The Greenhouse floor project moves ahead.

[DirtyCoconuts]

Use that. The pit.

From the way you describe it I would fill that pot with gravel and then keep adding gravel up until I reached the grade level of the GH, then make the interior wall with the bricks and fill as you were planning.

On the area where the pit is, add a few out pipes, so that the water doesn’t stay inside the bricks


Given the amount of water you describe, it would be well managed