Either the battery has a dead cell, which will require you to replace it, or something is on pulling power from the battery. Disconnect the negative cable and leave it off overnight. If the battery is dead the next morning the battery is defective. If not, then find out what is pulling power from the battery. Ignition switch may be defective.
Remove it from the tractor and store it in a non-freezing location on dry wood boards. Do NOT store it on the concrete floor.
I assume you mean a car battery. Yes, you can jump your lawn tractor with a car battery, following the usual precautions for jumping any vehicle.
Usually 6v, can be 12v.
weak battery?
I usually do over night.
Yes,its attached to red wire on battery
It uses a 12 volt lawn mower engine battery.
Yes, a lawn tractor can be jump started with a car battery, in the same manner as another car can be jump started.
Battery is 12 volt, U1 group
Most take a 6 volt battery.
Usually 12 volt negative ground.
If it is a model from the last fifty years it is a 12 volts battery.