Pre-flower or normal growth?

Your plants are looking good and starting to flower. Since you are half Happy Frog soil you could start adding low dose nutrients. If you switch to flower nutrients make sure you continue to give them some nitrogen for at least several weeks (2-4 weeks) into flower or about until the stretch is complete. Many flower nutrients don't contain nitrogen but it is still needed for the first part of flower. If you start having the lower leaves turn yellow it might be nitrogen defficiency. I love the Fox Farms soils, especially Ocean Forest which I use in my grows. I am not a fan of their nutrients. Too many products with only slight variations and minimal if any micro nutrients. Also, their low nutrient value means you'll need more (good for them, more money for you). I'm not saying FF nutrients are bad, I just like others better because they are simpler and contain micros so you aren't having to buy 5 or 10 products. As an alternative you can consider General Hydroponics nutrients. I have had great luck with their Bio Thrive Bloom and Grow formulas. I have recently finished my first grow with their Maxi Bloom and Maxi Grow dry fertilizers. With each type one bottle of veg and one bottle of flower nutes usually does the trick though I recommend keeping a bottle of Cal/Mag on hand (brand doesn't matter) especially if you are using bottled, RO or municipal water.