Characterizing the Phytotoxic Effects of Hydrogen Peroxide on Common Microgreen Species and Lettuce Cultivars

And a PhD dissertation

Yup, at almost all costs.

Not to disagree with Keith, but I broke 5 ribs due to leaving a moving motorcycle prematurely. Also broke my collar bone. Overnight stay and every post crash test they could think of, then surgery. Fortunately, there were no ill effects from the hospital. Just my bruised pride. :backtotop

Was the departure voluntary or involuntary? Either way does sound painful.

I kind of did this experiment early this year with four mini phals. Two purchased from Trader Joe’s at the same time and two from an orchid nursery. The TJ ones had moderate and severe root rot. The nursery ones had relatively healthy roots but one had moldy media.

All were repotted the same week, into similar media and slotted pots, and treated with spraying 3% peroxide on the damp roots.

The healthier TJ mini phal and nursery phal had no issues with it. They maybe paused growth for a month or two but both are now some of my healthiest and most floriferous orchids.

The TJ one with worse roots died, and upon dissection I did find a purple ring. The nursery phal with moldy media lost all its roots but I was able to nurse it back to health (see my recent post).

My conclusion? Peroxide is not a cure all nor a sure killer, and its suitability for use probably depends on what’s actually ailing the orchid and its current state of health. I would continue using it judiciously on mild cases of root rot and expect a period of stall afterward, but wouldn’t use it on severely stressed plants.

Although Hydrogen Peroxide does have antimicrobial properties, it is not recommended for orchid care. The oxidizing properties of Hydrogen Peroxide on your orchid roots will burn and destroy the healthy velamen that protects the roots, hindering their absorption.

Well hydrogen peroxide may not be helpful but it doesn't really hurt at low concentration.

Quite involuntary. Hit a slick spot in a corner on a new rear tire. Bad combination. Fortunately I was going about 10 mph when it occurred. And yes, it hurt.

Alan Koch of Gold Country orchids was a proponent of pouring H2O2 through the medium to “oxygenate” it. He told me he bought it by the pallet.

I view that as a risky practice, but when you consider that the peroxide decomposes almost instantly upon contact with organic material, maybe the risk is lessened a bit.

I spent a lot of time talking to the technical director at BioSafe Systems, who sell hydrogen peroxide products for horticulture, and he explained it as being a difference in concentration and stabilization.

Drugstore peroxide is typically 3% active and is mildly stabilized with stannous chloride. When the H2O2 to H2O reaction commences, it is a fast, relatively “violent” release of energy.

Their H2O2 products are designed to be delivered at a much lower concentration and are stabilized with peroxyacetic acid, which allows it do decay at a much slower rate - hence a non-damaging energy release - staying chemically active until it dries.

I used their Zero-tol product in my greenhouse for years with no issues.

Outstanding post, Ray! It explains a lot.

-Keith