The six men from London had tried to steal the £54,000 worth of cannabis from Westcliff.
However, they killed a “gardener” at the cannabis factory - Asqeri Spaho - and seriously injured another man.
However, they left weapons and other items - including a bloodstained rucksack - at the scene of the killing in Tintern Avenue.
Wesley Hendrickson, Leon Wright, Brian Kinloch, Scott Heaney, Mitchell Harris and Durald Sokoli have been jailed for a combined 112 years, with Hendrickson and Wright jailed for life for murder.
The group travelled from North London into Southend before going to Tintern Avenue, breaking into the address through a bathroom window at the back of the property.