How to Grow Shrubs with Hard Water

While soft water can be used outdoors for washing a car, it is harmful to many plants, trees and shrubs.

"Hard" water contains magnesium and calcium. As the minerals in hard water can place a coating on household items -- such as dishes or shower stalls -- most homeowners typically dislike it. Many homes have a water softening system that replaces the hard water minerals with other minerals, including sodium. While the softened water is more beneficial for use in appliances, it can be harmful to both plants and people. When watering outside plants -- such as shrubs -- the use of hard water is recommended, as well.

Instructions

1. Collect rainwater in barrels or tubs for use on outdoor shrubs. Special kits can be purchased to attach to downspouts, siphoning rain water to the desired holder, rather than allowing it to enter storm sewers. Rain water is devoid of harmful chemicals -- such as chlorine -- commonly found in tap water; further, it does not contain the sodium contained in softened water. A hose can be attached directly to a rain barrel for watering shrubs; or, use a watering can to dip the rain water out of the storage tank.

2. Hire a plumber to install a water softener bypass valve on your home's water softening system. This allows water to be diverted through the plumbing lines without being chemically altered. A lever can be turned, shutting off the softener; a hose can then be attached to the outside faucet, and hard water can be applied to the shrubs. The diverter can then be turned off before soft water is needed outside -- for washing the car, for example.

3. Leave outside water lines tapped into the hard water line before it enters the softener to provide a watering source for outside shrubs. Hook the hose up to the faucet and water plants as needed.

Tips & Warnings

• Rainwater chemistry varies per area; while considered naturally "soft," it can contain trace elements of minerals found in hard water.

• Water that is "softened" is not recommended for use on lawns, gardens or house plants; the sodium content can damage the plants.

• Avoid hard water that comes from alkaline or chalky areas; the minerals it contains can be harmful to plants.

• Do not use hard water on plants that are susceptible to damage from contact with lime.

References

• Texas A&M University: Hard Water - To Soften or Not To Soften
• Drought Smart Plants: Water Capture - Rainwater
• Plumbing Concepts: Water Treatment FAQ

Resources

• DuPage Water Conditioning: FAQ
• Water Filter Guru: Water Softener Bypass Valve
• Plant Propagation Misting System: Salt Injury To Ornamental Shrubs And Groundcovers