You can also use a small space heater ( ceramic disc, "milk-house heater", etc ), and throw an old quilt or moving-pad over the tractor.
If your L is a later model with the dipstick oil-check, I think "dip-stick heaters" are still available...
If your L is a later model with the dipstick oil-check, I think "dip-stick heaters" are still available...