what is your floor made of? is that white sheet plastic? if so, I'm guessing it's flexible or else the heavy plant won't have any effect... I don't know if it will work perfect or last a long time, you'd probably have to see it in action, you might get lucky and it might end up directing all the water straight to the hole without leaving any pools.
If not, you might have to get crafty and depending on the price of that plastic board, buy another one and create a floor that's angled in a couple of ways to direct all water to one corner, in which you would place the drain.