chasv77answered grow question 5 years ago 5 plants in a 1 meter square area? That is a lot of vegetation(cramped?), if you don't keep them short.
At that point you are on the bleeding edge of coverage, especially when in flower.
IMO, if I had a 3'x3' box/tent, I would use at least a 400W light, but don't let me discourage you, from using what you have.
Maybe reduce the plant count to 2-3, and use fast flowering autos.
Good growing!👍