Every summer some of my plants develop brown spots. I don't know if they are mildew, fungus, insect or a soil issue. How do I tell, and what do you use to prevent? I have been spraying neem oil but don't know if that's right. Here are 3 photos of spots starting: first on a hydrangea; second on phlox; and third on cranesbill (in a different plot than the other 2)
Name: one-eye-luke US.Vet. Texas (Zone 8a) Quitter's never Win
You need to aerate the soil around the bottom of the plants to allow the soil to dry more between waterings. You are keeping the soil too wet and not allowing the plant roots to get enough oxygen between waterings. Let the plants have wet to dry cycles to keep your plants from getting disease.
NOT A EXPERT! Just a grow worm! I never met a plant I didn’t love.✌