Water: To Treat or Not to Treat

That is the age old question. Let's explore water hardness, pH, and fertilization practices. When it comes to plant care, water quality is often overlooked. However, factors like water hardness and pH can significantly impact plant health. While treating water isn't mandatory, understanding these elements can help maintain the vitality of your plants.

Understanding Water Hardness

Water hardness refers to the concentration of dissolved minerals, primarily calcium and magnesium. The U.S. Geological Survey classifies water hardness as follows:([Wikipedia][1])

Soft: 0–60 ppm
Moderately Hard: 61–120 ppm
Hard: 121–180 ppm
Very Hard: >180 ppm([Wikipedia][1], [Reddit][2])

In the United States, water hardness varies by region. For instance, Arizona's water hardness averages around 230 ppm, classifying it as very hard, while Ohio's water hardness is approximately 47 ppm, considered slightly soft .([Best Water Filter System][3])

Impact of Hard Water on Plants

Hard water can affect plants in several ways:([Aquazona - Tucson][4])

Nutrient Uptake Interference: Excess calcium and magnesium can hinder the absorption of other essential nutrients like potassium and iron, leading to deficiencies .([Rayne Water][5])

Altered Soil pH: Hard water tends to increase soil alkalinity, which can limit nutrient availability, especially iron, resulting in chlorosis (yellowing leaves) .([Atami][6])

Salt Accumulation: Regular use of hard water can lead to salt buildup in the soil, affecting root health and water absorption .([Atami][6])

Fun Fact: Hydrangea flower color can change based on soil pH. Acidic soils (pH < 6) produce blue flowers, while alkaline soils (pH > 7) result in pink blooms .([Rain Harvest][7])

The Role of Water pH

Water pH affects nutrient solubility and availability. Most plants prefer a slightly acidic to neutral pH (5.5–6.5) .([Atami][6])

High pH (Alkaline Water): Can cause micronutrient deficiencies, particularly iron, leading to chlorosis (the loss of normal green coloration in the plants leaves).

Low pH (Acidic Water): May increase the availability of certain nutrients but can also lead to toxicity if not monitored.

It's important to test your water's pH and adjust as necessary to maintain optimal plant health.

To Treat or Not to Treat?

While treating water isn't essential for all plants, it can be beneficial, especially in areas with hard water. Options include:

Using Rainwater: Naturally soft and slightly acidic, rainwater is ideal for most plants.

Filtering Tap Water: Removes excess minerals and chlorine.

Using Fish Tank Water: A lot of people who are into the plant hobby tend to be into keeping fish as well. If you so happen to have a fish tank, you could use the water that you remove during water changes as your fertilizer. The aquarium water is already treated and has nutrients from the fish excrement. 

Avoiding Sodium (Na)-Based Softeners: These can harm plants; opt for potassium (K)-based softeners if needed .([Aquazona - Tucson][4])

Remember, the necessity of treating water depends on your local water quality and the specific needs of your plants.

Fertilizing with Every Watering?

Fertilization practices vary among gardeners. Some believe that using natural fertilizers allows for fertilizing with every watering. Once a suitable formula is established, even artificial fertilizers can be used regularly. However, it's crucial to monitor plant response and adjust accordingly to prevent nutrient buildup or deficiencies.

*Fun Fact*: Eggshells, rich in calcium carbonate, can be used as a natural fertilizer to strengthen plant cell walls .([Beaumont Enterprise][8]) The best way to use them, would be to crush them up and sprinkle throughout your soil during repots. If it's not quite time for a repot, you can always sprinkle the egg shell dust on top, and water it in. 

Conclusion

While not mandatory, treating your plant water can enhance plant health, especially in regions with hard water or high pH levels. Regular testing and adjustments can lead to more vibrant and resilient plants. As with all gardening practices, observe your plants and tailor your approach to their specific needs.

Sources:

[1]: https://en.wikipedia.org/wiki/Hard_water "Hard water"
[2]: https://www.reddit.com/r/springfieldMO/comments/oxe6ed "Water Hardness at Springfield, MO"
[3]: https://waterfilters.systems/water-hardness-by-zip-code "Water Hardness By Zip Code & State Name in USA 2025"
[4]: https://www.aquazonatucson.com/water-softeners-filters/water-softeners/is-hard-water-bad-for-plants "Is Hard Water Bad For Plants? | AquaZona: Kinetico of Tucson"
[5]: https://www.raynewater.com/blog/is-hard-water-bad-for-plants "Is Hard Water Bad for Plants? - Rayne Water"
[6]: https://atami.com/usa/blog/cultivation/hard-water-vs-soft-water-which-one-is-the-best-for-watering-your-plants "Hard vs Soft Water: Which is Best for Watering Your Plants?"
[7]: https://www.rainharvest.co.za/2010/06/effects-of-rainwater-and-water-ph-on-plant-growth "Effects of Rainwater and Water pH on Plant Growth | Rain Harvest"
[8]: https://www.beaumontenterprise.com/entertainment/article/spring-gardening-boost-soil-health-better-plant-20237919.php "Should you be using egg shells and coffee grounds in your garden?"