You are way short on light. You've got 23 x 42 = 966 sq. in. Divide that by 144...you've got over six and a half square feet of grow area. That's enough room to grow 4-6 plants...but you'll need at least 30000 lumens of light; 35000 would be better. That's the type of space that most people would use a 400w HPS for.