Plants grown in hydroponic solutions need to receive all their nutrients from the liquid because they don't have contact with soil. Miracle-Gro fertilizer contains some chemicals that plants need but it lacks other important nutrients that garden plants would normally receive from soil, especially magnesium and calcium. Much of its nitrogen also isn't in a form that plants can use without soil. Miracle-Gro plant food works in a hydroponic solution if you mix it with other ingredients to provide more balanced nutrition. It's inexpensive, though the result still doesn't provide nutrition as complete as commercial hydroponic solutions.
Fill a bucket with one gallon of water. Use a bucket with graduated markings to indicate a gallon, purchase a pre-measured gallon jug of distilled water, or use a clean gallon jug to measure.
Add 1 tsp. of Miracle-Gro tomato plant food and stir with a large spoon or stirring paddle until it's dissolved.
Measure 1/4 tsp. of Epsom salts and stir it into the mixture.
Measure 1/4 tsp. of calcium chloride and stir it in. Use the resulting mixture as your hydroponic solution.