pH balance in water important for healthy plants

By Bev Johnson | The Daily Journal

Published Saturday, March 15, 2008

As gardeners, we worry about the pH of our soil. We never think about the pH of our water. We think of rainwater as "pure" water, naturally neutral. Not so. Carbon dioxide in the atmosphere lowers the pH of rainwater to about 5.6, nearly as acid as vinegar. So what about city water? If you get your water from a city system, it will be alkaline. It has to be or it would eat up the older, lead water pipes that deliver water to many of our houses.

To find out what the pH of your city water is, call your local water department. In St. Paul, water is 8.2.

To make it fit for watering houseplants, St. Paul gardeners need to add 1 teaspoons of vinegar to 5 gallons of water to bring the pH to 5.6.

Take a look at your houseplants. We used to think it was the chlorine in city water that gave our plants brown leaf tips and prevented them from doing well. Maybe not.

Well water might not be all that great either. It can have significant amounts of calcium and magnesium in it. This will take even more vinegar to lower the pH.

One way to know if you have these salts in your water is to look at your flower pots. Do they have white crud around the top of the pot? You won't see that sort of stuff in your flower garden.

So what do you do? There is a pH monitor called Sunleaves that hydroponic growers use. It costs about $10. It changes color to tell you how acid or alkaline your water is.

An easy way to lower the pH of your water is to use vinegar. It's cheap, safe and easy to get. If you have trouble growing house plants, maybe all you need is a pH meter and jug of vinegar. House plants are a must in most homes. Not only are they decorative, they also clean up the air in our closed up, winter homes.

Call your water department, get a jug of vinegar and in a few months, you may need a machete to get to your bedroom.

Bev Johnson is a master gardener for West Otter Tail County.