My plants all did the same thing. I replanted last weekend or so and the new cucumbers and squash look really a lot better. I thought it was the cold weather, but we just did a soil test and our soil even with the addition of the mulch we had is still very poor in important nutrients and has a pH of 7. We added the gypsum everyone has recommended for the clay soil and it also lowers the pH some and we plan on getting some of the cow manure to add to it to see if that will help.

Good luck.

Katie

Check your squash to see if you have Borers in the vine. Look where the vine grows into the ground. It will look like the vine has been chewed in to, which it has. They get inside and eat all the inside of the vine, thus the vine dies. Bad little critters these are!!! Not sure why cukes would die, but I think they may get bad bugs too. Maybe someone else will post about them. Hope this helps Mona

Hmmm...are they getting enough sun? Especially with as cool as it's been, lack of sun could be part of the problem. Ditto mlwgardener--check for borers and other bugs. And, if you haven't already, a soil test kit from Ace hardware (~$15) or other store will tell you what your macronutrients (nitrogen, phosphorous, potassium) and pH are like. Typically though, they should be okay in most of TN. Is it possible they are waterlogged? Or overfed/overloaded with nutrients?
Have you posted over on the kitchen garden board? They might have some other, more specific ideas.
Good luck!!

if the leaves are yellowing from the tips inward then it's the watering, meaning too much. if there are brownish spots on the leaves, you've got additional problems (blights). but i think that it's probably a soil issue and a soil test is a great idea plus back off on the watering and the feeding for now.

j.