Plants that are grown hydroponically are dependent on a liquid nutrient solution to provide them everything they need because they don't have access to minerals from the soil. A good hydroponic solution will supply a complete range of the necessary nutrients, in the proper balance. A water-soluble fertiliser such as Miracle-Gro can be used as the basis of a hydroponic nutrient solution, when mixed with other essentials, in the proper proportions.
What Plants Need
Plants require 13 elements to grow. They normally draw many of these from the soil, water and air. The most important of the elements are phosphorous (P), potassium (K) and nitrogen (N). The other necessary trace elements are boron, copper, manganese, magnesium, zinc, molybdenum, chlorine, sulphur, iron and calcium. Each element is needed in different amounts, and each has an important function in the life cycle of the plant.
Miracle-Gro contains essential nutrients for plants. The main ingredients are phosphorous, potassium and nitrogen, but it also contains many of the essential trace elements. Because there are many different formulations of Miracle-Gro, and each one is slightly different, the exact amount of nutrients varies from one blend to the next. It is important to match the specific Miracle-Gro product to the plants being grown in the hydroponic system for best results. If there is no exact match, use the all-purpose Miracle-Gro fertiliser.
Making Nutrient Solution
To use Miracle-Gro in a hydroponic system, it needs to be mixed with water. According to the University of Florida website, a good hydroponic nutrient solution can be made by mixing 2 tbsp of water-soluble Miracle-Gro with 1 gallon of water. Add 1 tbsp of Epsom salts to the mixture, and mix well. Adding more than the necessary amount of fertiliser to the water can do more harm than good, so measurements should be made carefully.
Use the Miracle-Gro mixture in a hydroponic system in the same way as any other nutrient solution is used. The solution should be mixed fresh just before use rather than being made ahead of time and stored. Any crystals or granules must be completely dissolved before the solution is added to the system. The system must be periodically drained and refilled with fresh solution to prevent the build-up of excess salts and minerals that can damage the plants. Fresh water is usually used instead of nutrient solutions for keeping the system filled in between complete changes.
- University of Florida IFAS Extension: Building a Floating Hydroponic Garden; M. Sweat, R. Tyson, R. Hochmuth; November 2009
- Mother Earth News: Mother's Mini Manual for Hydroponics Growing
- Mother Earth News: Hydroponic Nutrients -- Fertilizer for Your Hydroponic Garden; Stewart Kenyon; February/March 1993
- Scotts.com: Miracle-Gro All Purpose Plant Food