Retired and contributing to an IRA

I am retired, Married filing Jointly and My wife is still working. I went through the IRA contribution section and it told me if I contribute to an IRA I can take a tax deduction. I have no earned income. I thought you had to have earned income to take a tax deduction? My wife is unable to contribute and take a tax deduction I assume because she is covered by a 401k plan and we are over the income limit. Is Turbotax correctly saying I can take a tax deduction for making an IRA contribution?