Why are your squash leaves turning yellow?

Here is an answer from the forums at gardenweb.com...

"You need to get some EPSON Salt this adds Magnesium and Sulfer and will fix the problem. Add in water or put strait around your plants: one tabespoon per foot plant height every two weeks. If they are yellow now! put 1/2 cup per gal of water and give to your plants."

(see link below for the full thread)