracnose-free beans again.

Have you used H2O2 in planting your seeds? What concentrations did you use; how long did you soak your seeds; and what were the results?

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