Plants need light, air and nutrients to thrive. They derive their nutrients from soil or, in hydroponics, nutrient-rich water. In soil gardens, you need to water the garden frequently so the good bacteria, fungi and microbes can add nutrients to the soil for the plants to use. Plants also need water for cellular function. The type of water used, both in soil gardening and in hydroponics, can affect plant growth.
Too much water in a soil garden can drown the roots of a plant. Too little water and the plants cannot draw enough oxygen from the soil to "breathe". The basic way to tell if your soil garden needs water is to stick your finger into the soil. If you feel damp soil, wait a day. If the soil feels dry, water the garden. In hydroponics, if the water level is too low in your system, you need to add water so the plant roots can draw their nutrients.
Water aids in transporting nutrients into plants via their roots. It also provides support on the cellular level; without water, plants wilt. But if the water is too acidic or too alkaline, plants may be unable to properly process the water for use.
Water with equal parts acid and alkaline is considered to be neutral, or have a pH balance of 7.0. When water is more acidic, that number goes below seven. For water that is more alkaline, the number goes above seven. The pH balance of water affects the acid and alkaline content of soil. If water is too acidic, calcium, magnesium and potassium levels are reduced. Calcium is required for cell growth, magnesium for chlorophyll formation and potassium for synthesizing proteins. If water is too alkaline, calcium builds up, effectively cutting off the flow of nutrients to plants' roots.
Should the water you use for your plants have a perfectly balanced pH of seven? Not necessarily. Both soil and water have a pH balance, and in soil gardening, you need to reach the right pH balance for the plants you grow. Most herbs and vegetables prefer more acidic growing conditions, with a pH of between 5.5 and 6.5. The pH balance of your water will affect the pH balance of your soil, ultimately affecting the growth and health of your plants.
In both soil gardening and hydroponics, the pH balance of the water you use for your plants is significant. Whether you use tap water, water from the hose or distilled water, you need to check the pH balance before adding it to your garden for your plants. In soil gardening, check the pH of your soil, as well, and amend the soil as needed to reach an optimum balance for your plants. In hydroponics gardening, check the pH balance after adding nutrients, as well, and then amend the water. There are products available for adjusting the pH of water in hydroponics systems.