Beekeeping is uniquely challenging profession; one that seems to only grow in difficulty as agriculture and land use continues to change to serve a growing human population. The introduction of Tracheal mites, Nosema, and the notorious Varroa mite (+ viruses) have only amplified the struggle. One of the earliest records of storing colonies indoors is a letter from a beekeeper describing annual winter losses of 30% of his colonies. In a question to Dr. Doolittle, the beekeeper asked for advice to prevent such high losses in the harsh winters in Iowa (Doolittle 1902). The advice given was that insulation of the hives using chaff or placing the colonies in a cellar to protect them from the wind and cold might help reduce losses. Early adoption of sophisticated hive protection was pioneered by Canadian beekeepers to protect colonies from the harsh winter weather. A publication in 1926 titled “Wintering Bees in Canada” described how to prepare colonies for wintering outdoors and indoors. An excellent review of early indoor wintering is provided by McCutcheon (1984). Some of the wisdom from these older publications are still relevant today. While the motivations, timing and scale of indoor storage are different in the US, there is a lot to be gained from the great research and experience of Canadians in this practice.
Northern beekeepers and those drawn to the potential for large honey crops in northern territories have been especially tuned to the need to protect bees from the elements and prepare colonies for winter. In 1926 (Gooderham) wrote that successful wintering in harsh climates required three considerations:
1. Strong colony with young bees 2. Good weight 3. Protection from cold and foul weather
It is the protection from weather that motivated beekeepers in Canada and the northern US to purse the practice of wintering bees indoors. These conditions are still relevant today, along with an additional requirement for successful wintering.
The wintering of colonies in 2019 have a fourth requirement: 1. Strong colonies with young bees 2. Good weight 3. Protection from cold and foul weather 4. Low Varroa mite population (in September)
The addition of the fourth factor is an essential and complicated factor to wintering success. The Varroa factor impacts the other three requirements and the impacts can be imparted on the colony long before winter preparation occurs. The first requirement from 1926 now needs to be adjusted to state 1.) Strong colony with healthy young bees. The health of those strong young winter bees is determined in August and September and is highly negatively correlated with Varroa populations. It is possible to have strong colonies with low Varroa levels in November and have heavy winter losses if Varroa are allowed to feed on and spread viruses during the production of winter bees in August and September, even if the colonies were properly treated for mites in late September or October.
Number 3 on the list above is likely not a major motivating factor for US beekeepers. US beekeepers have had the option to successfully protect bees from the cold winter climates by moving their bees to California (or other southern states) before severe winter weather affects the bees. However, this management style has its own set of consequences – continued brood production, high colony densities, increased feed and labor costs, disease transmission, etc. An increasing number of beekeepers have turned to indoor wintering as a means to avoid the negative consequences of winter holding yards.
It is important to consider the purpose and/or motivation for the use of indoor storage as part of the overall management strategy of each unique operation. The following statements might have made for a good title for this publication and reflect underlying principles for the recommendations found herein. These sayings have become something of a mantra from beekeepers with experience in managing indoor storage.
“You get out what you put in” “Garbage in, garbage out” “Storages are not hospitals”
Indoor storage is not a cure-all and they are not suitable for all operations. All the work and preparation in the month leading up to the storage period are critical.
This document is intended to be a starting block to be built up and create a central repository of knowledge on the practice of indoor honey bee storage and the management surrounding storing bees in buildings. The following sections are the initial collection of invited contributions from individuals with experience from different aspects related to indoor storage.
We expect to learn more and openly invite additional collaborators to add to this work.
Following this introduction is - The “Ins” and “Outs." A section intended to cover the preparation of colonies before they go into storage and some precautions and advise for treatment of colonies when they get out of storage. This is mainly composed of advice gathered from commercial operations who have been storing bees indoors.
There are always many questions about building requirements for cooling, ventilation, etc. I invited Anthony Molitor from Industrial Ventilation, Inc to produce a section coving these common questions regarding building requirements. He has worked closely with commercial beekeepers and helped design and build successful indoor wintering buildings.
A common concern when presenting research or discussing the practice of indoor wintering is that it is done on such a large scale that smaller commercial beekeepers, sideliners and hobbyists think it doesn’t apply to them or the option is out of their reach. Chelsea Cook & Kimberly Drennan were invited to submit a writeup on their ongoing project utilizing smaller modular storage options that might become a more applicable solution for smaller operations or fit unique management styles.
There are constant questions and concerns about the economics of many aspect of commercial beekeeping; it was timely that DeGrandi-Hoffman and colleagues recently published a paper on economic aspects of commercial beekeeping practices which included a comparison of indoor vs outdoor winter storage. She was willing to produce a popularized version of that work based on the peer reviewed publication. Figures 1 & 2 should be carefully studied and considered in the context of each individual operation. Even if the exact numbers and annual management cycle from this study do not align with your operation the implications within figures 1& 2 have the potential to make an impact in the efficiency of any operation.