Our home is a farm, which is a side business. Do I claim the full mortgage interest or a percentage of the mortgage interest based on the percentage that is the farm?

[DianeW]

For the farming portion of your return you should use the percentage of the interest that applies to the farming activity.  The remainder should be used on your itemized deductions as personal expense.  

You can do the same thing with the property taxes, unless the tax assessment includes specific farm building structures that are used only for farming.  If this is the case use the combined assessment for farm structures divided by the total assessment to arrive at the correct property tax deduction on the farm portion.