The soil in which plants grow provides nutrients and water in addition to structural support for the plants' roots. In hydroponic systems, the plant is grown in an inorganic growing medium or water. Instead of drawing nutrition from the earth, the hydroponic gardener provides a nutrient solution. Hydroponics offer one way for gardeners to grow indoors, year-round.
Throughout history, people have dabbled with ways to grow plants without soil. As Hydroponics Online points out, the occurrence of hanging and water gardens mentioned throughout history suggest hydroponics. Dr. Merle H. Jensen of the University of Arizona's Controlled Environment Agricultural Center states that, in 1699, a horticulturist successfully grew mint plants without soil. Interest in hydroponics burgeoned in the 20th century as new technology made profitable indoor growing a reality.
There are two basic types of hydroponic systems: liquid and aggregate. In liquid systems or water culture, plant roots grow directly into a nutritive liquid solution without any additional solid support. Aggregate systems provide an inorganic growing medium that supports the roots similarly to soil while periodic flushing with a nutritive solution meets the plant's nutritional needs.
Before setting up a hydroponic garden, consider the amount of time and money you want to spend, as well as the quality of environment you are able to provide. As Hydroponics Online points out, many plants require at least six hours of full sun per day. If you can't provide your plants access to enough sunlight, you'll need to supplement with artificial lighting, which, depending on the type and amount required, can be costly. It's possible to build inexpensive hydroponic systems, but there's a trade-off in labor and you must manually flood the system multiple times per day. Automated hydroponic systems can cost from just under $100 to more than over $400, but often provide limited capacity for growing.
Hydroponic gardens don't grow weeds and aren't susceptible to soil-borne diseases. Pest infestations are rare and easily controlled when they occur. Because of this, hydroponic gardens require neither pesticides nor synthetic fertilizers, both of which can harm the environment. Furthermore, according to the website Hydroponics Simplified, the skilled hydroponic gardener can get three times the yield than from a traditional vegetable garden.
As Dr. Jensen rather bluntly states, "Hydroponic culture is an inherently attractive, often oversimplified technology, which is far easier to promote than to sustain." Plants are not meant to grow in hydroponic systems. The gardener must account for and control every variable affecting plant growth, which can prove labor-intensive, costly and confusing for many people.