Seeking help in curing my sick crops in my gardens.

Good morning friends! How's everybody? I wanna find out how I cure my sick plants in my gardens and saw the yellow in my potatoes also with brown leaves and and diseased spots.
Also saw some purple on my cabbage leaves and white patches on my leaves of my tomatilos. There's some more yellow from my Mexican Yam in my big pot. Any natural ways to save them from greater rot? Still don't know how I send pictures of my crops on this site, but send them to a friend who's a long time member of this site.
Please shoot back if you need me. Have a good day.

Yellow on potatoes with brown leaves is often a sign of blight starting, especially if the weather has been wet. The purple on cabbage leaves is usually a phosphorus issue, common in cold or waterlogged soil. Worth checking drainage first before trying anything else.

What's happening! I've heard there are recipes mixed with peroxide or turmeric and could those work to help cure plants that have been in such conditions such as watering excessively, fertilizing too much and stuff like that. Summer is coming soon in Zone six in Chicago, how I prepare my plantings for the intensive heat that have a dreadful effect on their growth and those things?

It could be your potatoes are ready to dig and just dieing back?
When did you plant them?