Hydroponic gardening, or gardening without soil, is not a new phenomenon. In fact, some forms of gardening that could be considered hydroponic date back to the ancient Egyptians. Today, hydroponic systems are commonly used in commercial greenhouses and research facilities. Although hydroponics has been around since the Pharaohs, it is the newer advancements in hydroponic system technologies, an increased understanding of plant physiology and innovative hydroponic nutrients that have finally made hydroponic gardening practical for the hobbyist greenhouse grower. After all, most hobbyist growers stand to gain the same multitude of benefits offered by hydroponic gardening as the commercial growers.
Of all the benefits hydroponic gardening offers, the increased speed at which the plants grow is the most noticeable. The increase in the rate of growth was definitely the first thing I noticed when I experimented with various hydroponic systems. As you can imagine faster growth rates lead to bigger plants and larger yields. Faster growth really means that the plant is able to process light (photosynthesis) more quickly. But how does growing without soil allow the plants to increase the rate of photosynthesis?
Photosynthesis is a chemical reaction that can be broken down into a chemical equation. As horticulturists, we manipulate portions of this equation (water, supplemental nutrition, CO2 enrichment, etc.) which each affect the end result. When gardening in a greenhouse the light energy is supplied by the sun and is not going to be the limiting factor in the rate at which photosynthesis can occur. Instead, the limiting factors are the plant’s environmental conditions, including the availability of essential elements. By manipulating the available nutrients and the available oxygen in the plant’s root zone hydroponic growers are able to increase the rate that photosynthesis occurs their gardens.
In a hydroponic system the plants are grown without soil so the nutrients must be provided directly to the plant’s root mass via the nutrient solution. In nature, nutrients are not provided in such a direct manner. In nature, a series of synergistic relationships between microorganisms, enzymes and the plant take place in order to break down organic matter into usable nutrients. Hydroponic nutrients bypass most of this process because the minerals are already broken down into a form that is readily available for plant absorption. Synthetic or chemical fertilizers are comprised of a combination of the plant’s essential elements in a readily available form. The readily available nutrients are a key reason why hydroponic systems can produce such fast growth.
An increased rate of oxygen to the plant’s root zone helps to increase root growth and nutrient absorption. Almost every hydroponic system utilizes some sort of direct injection of air into the nutrient reservoir or into the plant’s root zone. Many of the newest innovations in hydroponic system designs have one common goal: to maximize the air (oxygen) ratio in the plant’s root zone. Aeroponic hydroponic systems, which use sprayer heads to mist a nutrient solution over roots that are suspended in air, are probably the best example of this phenomenon. Other innovative systems utilize even smaller water droplets (fog systems) to ensure the maximum amount of oxygen is available to the plant’s root zone at all times. The combination of increased oxygen to the roots and nutrients that are ready for absorption give hydroponic gardening the speed of growth sought after by so many growers.
Besides the increased rate of growth there are many other benefits of hydroponic gardening that are intriguing to the hobbyist greenhouse grower. Some of the following advantages may be reason enough for a hobbyist to experiment with a hydroponic system in his or her garden.
If you enjoy being in control you’ll love growing hydroponically. This is because in a hydroponic system the grower is literally in control of every variable. Water, nutrients, oxygen, nutrient solution temperature, etc. are all completely controlled by the gardener. Fully automated greenhouses have control over the plant’s environment. Hydroponics add another element of control since the gardener determines what, when and how nutrition is directed into the plant. Nutrient monitors make it fairly easy to determine the nutrient concentration at any given time in a hydroponic system. Specific nutrients can be tailored for specific crops and/or replenished as needed throughout the life cycle of the plant. Most hydroponic systems offer the advantage of quick nutrient changes and flushing if there is a nutrient lockout or other problem in the solution. This can be a huge advantage over soil containers that tend to hold on to excess salts and can require heavy leaching when toxic salt build up occurs.
Hydroponic gardening simply saves space. This can be advantageous to a lot of hobby greenhouse growers who have a limited amount of room. Because nutrients can be supplied directly to the root mass the planting containers in a hydroponic system can be much smaller than traditional soil containers that hold equivalent sized plants. The nutrient reservoir can also be stored outside the growing area to create even more floor space in the greenhouse. Hydroponic systems are often customized in order to save space both vertically and horizontally.
Hydroponic gardening generally produces bigger yields, attributed to the increased rate of growth. Usually the faster a plant can grow, the bigger it can get which normally leads to larger yields. The other yield-affecting aspect related to the speed of growth is the rate at which the plant reaches maturity. The faster some plants grow, the faster they will produce fruits or vegetables. If the plant is quickly producing fruits or vegetables, the grower will be able to harvest those fruits or vegetables for a longer period of time. This is why hydroponic gardening can be especially advantageous in regions with short growing seasons. Just as greenhouses help to lengthen the growing season for the horticulturists, hydroponics can help some plants reach maturity more quickly to ensure the highest yield for the gardener.
With its increased control over nutrition and oxygen it only makes sense that hydroponic gardening would be a good fit for year-round gardening applications. Hydroponics allows gardeners to tailor nutrients in such a way that would never be found naturally in soil, especially during the off season. Many year-round gardeners who already have much invested in their greenhouses in regard to environmental control naturally turn to hydroponic systems for the increased control and growth.
Hydroponic gardening offers some environmental benefits as well. Because many hydroponic systems utilize a re-circulating design a fraction of the water is used compared to traditional agriculture. The re-circulated solution contains the nutrients which can be recycled for periods up to two weeks before replenishment is needed. This is a huge savings over traditional soil fertilization which is used once and turned to waste. On the large scale, hydroponics also offer some environmental benefits over conventional methods. Hydroponics require less water, land and herbicides and pesticides than conventional farming. The importance of these factors are increasing as our world population grows and the demand for food production increases with it. Hydroponic farming may just be one of the most practical solutions to the continual problems of potential land and water pollution.
The innovative products now available to the hobbyist horticulturist are reason enough for all gardeners to, at the very least, experiment with hydroponics. From the propagation of cuttings to advanced auto-feeding systems for orchids there is a hydroponic system for virtually every garden and gardener. The heightened ability to share information in today’s high-tech world offers an array of homemade, do-it-yourself hydroponic projects; from commercial set-ups to simple window sill systems. Many of the hydroponic plans available on the internet can be built for very minimal cost which gives a further incentive for experimentation. Hydroponics can be a new, fun element for all hobbyist greenhouse growers looking to expand their knowledge in plant physiology and supercharge the growth of their gardens.
Eric Hopper resides in Michigan’s beautiful Upper Peninsula where he enjoys gardening and pursuing sustainability. He is a Garden & Greenhouse contributing editor and may be contacted at Ehop@GardenAndGreenhouse.net.