The nutrient mixtures and growing mediums used can be very expensive. 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. Solution culture uses a nutrient solution but does not use a solid growing medium for the roots. The medium culture has a solid growing medium for the roots such as gravel, sand or a perlite culture. Hydroponic plants are grown in a number of ways, each supplying nutrient solution to the plants one way or another. If you are still unsure about starting a hydroponic garden, you can get everything you need in a little kit called a plug-and-go hydroponic gardening kit. These little kits have everything you need to get you up and running with this fascinating hobby. The typical kid includes a module for holding your plant cubes, seeds, nutrient solution and a heating pad. Many gardeners have made their dreams come true by making their living in their backyard greenhouse and selling their produce to local restaurants and markets. The potential of hydroponic culture is incredible, but commercial hydroponics in the United States was held back until hydroponic systems that were economical to build and relatively easy to operate became available in the marketplace. 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 process is the same as creating a batch of wine, beer or mead. Once the batch has stopped bubbling the fermentation process has ceased and another batch will need to be made in order to continue the production of carbon dioxide. ” In companion planting crops are intermixed with plants that act as spider mite deterrents for the primary crop. For example, marigolds may be planted between rows of herbs in a hydroponic greenhouse. Spider mites will be turned off by the smell of the marigolds and will leave the garden. Biological insect control is another method of pest management through the introduction of predator insects to eliminate spider mites.