Q/A #58 - TDS of Water in Our Pools

QUESTION:
I water my plants with rainwater that has a TDS reading between 7 and 20 PPM, depending from which source. Water collected under trees is higher; water collected out in the open is lower. So, I'm curious. After your plants sit, or when your medium has set for a while, what does the water in your pools test at? Mine is 30-40 PPM.
(Submitted in March 2020.)

RESPONSE BY JEFF DALLAS:
TDS means total dissolved solutes, so higher readings after your pots sit for a while means that your meter is picking up organics dissolving in the water, including leaves from trees. Dissolved organic material is of no consequence to carnivorous plants. It's dissolved minerals from underground water sources you need to pay attention to. As long as your TDS readings are below 50 before watering your plants, the water is fine to use long-term.

As for the actual TDS in our pools, I don't know. In the decades of growing Sarracenia, I never bothered measuring the TDS. I already know it's going to be high because of the dissolved organic material, which hasn't had any adverse effect on our plants. I only measure the TDS of the water when it comes out of the spigot. That's the only TDS reading that matters most to me.

• The original question and response have been edited for publication.
• With a database of thousands of questions, we will post a Q&A every few days or so.
• To search for similar posts, click on a hashtag below or use the site's search function.
• To submit a carnivorous plant question, visit Ask the Growers.