S/B the tea bag method do you put the tea leaves on the soil or in our case our Hydrangea's are in tubs should we mix them with water? the same goes for vinegar and as you say dilute vinegar in water when watering the Hydrangea and what would you suggest a tablespoon of vinegar?
I think with tea leaves (or coffee grounds, or ericaceous compost, or peat) you could top dress soil around an existing plant, depending on how shallow the roots are, you could mix into the top soil. I would do this in the autumn, preparing the plant for next year. A slower acting, but longer lasting solution. If you are potting a new hydrangea, I would mix into the soil going into the tub.
The key is knowing the pH before you start changing things, you want to target a pH range (see my first reply).
Test strips for testing pH are an economical and reliable way to find out the pH, here is a link to a video that explains how to do it (easy):
https://diygardening.co.uk/products/soil-testing-kits/ The video is a good one because he is testing specifically to make his Hydrangeas blue!
The man in the video talks about making distilled water, but you likely can just buy distilled (or de-ionized) water, especially in a pharmacy. There are many brands of test strips out there.
This web site tells you how to use cider vinegar:
https://www.capegazette.com/article/change-colors-your-hydrangeas-whim-pink-blue/208098 I would definitely not use vinegar unless you test pH first. I think if I was trying vinegar, I would only use it once per growing season, as the plant is growing in the spring. It is a temporary fix, but fast-acting.
Good luck RW, post some pictures when those Hydrangeas bloom!
