oh man lol, right in the title. sorry. anyway, as long as youre using promix i would say you are spot on feeding 1/4 right now. I also use a soilless medium and i feed every watering and keep it nice and moist. since youre in promix its up to you to keep them fed given that they cannot get food from their medium. your plants look great too! soon youll be able to up their feeding as they get bigger. keep it up!