Are You Really Sure You Want to Water Your Plants From the Tap?

Author: Anna Gershenson

Some plants may benefit from chlorinated water, due to its ability to kill unwanted bugs or microbes in the soil. However, chlorine is actually toxic and harmful to plant growth in high concentrations. It injures the plants’ roots and accumulates in the leaf tissue, causing enduring damage.

So, how much chlorine is too much chlorine? And what can we do about it given that most people water their gardens and houseplants straight from the tap, and the tap water in Virginia contains small amounts of chlorine? I have a tip for you based on research that I performed in school.

As a freshman at Fairfax High School, I participated in the school’s Science Fair for my Honors Biology class. For our project, my partner and I designed a project to test the effect of chlorine on Wisconsin Fast Plants, a type of Brassica rapa plant, developed by the University of Wisconsin as a research tool.

We grew four groups of the Wisconsin Fast Plants, from the seeds, and fed each group natural spring water with different amounts of chlorine mixed in. The first group received the water without chlorine (this was known as the control group). We watered the second group with a mixture of water and one teaspoon of chlorine, the third with 2 teaspoons of chlorine mixed with water, and the fourth with 3 teaspoons (1 tablespoon) and water. My partner and I used powdered chlorine, so before we gave each plant the mixture, we let the chlorine fully dissolve in the water. We watered the plants every two days and measured their heights during those days. We studied the plants for two weeks.

The results were significant. The images below represent the four plant groups at the end of the two weeks. 

As you can see, the group that did not receive the chlorinated water grew the most and looked very healthy. The average final height for the plants in that group was about 5.10 centimeters. 

The plants that received 1 teaspoon of chlorine grew a little bit, but looked unhealthy. The plants looked more brown than did the healthy plant. Their final average height was 1.50 centimeters. 

A small plant sprouted in the pot that got 2 teaspoons of chlorine,, but it did not grow as much as did the previous two. That group’s final height was about 1.00 centimeter. 

And finally, the plants that received 3 teaspoons of chlorine barely grew. Though it is difficult to see the plant, the calculated height of that group was about 0.50 centimeters.

It was clear that even 1 teaspoon of chlorine stunts the growth of plants and makes them lose pigment.

Now, you might be wondering: “What can we do to solve this problem? Buying natural spring water costs extra.”

Don’t worry, I have the perfect solution for you!

My mom actually familiarized me with this technique. She enjoys working in our garden and knows all sorts of tricks. When I decided to grow a vine plant in my room, my mom suggested that rather than watering them with tap water fresh out of the faucet, to begin by pouring the tap water into a plastic cup and letting it sit a couple of hours before watering the plant. Letting the water wait enables all of the chlorine to evaporate, clearing it and making it healthy and safe for the plants.

I did the controlled research to validate her advice. You don’t have to subject your plants to extra chlorine, but you can see if letting the chlorine evaporate helps your house plants and garden do better. Enjoy watering your plants chlorine-free!

Anna Gershenson is a rising senior at Fairfax High School.

This post is part of the series Creative Counsel from Students in the Time of COVID-19. Do you know students with research to report on the natural world? Encourage them to direct their proposals to after reading the instructions in the link above.

Nature in a Time of Crisis: A Conversation with Melanie Choukas-Bradley

Jun 12, 2020, 1:00 PM

Join Capital Nature and Park Rx America for a timely discussion with naturalist and author Melanie Choukas-Bradley. Inspired by her new book: Resilience: Connecting with Nature in a Time of Crisis, the program will explore how a relationship with nature can nurture and support our wellbeing during COVID-19 and other crisis times.

Melanie will share highlights from her interviews with aspiring and seasoned naturalists across the country. She will offer practical advice for: “how to establish a wild home; how to develop nature connection as a mindfulness practice such as integrating meditation, yoga and tai chi; how to become a backyard naturalist and weave nature appreciation and study into your home schooling and how to develop new ways of seeing and being in the world.” We will also hear from DC-area residents who have found new ways to engage with nature for their own wellbeing and the wellbeing of their families.

This event is co-hosted with Park Rx America. We invite you to listen in and join us for the conversation!

