General potato growing guideline. http://www.gardening.cornell.edu/homegardening/scenec6be.html
Prefers well-drained, light, deep, loose soil, high in organic matter. Unlike most vegetables, potatoes perform best in acid soil with pH 4.8 - 5.5. (Scab is less of a problem at low pH. If pH is more than 6.0, use scab-resistant varieties.) Needs plentiful, consistent moisture.
Sometimes grown in barrels or stacks of old tires filled with compost.
My soil is about 5.2 pH so I've had decent luck growing them. Blueberries grow wild here and they like low 5s for pH. Just picked up some lime for my raised beds so I can raise the pH and grow things that haven't done well with this low pH. Carrots are one.
From their carrot page. Prefers pH of 6.0 to 6.8 but can tolerate 5.5 to 7.5.
Seems like you need two different pH levels. A sweet spot might be 5.8?
Spinach, beets, broccoli, cauliflower, cabbage, swiss chard, carrots, onions and leeks are all things that do bad with my low pH. I can plant seedlings and two months later, they may still be alive but haven't hardly grown and some like spinach, beets and leeks, haven't grown one inch. They all need 6+ pH. Carrots are tiny and pale. Even lettuce and peppers don't do great.
Guides to 58 garden vegetables. (Each profile contains a detailed description and growing instructions, site and soil requirements, varieties, and solutions for managing pests and diseases.) http://www.gardening.cornell.edu/homegardening/sceneb771.html
I could have some mineral deficiency that's affecting things as well but the easy and obvious thing is raising the low pH. If I can get it up one point to 6.2, that should be good for most things. Going to get a DIY pH test kit first, mix compost with unknown pH in, test pH and then lime.
Alright all you flower girls. 269 flower growing guides - http://www.gardening.cornell.edu/homegardening/scenee139.html
I can test for pH. It’s been awhile. Thanks for the info. BTW what your doing with technology and gardening is amazing.