This is not for accident prone people. Do not burn your tractor or garage down.
If you are praying for the tractor to start because you need it NOW, try warming up the manifold with a spotlight so the gas vaporizes instantly rather than trying to pull cold, heavy gas up into manifold and flooding the plugs.
With an almost dead battery quite often it will be enough to catch and run. If no electricity is available a torch will work but around gas it scares me to suggest it as I don't know if you have a gas leak. Even with the spotlight don't forget it where it shines on the carb or tank for a long time. Those heat lamps from TSC get HOT!
Have also found my automatic battery charger will never totally charge up a six volt battery. May be just mine but the manual charger even at four amps. works better. A slow charge is better than a quick boost. A 100 amp hour battery that is 50% discharged will take 50 hours at one amp to recharge at least but seems to work far better than a quick charge at high amps. Keep the battery super clean on top so it won't discharge thru the trash that builds up on top. Every time I refuel I take a gallon jug of water with a paint brush attached to clean the top off before I start it. If I work it heavy I clean it off when I finish also. Battery installed december of 2000 and still using it.
This has worked for me and might for you but PLEASE don't get hurt heating that manifold up. IT's too close to a holiday to spend it in a hospital or at a homeless shelter.