When to put colonies in cold storage?

• We conducted a study with colonies that spent the summer in North Dakota. We put one set of colonies in cold storage in the second week of October. A second set of colonies were put into cold storage in the second week of November.
• We chose the October date based on when the maximum amount of sealed brood from the last brood cycle in the fall is in the colony.

Looking at the numbers

Bees were in North Dakota (ND) in September and were put in cold storage (CS) in either October or November

 In northern latitudes, the best time to put colonies in cold storage is mid-October

 

Colonies put into cold storage in October or November are similar in size in January. However, due to differences in age structure of the colony population, colonies put into cold storage in October are larger after almond bloom than those put in cold storage in November.

Shown below is a typical colony put into cold storage in October and evaluated in March. Both the brood and population levels are strong. 

Conclusions

• Cold storage recommendations are for colonies located in areas where brood rearing ends in the fall.
• Putting colonies in cold storage in October can produce colonies that are larger before and after almond bloom compared with those put in cold storage in November.
• The key to having large colonies before almond bloom is controlling Varroa in August, and managing colonies to maximize their size in the fall.
  • Combine colonies in the fall before putting them into cold storage