Hydroponics is a gardening philosophy that allows you to get higher yields than traditional gardening does, and it takes up less space. Because the roots get the nutrients they need directly from a solution and a frame holds up the plant, the roots do not need to be as large or have as much structure. One of the benefits of a do-it-yourself approach to hydroponics is that you can experiment with the design and the techniques and make adjustments where you see a need, rather than having to rely on a kit from a manufacturer.
The six basic categories of hydroponics are Nutrient Film Technique, Water Culture, Wick, Ebb & Flow (Flood & Drain), Drip and Aeroponics. The Wick and Ebb & Flow techniques are passive and generally much simpler to implement. The others can require sophisticated frames and pumping systems, and they are dependent on electricity and the presence of the gardener. The Wick technique can hold several plants while taking up only a few feet in front of a window in an apartment, so it is an appealing choice for hydroponic gardeners with limited space.
Many sites publish free hydroponics plans, so you can build your own system. HydroponicsOnline.com offers free plans with pictures to help you visualize your system and how it works. Homemade Hydroponics also offers a number of free ideas to help you get started. Make sure you look through all of the available options, because a more expensive setup is not necessarily better. You can make many systems on a small scale with items you may already have in your house.
You can experiment with the passive hydroponic techniques using items you probably already have in your home before you decide on a large scale system. For systems that require a pump, you can still build a small scale version before you take on a large crop, but you may have to invest in a lot of PVC piping, as well as a pump and a tub for a nutrient reservoir. You can make your hydroponics garden for less than it would cost to buy one, but there is more risk in investing in those materials if you have never tried hydroponics before.