Water quality is central to a hydroponics system.

Hydroponic Water Care Tips

by Cindy Quarters

Water is the heart of a hydroponic system, and the success or failure of your plants depends on water quality. You can use tap water in your hydroponic system, but poor-quality water it will impact how well your plants grow. Pay some attention to your water and what it needs before you start growing to get the best results from your hydroponic system.

pH Balance

The pH of water is a measure of how acid or alkaline it is, which affects the plants’ ability to absorb nutrients. Plants generally thrive in a pH of about 5.5 to 6.0, though some plants may have slightly different pH requirements. Purchase a water testing kit from a hydroponics supplier and check the pH of your water before using it in your system. Use pH adjusting chemicals included with many such kits or purchase them separately to adjust the pH as necessary.

Nutrient Balance

The needs of plants in a hydroponic system change constantly as they grow and enter different stages of life. This means that the nutrients in the system get depleted at different rates, and there’s no good way to balance the nutrients by replacing only what’s been used up. The best way to maintain proper nutrient balance in a hydroponic system is to completely replace the water and the nutrients every week or two. How often you change it depends on how many plants you have, the kind of plants you have and how big they are.


Hydroponic flushing involves replacing the system’s nutrient solution with plain water and using it in the system for anywhere from a few hours up to a week. The process benefits both the plants and the system in general by removing the potentially harmful buildup of salts and minerals from the plants, media, tank, hoses and pump. To flush, drain the system, replace the nutrients with water and run the pump for a full day. Drain the system again and wipe it down before adding fresh nutrient solution.

Water Quality

The overall water quality is affected by what is present in the way of naturally occurring solids. Common chemicals in tap water include iron, sulfur, salt, calcium, magnesium and various types of carbonates that can cause the water to be hard. Hard water itself is not necessarily bad, but it may impact the type of nutrient solution you use in your system. A water-quality test kit from a hydroponics supplier can help you to determine what solids are present in your water and what nutrients to use.

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