Having six ounces of cannabis or less, and using it on private property has been made legal in New Jersey for individuals aged 21 and above. That translates to you not being charged criminally for possessing weed. And now it has been fully legalized to buy or sell not only medical marijuana but also recreational marijuana in New Jersey to people aged 21 and above, as state officials have written regulations and awarded licenses to seven businesses (for now) that will make up the new legal cannabis market.