[Oberon]

At Lowe's I found a bag of something called Ironite fertilizer. It has a full set of minerals and trace elements required for plant growth, so if your taters are suffering some something weird like Boron deficiency, that will fix it.

You have to be careful not to overapply, though, as some of those trace elements can hurt the plants if you give them too much.

Curling leaves, though... that sounds like a bug to me, not a nutrition problem. Do you see any critters or eggs inside the curled leaves?

[Daffynition]

Thanks for your great ideas. Outside of taking a soil sample to our university extension/ag center ...I may just guess what is wrong. I mean, it's not very serious [yet] ....but temps are getting hot & humid....so other things can happen if plants are compromised.

Fortunately, I see no creepy crawlies...only critters are the deer and rabbits......raccoons are watching the corn stalks for their annual attack on the bounty.