Are your battery cables color coded?
If you as the tractor owner made this mistake, if anyone else works on the tractor, it would be easy for them to make the same mistake.
If the cables are not marked, you might get some red tape and at least tape the first 6-12" of the. ????? Cable.
Now I am confused which cable is the positive, no wonder you got them confused.
Good luck and stay safe,
could hooking the battery backwards cause the battery to blow up????