Almond growers frequently ask how long almond flowers can be effectively cross pollinated after opening. AH almond varieties grown in California require cross pollination by honeybees to produce a crop. Since the important almond varieties usually start blooming during warm weather in February, the bloom period is often interrupted and prolonged by inclement weather. During these intervals pollinizing insects may not be active and any flowers that were open but not cross pollinated before the severe weather are lost unless they remain receptive until the weather is again favorable for insect activity. The cross pollination of flowers that open during periods of warm rains or strong winds may also be delayed.