Assess frost risk for your location and crop stage. Plan sowing dates to avoid flowering during frost windows.
Risk depends on: temperature, duration (hours below 0°C), crop stage, and topography. Frost hollows can be 2-5°C colder than surrounding areas.
Forecast -2°C, wheat at flowering.
Frost during flowering causes sterility. Above -2°C usually safe, -2 to -4°C moderate damage, below -4°C severe. Canola very sensitive — -2°C at flowering can cause 100% loss.
Southern Australia: August-October (spring frosts). Highest risk 2 hours before sunrise on still, clear nights. Low lying areas are 2-5°C colder.
Choose later flowering varieties. Avoid early sowing. Plant frost-tolerant crops in hollows. Wind machines. Sprinkler irrigation before frost. Leave stubble.
Very sensitive: Canola, chickpeas, lentils. Sensitive: Wheat, barley, oats at flowering. Most sensitive stage is flowering (10-20% loss per degree below 0°C).