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. The run off from growing plants in pots is the best place to measure the pH level. The protein and enzyme molecules in a plant are structured in very specific shapes in order to catalyze a chemical reaction to build the plant cells. The need reactant molecules to fit precisely into their gaps so all of the negative and positive charges have to line up exactly. Other ways to protect your hydroponic produce against spider mites include using non-toxic yellow sticky cards. The cards are useful for monitoring spider mites and many other small bugs. 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. Small grow rooms for the beginning hydroponic gardener are usually slightly larger than a closet and can be completely installed in under an hour. The cost ranges from several hundred dollars to over $500, depending on the add-ons that you think you will need. A small greenhouse can cost considerably more because you will need to either include a cement floor and drainage system or lay other types of flooring such as gravel before you build the greenhouse itself. Hydroponic gardening is an exciting field that offers solutions to several problems faced in the world of food production. For impoverished people who live in a terrain or climate inhospitable to agriculture, hydroponics offers a means of growing food. In areas where food is traditionally produced, but where fields are over crowded or stripped of their nutrients, hydroponics is a way food can be produced using a minimum of space and resources. There are five ways that you can increase the level of carbon dioxide in your greenhouse to increase plant growth. First, the burning hydrocarbon fuels will create carbon dioxide gas. Second, the use of dry ice can aid in the production of this gas. Third, fermentation of organic materials creates carbon dioxide.