Frost damage to the floral parts of grain heads (prior to, during and immediately after pollination) is surprisingly common in California, other mountain states, and many cereal-growing areas in the world. Development of early maturing varieties has intensified the problem in all areas, particularly where cereals are fall sown. Many seed and fruit crops also can be damaged by frost. Most plants are extremely sensitive to temperature in stages of rapid growth and reproduction. This is especially true of plant reproductive organs.