For outdoor plants that are in the ground, potroast makes a valid point.....inground plants that have decent soil do well in searching for nutrients and water on their own. Benign neglect. I give my plants that are in the ground ferts only a couple of times a season. Depending on your climate you may have to water them, but I would only use water. let them get bigger by not feeding them! Unless your native soil sucks.....(you can test it,or have it tested.)
Container plants are a whole different situation.....I feed with almost every watering, outdoor container plants can take almost twice the dilute strength of fertilizer as the same plant indoors, even under a 1000 watt! The suns energy translates to more rapid growth and the corresponding need for more nutrients to grow big and strong. I use a "soilless" soil for my outdoor containers....no dirt....ProMix BX....so I add all of the nutrients.
Start off with a weaker fert mix and increase as plant shows robust growth without burnt tips.
IMO, Foxfarm is overpriced, I get same, or better results from less expensive mixes.