Just got some earth juice, when to add?

I just bot a bottle of Earth Juice Grow and my plants are about 3 days - a week old. Most of them are on their first set of leafs still, some starting to grow the second. When do you think would be an appropriate time to add this to my watering and how much would you recommend adding? Thanks a lot!

I just added the 1/2Tbsp per gallon dose to my seedlings at one week old, and they loved it! But they had already started to form their 3-lobed leafs. The nice thing is that organics are hard to burn with, but start with 1/4Tbsp per gallon dose if your unsure, it may not be much but better safe than sorry.