I think this may be state specific to Oklahoma but I am not sure. If a couple is married, do they both have to sign the mortgage not matter what kind of real estate? I know is they are purchasing a home then they would both have to sign. What if they are putting up 100 acres of farmland they already own as collateral, would they both have to sign the mortgage? One more, what if they were purchasing 100 acres of farmland, could only the husband sign the mortgage or is the wife required to do so as well.

You are correct - this will be based on the property laws of your State - you might try the OK forum.

Yes - The wife must sign the mortgage.

1. What if she homesteads that property?

2. What if you foreclose. You would have to share ownership interest with the wife.