What water is best for hydroponic systems?
Written by
Olivia Mitchell
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.The quality of the water has a significant impact on whether or not hydroponic grows are successful. Water filtered through reverse osmosis with 0-50 ppm total dissolved solids provides the cleanest base nutrients available. This prevents strife between the minerals in the water that would otherwise inhibit the plants' access to such essential minerals. The plants rely on pure water to obtain these important minerals.
Ideal Water Characteristics
- Total Dissolved Solids (TDS) below 50 ppm
- pH between 6.0-7.0 before nutrient mixing
- Chlorine/chloramine levels at 0 ppm
- Calcium hardness under 50 mg/L
Preparation Protocols
- Filter rainwater through activated carbon systems
- Dechlorinate tap water with 24-hour aeration
- Test EC and pH before each reservoir change
- Pre-heat/cool water to 65-72°F (18-22°C)
Contaminant Risks
- Heavy metals from industrial areas bind nutrients
- Bacterial pathogens in untreated rainwater
- Pesticides in agricultural runoff sources
- Sodium accumulation from water softeners
My first inkling of the importance of water came when I lost my basil crops due to contaminated well water supply. The calcium in the water was locked out, as was the magnesium, although I supplied plenty of nutrients. I always test and check all water supplies before using them. With a pure foundation of water, your plants, of course, show immediate improvement.
Maintain good water quality throughout the plant's life cycle. You should have inline filters in systems that utilize recirculation. Measure the EC shifts that indicate a change in the amount of minerals present. Replace 30% of the reservoir water every week to prevent the buildup of toxins. Effective water treatment eliminates many common failures in hydroponics.
Although more expensive to install, reverse osmosis systems are the best option as they remove 99% of contaminants and perfectly preserve mineral neutrality. If you are working commercially and even crop consistency matters, RO is an indispensable system.
Read the full article: Hydroponic Nutrient Solutions: The Complete Guide
