"Betting the Farm" is a
metaphor used to represent wagering all or most of the possession you have (or
have left?) on a bet.
Things included in a bet of this magnitude might be a
house,
cars,
property (
by word or deed),
stock options (
if yours are still worth anything),
family heirlooms or other expensive non-replacable items, or combinations of the above and/or other items of value not listed.
Also may be used to represent taking
cumbersome financial risk, or dealing with other
high risk activities and/or
decisions.
Can be a sign of a
severe gambling addiction.