Rieselhilfen

Rieselhilfen are devices or materials used to prevent or mitigate frost damage to plants. The term, of German origin, literally translates to "frost aids" or "frost helpers." Their primary function is to protect sensitive vegetation from low temperatures that can cause cellular damage, leading to wilting, discoloration, or death.

Common forms of Rieselhilfen include the application of water. When water freezes, it releases latent heat. If a sufficient amount of water is continuously applied to plants during a frost event, the heat released by the freezing water can keep the plant tissue at or slightly above the freezing point, thus protecting it. This method is particularly effective for fruit crops, where the ice forms on the outside of the plant rather than within its cells. Specialized irrigation systems are often used for this purpose, delivering a fine mist of water that freezes into a protective ice coating.

Other forms of Rieselhilfen involve physical barriers. These can include horticultural fleece or covers placed over plants to trap heat from the soil and provide insulation. In some agricultural settings, even temporary structures or wind machines might be employed to mix warmer air from higher altitudes with the colder air near the ground, thereby raising the temperature around the plants. The effectiveness of any Rieselhilfe depends on factors such as the plant's hardiness, the severity and duration of the frost, and the specific method used.