yeah, you'd need 2 6 bulb fixtures at a minimal. That's to make sure that all plants have adequate light area. It not only depends on the lumens but the area that they cover.
I currently have 20 plants in one gallon pots under one 6 bulb T5 fixture and I'm pushing the amount the light fixture can handle. I'm not taking them to fruiting, only until Spring plant out.
So don't only think of the lumens, you have to think at what space the plants are spaced out and how the bulbs are set up as well. It is easy for tight plants to start forming a canopy top that chokes the light from getting to the lower leaves, and if you what shorter stockier plants then you need to be mindful of that.
For a full square meter, I recommend two 8 bulb T5 fixtures. Gives you plenty of space you'd need. You can space out the plants appropriately and it will let you grow them shorter and stocky. You must also think of what types of plants you are putting out and how large those types will grow. In a 5 gallon pot, a lot of pepper plants will get about 3 feet in size if not bigger.