Even with a quality greenhouse cover, extreme cold nights can still pose a risk to sensitive plants. Using a frost cover for plants inside the greenhouse adds an extra layer of insulation during freezing conditions. Frost covers work by trapping heat close to the plant surface, reducing exposure to cold air. When paired with a durable winter greenhouse plastic, this combination creates a layered defense against frost damage. Many growers rely on this approach to protect seedlings, vegetables, and ornamentals during unexpected temperature drops.