When growing hydroponics, there are a vast variety of growing mediums that may be used. The mediums include materials, including perlite, vermiculite, coconut fiber, gravel, sand, or any number of other materials. Even air may be used as a hydroponic growing medium. The hydroponic growing medium is an inert substance that does not supply any nutrition to the plants.

All of the nutrition comes from the nutrient solution, typically combining water and fertilizer. Hydroponic fertilizer and fertilizer intended for use in soil (regularfertilizer) contain the three main nutrients. These nutrients are nitrogen, Phosphorus, and potassium. The main difference between hydroponic fertilizer and dirt fertilizer is that hydroponic gardening fertilizers contain the proper amounts of all of the essential micro-nutrients that regular fertilizers do not include. The plants are expected to find these elements in the soil.

Problems may arise for the plants if any or all of the micro-nutrients are not present in the soil or have been depleted by successive or excessive plantings. Hydroponic gardening fertilizers are usually in a more pure form than are regular fertilizers so they are more stable and water-soluble.

Organic fertilizers are typically very different than either the hydroponic fertilizers or the dirt fertilizers in how the deliver nutrients to the plants. The organic fertilizers rely on the action of bacteria and microbes to help break down the material into its basic elements so the plant can easily use it. Hydroponic and regular fertilizers then supply the plants with these elements.

Another difference between hydroponic and regular gardening is that growing hydroponics can be extremely complicated. Hydroponics are controlled with computers and sensors which help control everything from watering cycles to nutrient strength, and the amount of light the plants receive. However, hydroponics can also be very simple. The average home hydroponic system usually consists of a few basic parts, including a growing tray, a reservoir, a timer controlled submersible pump to water the plants, and an air pump to oxygenate the nutrient solution. Light is, of course, also required to help the hydroponic garden to grow.

There are also micro-nutrients that are required for healthy plant growth. These micro-nutrients include calcium, sulfur, magnesium, boron, cobalt, iron, copper, manganese, zinc, and molybdenum. These nutrients are the essential elements that plants need in very small amounts. Plants are likely to become sick without these trace elements and will develop all sorts of problems depending on which nutrient is missing.

The lack of micro-nutrients in food crops can mean a lack of nutrients in the food. This will result in the food not being as healthy as it could be and potentially lead people to develop health problems due to the lack of these essential elements. Any hydroponic gardener needs to use a good quality hydroponic fertilizer when they are growing plants using hydroponics.

It is also vital that the pH is controlled in both growing hydroponics and in the soil as well. Plants lose the ability to absorb different nutrients when the pH varies. The pH must be monitored during the entire growth cycle of the plants to maintain the maximum healthy uptake of nutrients. The pH of the nutrient solution will affect how well each element can pass through the root cell wall to nourish the plant. Once the gardener has properly calibrated the fertilizer concentrations and the pH of that solution, they can generally assume it will stay steady barring any unforeseen root disease.

Gardeners should always monitor their system too much rather than too little to avoid any problems. The ability to quickly and easily test and control pH in hydroponics is a major advantage over regular gardening, where testing and adjusting the pH is much more complicated and time consuming.