What causes geraniums to have red dry leaves and very few blooms? These...
What causes geraniums to have red dry leaves and very few blooms? These plants are in outdoor flower containers.
Steele County Minnesota geraniums
This sounds like the problem could be magnesium deficiency, but the only way to determine for sure is through a tissue test. Since I don’t know where you live, try putting up the some shade cloth to see if that improves the situation. It also could be from a heavy metal contamination in the water supply, but that wouldn’t be the case if the water is coming from a potable source. These are my best guesses.