The Effects of Chlorine on Garden Health: Is Your Water System Damaging Your Plants?

If you live in a major metropolitan area and receive water from a water company, Chlorine or chloramine is likely added to the water as a disinfectant. This is excellent news because Chlorine or chloramine kills disease-causing germs like salmonella and norovirus. However, when I was shelling out money for yet another load of worm castings for my garden (worm castings contain a highly active biological mixture of bacteria), it dawned on me that I was adding bacteria to my soil and then watering it in with chlorinated water formulated to kill bacteria. Is this a sustainable practice?

What is Chlorine?

Chlorine is one of the top 10 manufactured chemicals in the United States. It is produced commercially by electrolysis of sodium chloride brine. It is used as a disinfectant and is found in many household cleaning products. It is the basis for most common bleaches.

Chloramine is a combination of Chlorine and ammonia. Many water agencies refer to chloramine as monochloramine. According to the World Health Organization, monochloramine is less effective than Chlorine in inactivating E. coli and rotaviruses.

According to the U.S. Environmental Protection Agency (EPA), chlorine levels of four parts per million or below in drinking water—whether from a private well or municipal reservoir—are acceptable from a human health standpoint.

How does Chlorine impact my plants?

The Centers for Disease Control and Prevention tell us that plants are not harmed by water treated with Chlorine. Most of us have been watering our plants with chlorinated water for years, and they survive.

How does Chlorine impact the soil?

Chlorine kills some of the microbes in your soil. Making worm tea with chlorinated water defeats the purpose of worm tea. Colorado’s state extension service tells us chlorinated drinking water may kill several microorganisms in soil or a compost pile. However, their reproduction rate is so rapid that populations rebound quickly. In one study, researchers continuously applied highly chlorinated water to the soil for 126 days. Two days after they stopped, the soil microorganism populations reached pre-treatment levels at all soil depths.

I want my plants to thrive, not just survive.

There are a few reasons why your garden looks better after a rain. One of these reasons is that your plants are receiving non-chlorinated water. I noticed that most indoor agricultural growing facilities using city water run the water through reverse osmosis units. The carbon filters remove the Chlorine. Anyone making beer or bread/pizza (yeast in water) would also want to eliminate Chlorine from their water.

The next time you water your garden, it is an excellent time to think about the chemicals in your water. You may not hurt your plants with city water, but most want beautiful, thriving gardens. We all know the value of rainwater for conservation, but considering you are getting water without Chlorine, this is another excellent reason to consider installing one this fall. I will also look into a reverse osmosis system for my house and landscape and other ways to eliminate Chlorine, and I will report back here. If you enjoyed this article, please consider subscribing or following me on Twitter @H2oTrends.