George Jakubec, 55, admitted to packing his house with homemade detonators and volatile explosives.
Rather than attempt a dangerous cleanup, authorities in December opted to burn the home to the ground.
Jakubec, an unemployed software consultant, also admitted to robbing three banks at gunpoint.
Prosecutors determined he was not a terrorist.
Jakubec's lawyer says his life simply took a wrong turn.
The defendant said nothing at his sentencing and told his attorney not to discuss his motives.
Jakubec, 55, was arrested in November after a gardener stepped on residue in his backyard in Escondido, suffering eye, chest and arm injuries.
Jakubec acknowledged making and storing nine detonators, 13 grenade hulls and large quantities of the highly unstable Hexamethylene triperoxide diamine, or HMDT, which can explode by someone stepping on it. He admitted having significant amounts of Pentaerythritol tetranitrate, or PETN, the explosive used in the 2001 airliner shoe-bombing attempt.
The Associated Press contributed to this report.
