There are many methods of growing plants in a hydroponics garden (see article on Hydroponics Gardening. Kits are available for purchase that supply all the equipment necessary to get started or you can build the system from scratch. Either way, there are basic components like lights, growing media, nutrient solution and ongoing maintenance that require some education in order to make informed decisions.
Plants in an indoor environment require full spectrum light that closely mimics the sun. Fluorescent lights do not provide a full spectrum of light, but can be used to supplement natural light or grow foliage plants. Vegetables and flowering plant need much better light. Metal halide lights were developed to come as close as possible to sunlight by having a wide spectrum of light. They emit more blue light, which is good for propagation and vegetative growth. High-pressure sodium lights emit more of the red/orange area of the spectrum and while they do not have as broad a spectrum as metal halide lights, they last longer, burn brighter and are more energy efficient. The best results are obtained by using a combination of both lights because the blue/violet and red/orange segments of visible light are the most important for photosynthesis and chlorophyll production. Using light movers and reflectors will also greatly improve the efficiency of these lights. A good safety tip is to always wear sunglasses when working near high intensity discharge (HID) grow lights.
The growing medium can be made from sand, gravel, bark, polyurethane foam, coconut fiber, perlite and vermiculite. All of these will work, but the most commonly used mediums are rockwool and expanded clay. Rockwool is made by spinning melted rock into fine threads that are pressed into loosely woven sheets. These sheets can be cut into cubes, blocks or slabs. It has the advantage of holding large quantities of water and still providing excellent air circulation around the roots. Heating clay in a kiln until it expands like popcorn makes expanded clay or Hydroton. This substance provides excellent air circulation, is ph neutral and does not compact over time.
A nutrient solution should be water soluble with minimal or no residue and changed every week or two. Using one third of the dose of regular fertilizer could make a simple nutrient solution, but it is easier to use a readymade formula. A premixed hydroponics nutrient solution will have all the essential nutrients in the proper proportions, which means it is well balanced. It will contain just enough of an element to prevent a deficiency while avoiding a toxic level. It is important to monitor the strength of a nutrient solution by testing the electrical conductivity or EC level. This level can be determined with the use of a conductivity meter. This is important because a high EC means vegetative growth at the expense of flowers and fruit.
Maintaining a hydroponics garden is much less time consuming than a garden in the soil, but there are still a few chores. Check the garden daily if possible to make sure all the working parts are functioning correctly. Observe the plants closely, if there is a problem with the system it will first show up in the health of the plants. Monitor the pH to make sure it is in the 6 to 6.5 ranges, some plants can adapt to levels above or below this range, but this is a good target for most plants. A pH reading in the proper range will ensure that the nutrition in the nutrient solution is available for the plants to absorb. Circulate the nutrient solution everyday (if done manually) and top off the water level as evaporation occurs. Sterilize all parts of the unit between each new planting and keep the area around the hydroponics garden clean. It is also helpful to keep a notebook handy to record planting dates, schedule of when solution is applied and changed. Jot down any problems that develop and how they were dealt with and if those efforts were successful. This information will allow you see a pattern of what works well and can help with any problems that might occur in the future. After you have experienced some success with hydroponics, let other people know. Firsthand knowledge is a great teacher.