You haven't given us near enough information.

How big is the area?
What are you growing?
Are you just starting seedlings or growing full plants?

In general, you should aim for 3000 lumens/sq.ft for growing full size plants.

Sounds right...

A very approximate watts to lumen conversion is about 85 lumens = 1 Watt (T5). 50 watts of T5 per square foot is recommended by some hydro people for the best flowering plants.

That comes out to a bit over 4000 lumens/sq. ft. but some plants with lighter loads require half that, 2000 lumens/sq. ft. as a minimum feasible. If you use the low power end it is very important to take care to get uniform lighting and keep the lights as close as possible.