Using Hot Water for Greenhouse Irrigation: Risks and Solutions

Warm Water Yes, Hot Water No—Protect Your Plants

While irrigation components (PVC, polyethylene) can handle household hot water temperatures, your plants cannot. Hot water shocks roots and foliage, causing damage or death.

Safe Approach

• Use a thermostatic mixing valve (like those in showers) to blend hot and cold water to a safe 70–85°F range.
• Install the mixer at the irrigation supply point before the zone valves.
• Monitor soil temperature to ensure it stays within optimal range for your crops (lilies, carnations).

This setup gives you the soil-warming benefit without the risk of thermal injury.