Soggy soil?

OK I grow in Sunshine mix 4 I've been watering my plants by the weight of the pot. The soil surface is still moist but by no means soggy or wet. The plants were healthy and over a foot tall with multiple top, but still in veg. I haven't had any deficiency issues yet till now. Just yeasterday I gave them a dose of flower ferts because I'm switching them over to flower today. Over night signs of a Phousphorus def showed up. Three possible causes of the def could be pH(fine as far as I know from yesterday), Soggy soild, or an excess or iron or zinc. According to the ferts the flower fert has double the iron but less zinc, so that could be a possibility, or it could be the soggy soil. I want to give them a good flush now anyways and give them some time to bounce back before putting them into flower. But DO I FLUSH THEM NOW WHILE THE SOIL IS STILL WET, OR DO I WAIT TILL THE SURFACE DRIES?