Among the items found at the house in Escondido were chemicals, including pentaerythritol tetranitrate, known as PETN, grenades and other weapons, the San Diego County Sheriff's Office told KGTV.
PETN was used by would-be airline shoe and underwear bombers, officials said. The new body scans at airports are meant to detect it.
Resident George Jakubec has been in jail since the landscaper was injured. He is being held on explosives charges in lieu of $5 million bail.
Most of the explosives, which were found Wednesday, were left in the house because it is too risky to move them but deputies were working on a disposal plan, authorities said.
"This is a very cluttered environment. There were items that were just stacked on every open spot," Assistant Sheriff Ed Prendergast said.
"Proactive operations on site have been suspended," he told the Los Angeles Times. "Explosive material and hazardous chemicals remain within the house."
Chemicals from a shed on the property including 4 liters of hydrochloric acid, 1 liter of nitric acid, 25 gallons of sulfuric acid and 50 pounds of hexamine, CNN reported.