I’ve been looking at feed schedules I’d recommend looking at the one for whatever brand you use. But it looks like they most definitely need nitrogen for awhile in flower, makes sense since they double in size before they start to flower.
Here is ff schedule just to give you an idea.
https://www.foxfarmfertilizer.com/images/pdf/canada-Soil-schedule-ENG_4-2018.pdf
I am basing my grow on the trio formula (green) even though I didn’t buy the big grow I bought the big bloom (not sure why it’s not in the Canadian schedule) and considering tiger bloom. It gets a little confusing because the directions on the bottles are different from the schedule. The directions on the bottle are only if your using the one bottle, the directions on the schedule are for using the trio or duo together at the same times sometimes lol. Seems excessive to me to give a plant a dose of veg and bloom and micros all in one dose at certain parts of the grow, however ff nutes aren’t overly strong with grow big NPK ratio 6-4-4 and tiger bloom is 2-8-4 even their flowering formula has small amounts of nitrogen.
Sorry if I’m confusing you the big bloom I bought is basically an iron supplement with trace amounts of organic nutes 0-0.5-0.7 made from worm castings, bat guano, kelp and something else maybe. For whatever reason it’s not on the Canadian schedule but it’s part of the trio here.
https://www.foxfarmfertilizer.com/images/pdf/usa-soil-schedule-english_3-2018.pdf
So even though I’m not using there veg nutes I’m using their schedule to get an idea of what the plant needs at what time, and to cut the strength if giving more than one food type.