Lumens

What would you guys say is the minimum amount of lumens needed to produce some decent bud?

Technology has advanced so much in the last 15 years that we are constantly refining the process and updating what we know works best for growing. Current theory holds that the minimum amount of lighting needed to sustain growth is around 2,000 lumens per square foot. Mid range is around 5,000 lumens per square foot. Optimal is 7,000 to 7,500 or higher lumens per square foot.

Thanks alot Major.