Pool water is a no-no for flower pots
Question: We have a pool in our backyard and around the pool seating area we have a lot of flower pots. They're full of flowers like geraniums, petunias, spikes, ageratum and lots of other plants. My husband is fond of watering them with water from the pool. He dips the watering can in and then waters the containers because he says it's easier than pulling the hose down to the pool. I think this is bad for the plants. Last year some of the leaves turned brown around the edges. Was it because of the pool water?
Answer: Sorry, husband, but watering plants with water straight from a pool is not a good idea. Regardless of whether you have a newer pool that uses salt or one that uses chlorine to keep the water clear, water that comes directly from a pool is bad for plants.
The dissolved minerals and chemicals found in pool water can mess with a plant's ability to uptake water and/or to process nutrients. Yes, tap water contains chlorine, too, but not at the same concentration as pool water. Plus, pool water that has added algaecides and other chemicals to prevent the growth of microorganisms can cause other problems as well. The pH of pool water can also be problematic when it comes to plant health.
That being said, chlorine is volatile. So, if you only use chlorine in your pool and not any other chemicals, you can use pool water to irrigate your containers, but only if you allow the chlorine to fully dissipate prior to using it on your plants. To do this, fill open-top buckets with water from the pool and allow them to sit for 36-48 hours prior to use.
If you have a salt water pool, you may notice a hard white crust develop on the soil in your containers when your husband waters the plants. If you have terra cotta pots, the salt may build up on the outside of the pot, too. Plants watered with salt water are destined for many health issues, including leaf splotches, leaf yellowing or browning of the leaf margins, among others. Leaving salt water sit out in buckets as described above will not remedy this; in fact, as water evaporates from the sitting buckets it will concentrate the salt and make the water even more harmful to plants.
If your pool is surrounded by in-ground plants that occasionally get splashed with pool water, you'll see little to no ill effects, unless the plants there are particularly sensitive. Most common landscape plants can tolerate the chlorine and/or salt concentrations found in pool water at the low amounts caused by splashing. However, you should avoid watering in-ground plants directly from the pool, too.
Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio with Doug Oster. She is the author of several gardening books, including “Attracting Beneficial Bugs to Your Garden,” “Good Bug, Bad Bug,” and her newest title, “Container Gardening Complete.” Her website is jessicawalliser.com. Send your gardening or landscaping questions to firstname.lastname@example.org or The Good Earth, 622 Cabin Hill Drive, Greensburg, PA 15601.