Are you using potting soil or soiless mix? Because the potting soil has more than enough nutrients to keep a plant going for good month. Growbig is definately not the stuff you want to be using now. I never start feeding for a month unless
1. Its Soilless mix
2. Leaves are showing nutrient lackings
3. The soil has already been used

And in this case, you're still doing vegetation? So higher nitrogen and lower phosphorus and potassium. It seems you're just gorging them. Try using less too because 2tsp/gal is a lot of damn food for one plant.