Brothers Le Anh Tai, 43, and Le Hoang Quynh, 31, were taken into custody for illegally growing cannabis, police said Sunday.
Police uncovered the illegal operation on March 5.
A total 900 cannabis plants ranging from one centimeter to 1.8 meter in height were found planted across more than 2,000 square meters, along with over 600 young cannabis plants nursed in plastic bags.
In Vietnam, those growing cannabis on a small scale can be fined VND2-5 million ($86.16-215.40). Farmers found cultivating 500 to 3,000 plants could face jail terms of six months to three years, while those operating on a bigger scale can get up to seven years in jail.
Worldwide, increasing numbers of countries and localities are legalizing medical or recreational use of marijuana, including almost 40 states in the United States.