On 05/07/2015 13:37, Chris Hogg wrote:
On 5 Jul 2015 11:02:17 GMT, Emery Davis wrote:

Was wondering about this as I watched a very welcome rain shower this
morning, but couldn't find much information. Hoping one of our resident
chemists might know something about it.

We all know that root oxygenation is super important for our plants and
in pots can be difficult if soil becomes compacted and/or water logged.
One remedy I've found is using hydrogen peroxide to super-saturate water
for pots, where the plants seem to really appreciate it.

Watching the rain I imagined that rainfall has a high dissolved oxygen
saturation point. But then I wondered, since raindrops form at fairly
high altitudes, maybe this is not so? But anyway rolling across the roof
and down a pipe should oxygenate the rainwater, so that upon filling the
water butt should have healthy saturation levels. After sitting around
for a month though, perhaps not... it does get a bit of a stink to it.

Would this water be essentially anoxic and so problematic to water with?
Or does pouring it into buckets and shaking it around oxygenate
sufficiently?

Enquiring minds, and all that... TIA for any insights.

-E

I've never come across the use of hydrogen peroxide (H2O2) for
watering pot-plants. What strength do you use? I imagine it would have
to be really quite dilute to void damaging the finer roots; H2O2 is a
powerful oxidising agent, after all.

As to rain, I think regardless of how high up the droplets form, by
the time they reach the ground they will be saturated with oxygen. But
in a water butt there's a lot of sludge and organic detritus that gets
washed in over time, which will absorb that oxygen, and the limited
open surface and lack of agitation will slow the rate of dissolution
of fresh oxygen. How long that water takes to recover after it's been
tapped off from the butt, I don't know, but I would think it would
take more than just pouring it between buckets a couple of times.

These really are 'how long is a piece of string' questions.

Why not rig up a solar-powered fish-tank bubbler in your butt, to keep
it fresh?

Sounds painful.