The Best Water for Your Plants


If you think plant care is only about how watered your plant is, you’re missing out.

Knowing the kind of water you should be using can be just as important in getting your plants to bloom. And it depends on a number of factors, from water hardness to pH level. 

Chlorination Level

Additives in tap water like chlorine might be beneficial for humans, but not necessarily for plants. Chlorine is often added to municipal tap water to kill contaminants and microbes, so it’s worth checking your tap water quality report – particularly if you have more sensitive plants.

While in small amounts, chlorine can be nutritious to help your plants grow, anything more than minute quantities can have a direct negative impact on your plant because the good soil bacteria gets killed. 

“In high concentrations, chloride can become toxic for the plant”, says the team at indoor farming startup Infarm.

The safest option for your plants is non-chlorinated. 

pH Level

Generally, plants thrive at a pH level of about 5.5 to 6.5, a mildly acidic water. The pH level of your water decides whether your water is acidic, basic, alkaline or neutral – all of which can determine whether your plant absorbs nutrients effectively.

If the pH is too low and therefore too acidic, most nutrients are dissolved too easily, which can actually lead up to a build-up of compounds that are not plant nutrients like aluminium. These collect in your soil and typically make the soil quality of your plant quite poor. Acidic conditions also lower the levels of nutrients that are key to plant growth, such as phosphorus, calcium magnesium and molybdenum.

If the pH is too high – meaning too alkaline – this can cause deficiencies in your plant’s ability to absorb enough of the right minerals. If your plant’s leaves become yellow between the veins, for example, this would be an iron deficiency but not necessarily from the soil lacking in iron. A high pH stops the iron in the soil being able to convert into a form the plant can absorb. As a result, a toxic level of nutrients end up sitting on your soil, unable to be absorbed and consequently harming your plants.

Hardness Level

Hardened waters typically contain large amounts of salt and bicarbonates like magnesium and calcium, whilst softened water contains lower quantities. Although too many salts and bicarbonates can be detrimental, the right amount of hard water minerals are nutritious for your plants.

Similarly, hardened waters or waters high in minerals are often softened with sodium carbonates. So soft water may actually hinder the growth of your plants due to the gradual build-up of sodium. The ideal water would be not soft and not too hard.

“It really depends on the type,” adds the team at Infarm, “but if we’re talking about potted plants, a low Electrical Conductivity (EC) water is the most ideal water for plants.” The EC of your plant measures the total dissolved salts in the plant’s soil, allowing you to see how much this influences your plant’s ability to absorb water.

Purity Level

Purifying your water through boiling or distillation has the benefit of removing a lot of harmful contaminants that could seep into your plant’s soil. However, distilled water also removes any of the healthy minerals present in water, which could consequently affect your plant’s ability to bloom. Some trace contaminants can also remain through certain filtering or purification methods.

The important aspect is to make sure the water you feed your plants has a balanced amount of minerals and salts to help keep your plant healthy and growing well.

By Lauren — Jul 31, 2020
The information contained in this article is provided for educational and informational purposes only, and should not be construed as health or nutritional advice.

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