tudedude wrote:Can adding vinegar and fert to the water cause sunburn damage ?
Yes, don't add too much of anything soluble. You shouldn't really be adding anywhere near enough to cause problems, but just one more reason to keep it dilute.
Strangely, hard water can be packed with far more minerals than you'd dream of adding as fertiliser, but no problems.
There is a measure called the salt index that indicates how likely a substance is to cause burning to plants. The salt indexes for most fertilisers are widely published, but it would be possible to calculate for other substances too.
Salt indexes for most calcium salts are very low because of their low solubility, so even extremely hard water doesn't cause burning. Likewise, salts such as calcium acetate formed by neutralising hard water pH should not be a big problem. I'll see if I can find numbers. Salt index of Calcium Carbonate is about 5, compared to 100 for Sodium Nitrate. I can't find a published value for Calcium Acetate, but it seems to calculate out around 25.