Plants need three main elements in order to grow: water, sunlight and carbon dioxide. Water is important to plants for various reasons, such as transporting gases during photosynthesis and creating glucose needed for energy. Plants can also grow when watered with other liquids.
Different plants grow with different liquids. Some plants are better able to grow in liquids other than water, while other plants react badly to liquids that aren't 100 percent water.
Watering plants with different liquids provides the plants with not only the water needed for growth and other functions, but it provides the plant with other gases and nutrients that either support growth. For example, watering Baby's Tears plants with carbonated water provides plants with macronutrients, such as carbon, potassium and sulfur, according to the University of Colorado at Boulder. Watering plants with tea is beneficial for plants fed water high in salt, since the acid in the tea neutralizes the salt. Hydrogen peroxide can be sprayed on plants to provide supplemental oxygen and prevent mold and fungus growth in the soil.
Giving plants other liquids, such as milk, is potentially harmful. Tomato plants, for example, can't absorb most of the nutrients in milk, so if you're watering tomato plants with milk only, the plants will eventually die. Milk is also known to cause bacterial growth in soil, due to the abundance of carbohydrates in the milk.