Would the fertilizer advice apply to carrots, also?
Yes. All root crops like the phosphorus/potassium vibe. Flowering bulbs (Tulips, Daffodil, Crocus) and Garlic like it, too. :)
NPK = Nitrogen, Phosphorus, Potassium. You will see formulas on bags of fertilizer listed that way.
My ‘secret weapon’ is a bag of 10-18-10 new lawn fertilizer when I can find it. Works well for above-ground vegetables such as tomatoes and peppers, eggplant and okra. I also use it on all of my fruit trees.