Hydroponic plants are grown in a number of ways, each supplying nutrient solution to the plants one way or another. Hydroponics can be used to grow plants anywhere, even in your own backyard. Using hydroponics can grow anything from garden crops to flowers. Hydroponic gardening is considered to be a clean and highly effective method for growing plants. Dry ice can be used in small greenhouses, especially if a cooling effect is also desired. Dry ice, which is solid carbon dioxide, is effective when used in a well-sealed area. The ice can either be used in block form or broken down into small pieces and used a little at a time. Another method is to put the dry ice into a Styrofoam container with holes in it to slow down the rate of evaporation. Hydroponically grown plants are not immune to spider mites, but they are more pest resistant than plant grown in soil. Plants grown in hydroponics are usually healthier than soil grown plant, because hydroponic plants are fed their exact nutritional requirements. The natural preventive measures against spider mites are used in most hydroponics systems. A gardener can also buy any of the items they need for their grow room from stores specializing in hydroponic supplies. Once you have your grow room or greenhouse set up, you can decide which plants that you want to try and grow. Many people like to start with tomatoes or roses since they have many hardy varieties to choose from. In hydroponics plants are grown in a solution consisting of water and nutrients required for a particular plant, or within a system that uses a substrate or growing mix medium. 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. Hydroponics is proven to have several advantages over regular soil gardening. The growth rate on a hydroponic plant is 30 to 50% faster than a soil plant that was grown under the same conditions. The yield of the plant is also greater. There are many reasons for the drastic differences between hydroponic and soil plants.