Sprinkler Irrigation (Frost Protection)

There are numerous considerations for growers thinking of investing in an irrigation system.  One is successful frost protection in areas where freezing temperatures occur during bud, blossom and fruiting requiring the use of sprinkler irrigation to protect these plants’ parts from being injured or killed.  Aluminum tubing is an essential part of distributing water to the plant.  To be effective and efficient, the grower needs to check the aluminum tubing gaskets before laying out the tubing in the field.  If the gaskets have started to dry out or crack, they need to be replaced to ensure a good seal and prevent unwanted leakage causing pressure loss.  This is just one step to successful irrigation for frost protection.

Using sprinkler irrigation for frost protection is a common method, especially for high-value crops like fruit trees, berries, and vegetables. Here’s a breakdown of what to consider, along with other options, plus pros and cons.

️ Sprinkler Irrigation for Frost Protection: What to Consider

✅ Key Considerations:

1. Application Rate:
   Must apply enough water continuously to counteract evaporative cooling and keep the plant temperature above critical levels. Typical rates: 0.1–0.2 inches/hour.

2. Timing:
   Start sprinkling before temperatures drop below freezing (32°F / 0°C) and do not stop until ice melts off plants, or you risk more damage.

3. Water Supply:
   Requires a reliable, high-capacity water source, often 20–40 GPM per acre depending on system and crop.

4. System Type:

   • Overhead impact sprinklers are most common.

   • Solid-set systems or portable aluminum pipe systems are typically used.

   • Uniform distribution is crucial.

5. Wind Speed & Humidity:

   • Works best in low wind, high humidity conditions.

   • Less effective or even harmful in dry, windy conditions due to rapid evaporation and cooling.

6. Crop Sensitivity & Growth Stage:
   Know your crop’s critical damage temperatures, which vary by species and stage of development.

Other Frost Protection Methods

1. Wind Machines (Frost Fans)

• Function: Mix warmer air aloft with cold surface air.

• Best Use: On radiation frost nights with temperature inversion.

2. Heaters (Orchard Smudge Pots or Propane Heaters)

• Function: Add heat to the air.

• Expensive to operate and often used in combination with fans.

3. Row Covers / Blankets

• Function: Trap ground heat near the plant.

• Effective for low-growing crops and small operations.

4. Foggers / Humidifiers

• Reduce radiative heat loss, but less common and location-specific.

Pros & Cons of Sprinkler Frost Protection