Spain's Civil Guard said the four large greenhouses containing the plants were "perfectly camouflaged" to blend in with other greenhouses and orchards in the region of Puerto Lumbreras.
The five men who were arrested were "experts" in the cultivation and genetic modification of marijuana, a statement from police said.
Police found the greenhouses in August after four known criminals robbed the property, TheLocal.es reported Tuesday. Those four men were also arrested.
2014: The Year in Music [PHOTOS]