How to Soften Hard Water for General Hydroponics

Hydroponics gardening

Hydroponics is growing plants without soil. This is a method is often used in environments with little growing room, such as apartments or areas with little water, such as the desert. A big problem in any area is the mix of nutrients found in the growing water. With a nutrient or chemical imbalance you will have low-yielding plants or poor plant performance. Hard water needs to be addressed for optimum growth.

Things You'll Need

• Liquid soap
• Sodium bicarbonate (baking soda)
• pH Test Kit

Instructions

1. Take an 8 oz. sample of water used for growing hydroponic plants. This sample will be used to determine the hardness of the water.

2. Place one drop of liquid soap into the water sample at a time. If no suds (soap bubbles) are created in the water sample, keep adding one drop at a time until suds appear. Five drops of liquid soap indicate hard water. Very hard water requires 10 or more drops of soap. Very hard water should get a professional determination of more accurate levels.

3. Take second 8 oz. ounce sample of hydroponic water to a local water treatment company, which will usually test it for free. The company will inform you of the parts per million (ppm) of calcium and magnesium in your sample.

4. Add 1 tbsp. of baking soda (sodium bicarbonate) per 5 gallons of water to lower the levels of calcium and magnesium in the hydroponic water. More baking soda may be needed to achieve desired softness of water.

5. Test pH for acidic/alkaline levels until pH level is within desired range. Add or reduce baking soda, as necessary to achieve a pH of 7.0.

6. Adjust water levels in the hydroponic garden to counteract increases in salt level in the water, due to using baking soda to soften the water.

Tips & Warnings

• Hardness of water (ppm of calcium and magnesium found in the water) as classified by the U.S. Department of the Interior and the Water Quality Association is as follows: soft: 0.0 to 17.1ppm; slightly hard: 17.1 to 60.0 ppm; moderately hard: 60.0 to 120.0 ppm; hard:120.0 to 180.0 ppm; very hard: 180.0ppm or more. A reverse osmosis system will filter out the minerals to give you pure water. Then, you can add the nutrients you need to grow the type of plants you wish in your hydroponics system. When testing for pH, remember that acidic water is below 7 and alkaline water is above 7.

• Adding too much baking soda can result in a higher phosphate level. This can cause a general nutrient imbalance that needs to be watched closely.

Resources

• Read this Article in Spanish
• U.S. Department of the Interior and the Water Quality Association