Register here

Face the Wolf

Jerry Nissley

“I scarcely know where to begin…”: The opening line in Jack London’s, Sea-Wolf. This 1904 story develops around a self-indulged, self-professed gentleman of the times, Humphrey van Weyden, who decides to visit a relative across the bay. The fateful day he boards the ferry from Sausalito to San Francisco, the bay is shrouded in dense, preternatural fog. So much so that boats could only navigate using compass, speed, and distance –“a mathematical certainty“, right? Ergo the inevitable transpires–in spite of, or perhaps because of, the cacophony of navigational bell buoys and ship’s fog horns, the ferry is suddenly struck amidships by a steam schooner crawling in against the tide.

Chaos prevails and young Humphrey barely has time to secure his life jacket before he jumps/falls from the fast sinking ferry into the frigid waters of the bay. Hypothermia is a cruel, uncaring beast, and the weak, water-logged human bobber is quickly carried towards the Golden Gate by fast-moving current caused by the ebbing tide. Despair and hopelessness lead to delirium and unconsciousness; yet at the last possible moment Humphrey is plucked from the water by a passing sealing schooner, the Ghost, on its way to Japan. The Ghost’s intractable captain, Wolf Larsen, does not return Humphrey to shore but instead indentures him for the duration of the voyage.

I love classical symbolism. I recalled that story while I was on a four-hour kayak trip the Monday before our current executive order to lock-down. To me the opening scene in Sea-Wolf is analogous to the Corona-virus situation we are in today. Our carefree lives have been hit amidships by a runaway schooner-virus; knocked into treacherous waters and after floundering for a time, we now find ourselves confined to our boat-houses under incommodious restrictions. Are we all now symbolically Humphrey van Weyden indentured by a viral personification of Wolf Larsen? Will we all be better versions of ourselves once we endure this indentured servitude?

I scarcely know how to continue… for alas, I did not sit down to write specifically about Humphrey van Weyden or Wolf Larsen. I sat down to write about how through all of the prevailing current events, spring continues to flourish and how I am encouraged by Nature’s example of fortitude. An example worth emulating. 

Prior to restrictions, I was able to visit both Huntley Meadows Park (HMP) and Mason Neck State Park (MNSP) several times as a volunteer and as a casual visitor/user. At HMP I observed the hoodies and the woodies, the pins and the shovelers, the muskrats, osprey, snake-heads, spotted salamanders, assorted reptiles and migrating birds continue the cycle of life directly up in the face of the “Wolf“. 

Wood Duck

Kayaking at Mason Neck State Park, I observed that emergent vegetation is starting to show through the mud in Kane’s Creek. Spatterdock, cattails, pickerel weed and swamp mallow are starting to form along the water’s edge. Hopefully kayak tours will start up again in the summer months. Whether that happens or not, osprey, eagles, red winged blackbirds and beaver continue nesting/lodging rituals as if they plan to stay another year. I floated up to copious painted turtles adorning the logs like jewels, soaking in vitamin D. In the coves I sensed the sibilant swirl of pre-spawn fish around fallen trees in search of food and nesting sites. They, too, are planning to stay for the year.

Beaver Lodge

Oh yes indeed — our kindred spirits, Flora and Fauna, embrace us. They show us there is a great deal of beauty and emerging hope all around. Perhaps we need to use our God-given senses to discern this — hear and distinguish the cries and calls, taste the Coral honeysuckle, smell the Sweetspire, see and perceive changing patterns, touch the morning mist. We need to be smart, stay safe and get through our “indentured servitude”. Our short-term restrictions do not even compare to Mr. van Weyden’s protracted ordeal and he, “… discovered his own legs and learned to stand on them“.

As a closing solicitude, consider Mr. van Weyden’s own contemplation as the crew emerged from a particularly trying ordeal at sea, “One thing I was beginning to feel, and that was I could never again be quite the same man I had been. While my hope and faith in human life still survived Wolf Larsen’s destructive criticism, he had nevertheless been the cause of change in minor matters. I had learned to look more closely at life as it was lived… to emerge from the realm of mind and idea and to place certain values on the concrete and objective phases of existence.