Can You Use Tap Water For Hydroponics?

Ed Wike
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How Long to Leave Tap Water in the Sun?

The water that comes out of your tap is POTABLE, but it is not always CULTURED. When it comes to growing plants, you need to determine if your water is NATURAL or PROCESSED.

Tap water can be considered NATURAL or PROCESSED depending on whether it has been treated with chlorine or other chemicals or if it has passed through a series of ponds, reservoirs, and canals.

NATURAL water is considered to have the following properties, which are suitable for a deep water culture system.

  • PH: 6.5-7.0 (should have a lower PH than the plants you are growing)
  • Free chlorine: < 0.01 ppm (a significant measure of water purity)
  • Total dissolved solids of < 500 ppm (dissolved substances in the water)
  • Nitrate concentration of < 10 ppm
  • Electrical conductivity: < 5 dS/m (conductivity is a measure of salinity)

Unfortunately, most cities use PROCESSED water in their drinking supply that has been treated with chlorine. This type of water has a slightly higher PH than the desired 6.5-7.0 and also contains higher levels of total dissolved solids.

Chloramine: Another Potential Threat

The problem is a common one. To regulate harmful bacteria in the water system, water supplies nationwide are treated with a chemical called chloramine. Unlike chlorine, chloramine is added to water at the central water facility and it remains in the water until it reaches the home tap. Due to its high chlorine levels, chloramine can pose serious problems for anything living in your hydroponic system.

As the chloramine travels through the pipes, it breaks down into free chlorine and ammonia. The free chlorine disinfects the water by such a high degree that when it reaches your hydroponic system, it is so highly concentrated as to cause burns on the leaves of your vegetable plants.

The ammonia is deadly to the roots of your plants because it converts into nitrites and eventually nitrates. A dramatic build-up of nitrates in your system can lead to toxic algae growth and root rot if your plants cannot metabolize the buildup of nitrates.

One Final Consideration: Tap Water PPM

Tap water is convenient and can sometimes be more affordable, depending on your water source. But it isn’t always the healthiest choice for your plants.

That’s because tap water usually contains chlorine, fluoride, and sometimes heavy metals.

Each of these substances can be detrimental to your plants.

Chlorine is added to our water supply to kill off harmful bacteria and prevent waterborne illnesses. It can also negatively affect the health of your plants.

Fluoride is a mineral that helps fight tooth decay. Unfortunately, it can also slow growth and reduce the vitamin content of your plants, causing issues such as nutrient deficiencies.

Heavy metals like lead, copper, and mercury are usually leached from pipes and wiring, and drilling and manufacturing. Over time, this can build up in your water supply. These metals cannot be filtered out, making tap water unsuitable for hydroponic use.

How Hard Water Affects Plants

Hydroponics, hydroponics for dummies, hydroponics marijuana. The term hydroponics seems to be floating around in many conversations and the interest in this practice of growing plants without soil is on the rise. Hydroponics, a practice that use water to grow plants has become a very popular gardening technique over the past ten years.

Many of those who have used hydroponics or plan to try it, are wondering how hard water affects plants the process of growing plants without earth.

Water hardness is a measure of the dissolved calcium and magnesium in an area's water supply. The dissolved minerals in water can interfere with the absorption of certain minerals and nutrients from the plants' roots. For instance, plants that require a lot of potassium, like bananas, may be affected by excessive amounts of dissolved minerals in the water.

Before you fertilize your hydroponically grown plants, you need to test your water to be sure that the water you're using is soft enough. If it's not, you may have to use a fertilizer that contains less potassium to prevent leaf burning. If you're using city water, it's best to buy a reverse osmosis unit or a water softener to filter your water before it goes into the nutrient solution. The most common minerals present in hard water that can negatively affect your hydroponic plants are calcium, magnesium, and iron.