Spring Cleaning- The history of spring-cleaning of the house goes back to when a family, and often much of their smaller livestock, spent the winter confined to the "house". Several months of moisture condensation on the roof and walls combined with the accumulation of debris where pests could reside with impunity, lead to the need to remove potential harbors of infection. We need to consider the equivalent spring-cleaning for the hive where our bees have spent the winter confined with moisture on the walls and roof and the accumulation of debris but we need to think beyond this simple cleaning to a deeper sterilization.
Spring-cleaning for the bees is often considered simply scraping out the bottom board debris and opening up the front entrance to allow more air circulation but please consider an additional layer of cleaning. Each comb cell has the uses of storage and nursery. Years of use can foster a buildup of disease material on and within the cell walls. Statistics have shown that bees raised on old comb tend to have higher disease rates than those raised on fresh comb, presumed to be due to the buildup of disease material.
Molds and fungus can grow in the storage cells on the contents during winter when moisture condenses on the fringe of the cluster. Bee's wax in the honeycomb is porous and has little nooks and crannies where small particles can remain behind after being used as a storage cell. Thus bacteria, spores, and other infectious material can be left there even after the bees have "scrubbed" the walls.
The cells have a build-up of cocoons as each larva goes through it's cycle of 21 days, so, conservatively, each cell in the core of the cluster can have 12 cocoon layers after a single season. Each cycle includes the larval wastes excreted at the base of the cell with any remaining food before the larva spins its cocoon. Thus, the cell is slowly filling with debris that will feed any number of pests and harbor the buildup of infectious cultures. , The cell is "painted" with propolis before the cell is used again to seal this debris away from the next larva but the effectiveness of this sealing has highly variable effectiveness.
Our bees then benefit from the periodic removal of this harbor of disease material. This requires the replacement of old combs and the insertion of new. There are a number of strategies for this replacement.
Beekeepers with single or a few hives may want to replace two of the ten frames each year. This yields a five-year replacement cycle. Picking the two frames in the worst condition, or the oldest date marked on the top bar, and moving them to the outside positions early in spring during the first open-hive cleaning is one process. You can even do this in the fall in preparation for the spring to avoid additional work during the busy season. As the season advances and a nectar flow begins, these two frames can be removed for meltdown while two new replacement frames of foundation are inserted into the center of the box.
Beekeepers with more hives can replace whole boxes of frames by using brood boxes of foundation during the nectar flow and then remove the box of old frames the following spring after the bees have vacated them for the upper boxes. These "foundation" frames can also be extracted and put on the hives for next years early spring expansion rather than wait for good comb drawing conditions.
It is time to make your plans. How are you going to handle spring-cleaning for your bees? Keep them healthy and they will have an easier time fighting off other attacks.