Beginning hydroponic gardeners often purchase premixed solutions to use in their systems. However, you may wish to mix your own hydroponic solution to make a nutrient combination tailored to a specific plant, or to conduct some experiments in your garden. Check greenhouse supply, fertilizer or chemical companies for the nutritive salts needed for homemade solutions. Although there is no one perfect hydroponic solution, the Alabama Cooperative Extension offers the formula for a good general hydroponic solution for slow-growing plants, or plants growing in low light.
Measure 10 gallons of water. Add 2 tsp. of potassium phosphate, 2 ½ tsp. potassium nitrate, 4 ½ tsp. calcium nitrate and 4 tsp. magnesium sulfate to the water and mix well to create solution 1.
Mix 1 ¼ tsp. of boric acid and 1/10 tsp. magnesese chloride in 1 qt. (4 cups) of water. Measure out ½ cup of this solution and add it to solution 1.
Stir ½ tsp. of chelated iron into 1 qt. of water in the small mixing container. Add 1 3/5 cups of this solution to solution 1. Mix well.
Test the pH of solution 1. For most plants, a desirable pH level is between 5.5 and 6.5. If the pH is greater than 7, add a few drops of white vinegar to the solution and check the pH again. If the solution has a pH lower than 5, add a little bit of baking soda to increase the pH, stir and recheck the solution. Continue making adjustments and checking pH until you achieve the desired pH level.
Add the solution to your hydroponic garden, as needed. You may reuse this solution, applying one to three times per day, for up to 14 days.