I've sprayed Miracle Grow for lawns, it works well. I've tried liquid iron, but it turns everything a bright green for about 3 days then begins to fade.

Any brand of fish fertilizer or kelp spray or compost tea or worm tea. You can find larger brand fish fertilizer pretty easily across the country. They smell terrible, but work great

Liquid fertilizers are very temporary. When we talk about fertilizing we talk about applying about 1 pound of N per 1,000 square feet. Since an entire bottle of liquid fert weighs about 2 pounds, and if it contained pure nitrogen food, then it would only cover 2,000 square feet. When you spray you're getting fractions of an ounce per 1,000 square feet. You'd have to spray every week or two to keep up with the plant's demand for food.