Guarding Outdoor Plants from Frosts and Freezes with the Help of Ice
Protecting Outdoor Crops from Frost Damage: The Sprinkler Irrigation Method
Outdoor crop growers often face the challenge of protecting their crops from frost and freeze damage. One effective method to combat this issue is the use of watering sprinklers, which spray water onto plants when temperatures approach freezing.
As the water freezes, it releases latent heat, helping to maintain the plant surface temperature near 0°C and preventing plant tissues from dropping to damaging lower temperatures. This process forms a thin layer of ice on the plants, acting as an insulator and preventing frost injury during sensitive periods.
Key Points
- Mechanism: The heat released during the freezing of water (latent heat of fusion) helps keep plant tissues from falling below freezing point, despite air temperatures being lower.
- Water application: Light and continuous irrigation via sprinklers is necessary to maintain a protective ice layer. Careful control is required to avoid excessive water usage and runoff.
- System design: Effective freeze protection requires analyzing the land's size, slope, water source pressure, and crop water needs to design an efficient sprinkler layout.
- Additional benefits: Besides frost protection, sprinkler irrigation can improve water efficiency, nutrient delivery (fertigation), and crop yield uniformity.
- Limitations: This method is mainly effective during radiation frosts when temperatures drop gradually at night, rather than during rapid freeze events or very low temperatures beyond the system’s capacity.
Cautions and Precautions
- It is advised for inexperienced growers to seek advice from experienced growers and/or Extension personnel before using this frost-protection system.
- The system should be turned off when temperatures rise to or above those that cause damage, even if the sun comes out and starts melting the ice.
- The weight of ice can cause branch breakage in crops with dense and tall canopies.
- If the sprinkler system is not designed properly, not enough ice will be produced, potentially causing damage to the plants.
- Ice accumulation on plants can be substantial and may require several days of continuous operation of the sprinklers.
- After melting, the high volumes of water can create a sanitary hazard if the containers sit in a flooded area.
- Under no circumstances will The Ohio State University, agency, officer, or employee be held liable to any party who may choose to rely on information contained within this fact sheet.
The Ohio State University assumes no liability for any errors or omissions in this fact sheet, and the views and opinions expressed do not necessarily reflect the position of The Ohio State University.
Start small by protecting a small crop, and expand the protected area gradually as comfort level increases. Remember, careful management ensures both effective protection and efficient water use.
- To protect crops from frost damage, 4-H gardeners can consider using the sprinkler irrigation method, as it effectively maintains plant surface temperature near freezing.
- In this method, by releasing latent heat during the freezing of water, the sprinklers create a protective ice layer on plants, preventing frost injury during sensitive periods.
- Gradual implementation of the sprinkler system is advisable, starting with a small crop and expanding the protected area as comfort and expertise increase.
- During the winter gardening season, this watering strategy not only guards against freezing temperatures but also improves water efficiency, nutrient delivery, and crop yield uniformity in the home-and-garden setting.
