Homemade Hydroponic Fertilizer

Hydroponics -- growing plants without soil, usually in a water-based solution -- can be complicated and more than many people want to tackle, but it doesn't have to be that way. A simple system using buckets or storage totes will grow lettuce, herbs, spinach and other greens in little space. Homemade hydroponic fertilizer is another easy way to simplify your hydroponic system while still getting great results. The key is in understanding what your plants need and then delivering it.

Macronutrients

Macronutrients are essential elements that plants require in relatively large quantities. Some of these, such as oxygen, carbon and hydrogen, come from the air and water. Other macronutrients that all plants need are calcium, nitrogen, magnesium, potassium, sulfur and phosphorus. If your hydroponic garden lacks any of these elements your plants will fail to thrive and may appear stunted, with discolored and drooping leaves. You may be able to tell what's lacking by the symptoms; a plant that isn't getting enough nitrogen, for example, will be small and pale green.

Micronutrients

Plants need additional nutrients, known as micronutrients, in small amounts. These include manganese, chlorine, molybdenum, boron, iron, copper, cobalt and zinc. Even though your plants don't need much of any of these, leaving them out of the mix can cause leaf problems and result in plants that are unable to grow properly. For instance, a lack of manganese will cause your plants to be stunted and to have yellow or oddly-colored leaves.

Mix it Up

To create homemade hydroponic fertilizer, the University of Florida Extension Service recommends that you find a high quality, complete plant fertilizer that contains all of the essential micro- and macronutrients. It's important that the fertilizer also be water-soluble so that it will remain in suspension and be available to your plants. To mix it up, use 2 teaspoons of fertilizer and 1 teaspoon of Epsom salts for each gallon of water, then shake or stir until the solids dissolve. Make it fresh as you need it, since some of the nutrients are lost if you store the mixture.

Considerations

Your plants will use their nutrients at different rates, depending on many different factors, such as the type of plant, how fast or slow it is growing and whether it is producing fruit or seeds. Since it's impossible to predict exactly what your plants will need at any given point, it's best to replace all of the old liquid in the system every week to 10 days. Simply adding new fertilizer to the old will cause a buildup of salts that can kill your plants.