While I haven't done this long with photoperiors, when I did autos and felt like they needed food. I went dry fertilizers for outdoor use it truly did seem the best. Using liquid synthetics outdoors especially in ground you could run into problems. Such as the rain comes and washes all the nutrients away from the roots, your mixture might not actually make it to the roots it could go off into the soil anywhere.
Just throw some top dressing fert on the top and repeat every month or so as directed.
I personally don't like
gaia green its way more expensive than needed with many other good options.
My recommend dry fert for outdoors is
fox farm it's relativity cheap and is good stuff. I paid like $200 for a 50lb bag of the two below. But if your on a smaller basis you can get 4lb bags for $10.
Fox Farm - All Purpose
Fox Farm - Fruit/Flower
There are some other dry mixes by
fox farm that are for certain type of plants. But could be used within the mix if needed.
Haven't used but heard good things I plan on trying next season.
Nectar for the gods - One shot