Would you be surprised to learn that plants don’t need soft water – hard water provides calcium and magnesium, two nutrients needed by plants – a water softener will remove those molecules and replace them with sodium ions. Though minimal ( 30 mg per gallon, NSF 44), those ions will build up over time. It is not much considering an 8 oz glass of milk contains about120 mg. With time watering your plants with soft water will build up the sodium content in your soil. Sodium buildup in your soil can be corrected with lime or gypsum; if you suspect salty soil consider a lab test to figure out a plan of action. Some water softeners have a feature that removes chlorine from the water. So, on the one hand, you are removing the hardness, something that plants need, but on the other, you also remove chlorine, something the soil doesn’t need because it kills bacteria. So what should you do if you want soft water in your home but safe water for your plants? Here are some options to consider when getting your water softener installed.
Pretty Good Option:
Bypass the waterline before your water softener- You can have a water softener installed to protect your home and run a water line to your irrigation system for your plants. You can enjoy soft water in your home and give the plants in your yard city water. If you can’t bypass the waterline, bypass your softener when watering your plants.
Use a carbon bock filter for water for your plants – Chlorine is good at killing bacteria, and it doesn’t discriminate between the good bacteria in your soil and the water-borne pathogens. A carbon filter will remove the chlorine from your water before it ever reaches your plants, eliminating the chance of killing off any good bacteria. In addition, chlorine is not directly toxic to plants. At under 5 ppm in El Paso, we are at around 2 ppm.
Use rainwater and carbon filtered water – we live in El Paso and get about 10 inches of rain per year, 1.5 inches during the monsoon season, so if you can somehow capture that rainwater with a rainwater harvesting system, you can collect the rainwater safely while keeping it free from mosquitos and use city water when your water reserves run out. In addition, rainwater is ideal for plants because it contains nitrate, an essential macronutrient that plants need. Have you ever noticed how green your plants get after the rain?
In closing, rainwater is the best source of water for plants. If you can only use it for your plants, do so. Unfourtanetly, in El Paso, we are not lucky enough to be able to use only rainwater for most garden setups. If you have a softener, try running a bypass for your plants. If you own a water softener, you can bypass your water softener to give regular tap water to your plants.