Whenever we had some Coke in our cans that we didn’t want to finish, or some extra soapy water from washing the car, or cleaning out the car and finding almost-full coffee containers, we would often pour out such liquid onto the bushes and plants around us. The rationale was, of course, the plants needed water anyways.
But I’ve wondered…is such a practice more detremental to the environment than helpful? I’m sure there are some chemicals in there that can’t be good for plant life, but is it really something I need to worry about?
One concern is that the osmotic pressure (from the high sugar concentration) might actually draw water out from the roots, or at least force the plant to increase ion concentration in roots to overcome that pressure, consuming energy.
A friend once told me that he once poured some coke-equivalent on a frog, intending to feed it. The next day, it was all shriveled up (and dead), probably because of water leaving its tissues. Fun stuff.
I’ve been dumping half-full diet sodas and beers on my houseplant for several years, and it seems to thrive on it; I have to trim it back routinely or it gets unmanageable.
I’d be concerned about the phosphoric acid content of your coke. At 106 mg/L , it’s not going to take too long before you overdose your plants on phosphate. By way of comparison, regular old pond water runs at about 0.023 mg/L phosphates.