It hasn’t rained here in about 2 months so we are having to irrigate and it’s a problem. Like most rain in the U.S., our rain is acidic, around the 6 mark on the pH scale. As you likely know, in places that get a lot of rain and that have acidic soils, acid rain can be a big problem. Here it’s not as devastating. My soil is already on the alkaline side with a pH of 7.8. That acidity soaking into an alkaline soil amended every fall by leaf litter in the beds and compost spread on the lawn makes for a nice neutral medium for the plants. It’s when you have to rely upon water coming down from very rocky mountains that the trouble starts. On the hardness scale, over 10.5 is considered very hard and our water with a pH of 8.3 mind you has a hardness rating of 12 grains per gallon (beat that Spinal Tap). You can practically chew the water. It does taste very good though; they tell me high mineral content makes for a very tasty water. But the chlorotic yellowing plant leaves in my back yard tell me they’re not giving into the deliciousness.
Chlorosis AND black spot fungus. Double whammy for this Populus, but I love them.
At the first sign of chlorosis, my knee jerk reaction is to apply chelated iron, which I do with a foliar spray and soil amendments. All fine and good, but I can’t do this too much as it can build up to toxic levels, as with any mineral amendment. And treating everything with iron isn’t solving the real problem of alkaline, hard water and alkaline soils.
As I was reading through the Arrowhead Alpine’s site and found this under their seed starting link:
Beware of high pH in the water. We killed a ton of stuff due to this. We now adjust our water pH to 5.6-6.0 by injecting battery acid directly into the irrigation water along with the fertilizer…. PH induced iron chlorosis is an insidious problem. Plants weakened by it quickly fall victim to fungus gnats and aphids.
I knew this about seed starting, but after reading about the battery acid suggestion, it got me thinking. If only I could inject something like that into my sprinkler system, but that would require an expensive retrofit of my current system and I don’t think the liquid feed systems are built to handle acids. What about hand watering? I guess I could add something to the watering can, but there’s too much to water by can. Then it hit me.
Say what you will about the above company, they make a nice sprayer.
I added some seaweed emulsion to a the container half-filled with vinegar and then topped off with water. I know the vinegar solution is used up once the color of seaweed is gone. If you don’t have a dark fertilizer like the seaweed emulsion, you could add green or blue food coloring. Taking this further, I plan to put a siphon mixer on my hose with a feed tube in a large bucket of the vinegar solution if the plants respond to this sprayer method.
As for insidious biochemical reactions, I haven’t seen any yet. I figure if plants can stand dilute sulphuric acid, they can stand dilute acetic acid. That being said if anyone out there has a good sciencey reason for why this is a really bad idea, let me know.