I always fed cuttings overwintering in the basement half strength liquid plant food every watering.

When my cuttings rooted out of their first pot with blooms that was when I started to feed them because it takes maybe a year to get them to full potential. I put a little Vodka, couple of tbls. but never measured into the gallon of water and I've never had happier blooms and so many along with a huge number of bees.