About three weeks depending on how fast they grow the better they start the faster I would low dose Grow Big. But honestly I try to start my plants seeds or clones and have them in the flip before they need grow big so I most of the time only need to feed Tiger Bloom and Big Bloom.
I know every one worries about over watering but if you go to Fox farms site they tell you to water heavily after transplanting. i soak my plants every few days and suck the water from the oil pans and feed heavy during flower and it works for me my soil rarely dries that much.
No the science now says nitrogen is needed all the way till the end of flower and Tiger Bloom has the perfect amount of nitrogen and works perfect with there soils which also are buffered with lime.
I have never flowered a plant without Tiger Bloom in well over ten years now I use organic bloomers also but Tiger keeps my Ph perfect with my tap water.
I always feed Tiger at the low dose first which is 15ml per gallon and then the higher dose of 20ml to 25 ml. Till harvest with no issues but I do water heavily to flush and balance my Ph with my tap water cause it has perfect ph.
You cannot flush the plant of anything it takes up the plant only can use up what is left then remove the nutrients in the medium so the plant cannot feed but you cannot remove anything from the plant.
Those fox farms nutrient charts scare me because there are so many products .Its hard not to think you need them all I would like to do a fox farms trio grow w/ purpinator
I do not use charts I feed only when I see I need to and use 15ml pre gall or 25ml. Only Tiger big bloom and grow big. And some dry organics from our sponsor Geoflora.