Which Type of Water Is Better for Plant Growth: Purified or Distilled?

How Water Works in Plants

• Water is absorbed from the roots of plants and in the stoma on the leaves. The majority comes up from the roots, which are typically in soil. Plants growing outdoors will bring up water that has minerals and vitamins as well as trace elements from the soil. Plants in pots have a bit more trouble achieving their nutrient needs because they are in a closed environment and the nutrients in the potting soil will diminish over time. This makes it necessary to provide extra food for the plant. Many of the minerals a plant needs come from the water you use.

Distilled Water

• Distilled water is pasteurized and cleaned in a steam process. It is clear of all minerals and vitamins, leaving nothing behind but the pure joined molecules of hydrogen and oxygen. Distilled water will not harm your plants and is an excellent substitute for tap water. Tap water often has such high concentrations of chlorine, it can harm plant health. Distilled water is also low in salt, which has a desiccating effect on plant cells.

Purified Water

• Plain purified water has not had a heating process applied to it but it has been run through a complex system of filters. The amount of chemicals left in the water is greatly reduced and there are still some nutrients in the water. These nutrients are necessary for plant growth and development and will allow you to rely less heavily on supplemental feeding.

Plant Needs with Distilled Water

• Distilled water will hydrate plants' cells, but it does not provide the nutrients that they need to survive. If you use distilled water as the main source of hydration, you will need to supplement it with fertilizer, unless the plants are growing in a particularly nutrient-rich soil. However, fertilizer needs to be used carefully and according to the product's instructions, otherwise it can cause a dangerous buildup of salts in the soil.