Slow Realease Nute Harvest

So... I am nearing the end of flowering for my one plant.

My question is...

I used miracle grow with slow release nutes. Is there any way that I can "flush" the plant properly? I kno that I wouldnt be able to do it ith the plant still in the soil....

I kno that I wouldnt be able to do it ith the plant still in the soil.... not sure what that means, anyways it will probably be difficult, the time release pellets just tend to release more nute with more water
though by this time, they may be just about gone