Passive systems may also incorporate any number of gadgets. These systems try not to use pumps and may rely on the use of a wicking agent to draw nutrients to the roots. Media based systems use some form of growing medium. Some of the more popular media based systems include ebb and flow system; run to waste system, drip feed system, and bottom feed system. While research is happening to try and bring the costs down, and there are some promising leads, like the field of aquaponics, hydroponics is currently financially prohibitive for some. There is a common misconception that hydroponics produces organic food. While it is possible to grow organic food through hydroponics, this is the exception and not the rule. The natural conditions available outdoors in the summer make it a perfect time to experiment with the various types of hydroponic cultivation. Annual flowers, fruit, herbs, and vegetables do exceptionally well with hydroponics. With hydroponics, important growing factors such as light, temperature, and humidity can be controlled. Since carbon dioxide is heavier than air it must be placed above the plants in order for it to drift down and surround the plants. Fermentation is another way to create more carbon dioxide in your hydroponic greenhouse. This method is easy to accomplish with few materials – corn sugar, brewer’s yeast, water, a small bottle and a larger container such as a garbage bag or large glass jug. The bright yellow color will attract the spider mites where they will adhere to the sticky surface. The yellow cards are best for preventing the infestations of spider mites, but can’t act alone in eliminating them. It’s best to identify spider mites before their infestation grows too large, eliminating the spider mites with early detection will save your hydroponically grown produce. There are several hydroponics techniques and systems that exist for producing plant crops. Hydroponics systems include the nutrient film technique, aeroponics, and the aeration technique. In the aeroponics method plants are anchored using screens, rigid pipes, or films. The required nutrients are mixed into the plants’ water supply artificially.