Summer squash, Zucchini leaves turning white
I am growing my squash in earth boxes this year and last week i noticed one of my leaves were almost grey in color...kind of like silver. I dont think it is powdery mildew... it didnt start in circles and it does ot rub off to the touch. Slowl more and more leaves are turning this whitish grey color. They were planted from seed about a 5 weeks ago and transplanted into the earth boxes about 3 weeks ago. I dont know what i should do! Should i treat it as if it is a fungus? Baking soda and water? Is it an iron deficiancy? any thoughts or tips would be wonderful!