The Preparation of Bees for Outdoor Wintering

by Everett Franklin Phillips; Geo. S. Demuth

For more northern localities more protection is needed. The amount indicated for Washington has been used with success in places as cold as northern Ohio and even in Canada, but in these places the insulation during the coldest seasons is usually augmented by heavy snows. These are not at hand every winter, or may be lacking during the coldest part of the winter, and it is, therefore, wise to provide more packing, especially on the sides and top. For a climate such as that of New York or Wisconsin, 8 inches of good packing on the sides and 1 foot on the top probably will be enough for good wintering every year. The amounts recommended for the different zones of the United States are given in Table I ([p. 15]).

A belief is current among many amateur beekeepers that good results may be obtained by using hives which have 2 inches of packing built in the sides and somewhat more on top. This amount is insufficient in winter in all parts of the country except the southern portions of the Gulf States. A common practice is to wrap some straw or corn fodder around the hives, but this may do more harm than good if the wind can blow directly through it. A covering of roofing paper with perhaps a little paper packing underneath is practically worthless in insulating value.

TYPES OF PACKING MATERIAL.

There is little difference in the insulating value of the various materials which may be obtained easily for the packing of hives in winter. Exaggerated claims have been made by some beekeepers for such materials as broken cork or certain commercial insulating materials, but it is safe to say that there is not 25 per cent difference between the poorest and the best of the available insulating materials, provided, of course, that obviously poor things such as corn fodder and straw be eliminated. Sawdust, fine planer shavings, forest leaves, chaff, broken cork, and such materials may be used, the choice depending chiefly on the availability of the materials. In general it may be stated that the smaller and the more numerous the dead air spaces confined in the packing, the greater will be its efficiency in insulation. If forest leaves are used they must be gathered the year before and stored, as the leaves fall some time after the bees should be packed. If sawdust is used it is best not to pack it down tight, but if forest leaves or planer shavings are employed it is essential that they be packed in closely and that the containers be completely filled. Broken cork, such as is used in the shipping of certain types of grapes, is good and has the advantage that it does not hold moisture as does sawdust. In all cases the packing should be placed in some sort of box which will be rain-proof and thus protect the insulation from rains and snow, for all insulating materials lose part of their efficiency when wet.

BOTTOM PACKING.

There has been considerable discussion among beekeepers as to the value of placing packing material below the bottom boards of the hives. This is usually provided by placing the hives on 2 by 4 inch supports or on racks of 4-inch material. Those who have opposed this have pointed out that "heat rises," overlooking the fact that while warm air attempts to rise, if this is impossible other avenues of escape of warm-air currents may be set up. Furthermore, and more important, they have overlooked the important fact that heat escapes from the hive not only by convection currents but by conduction and radiation as well. In an extensive series of experiments performed by the writers it was found that in hives packed at the top and sides most of the heat escapes through the bottom boards; in fact, this was so noticeable that the packing at the top and sides never served its full purpose so long as heat was escaping rapidly at the bottoms. It may be stated, therefore, that so long as the bottoms are unprotected there is little insulating value in materials piled on the top and sides beyond about 2 inches. This amount is insufficient for most parts of the United States, therefore bottom packing should be considered as absolutely essential wherever bees are packed.

To get the value of bottom packing it is absolutely essential that the entrance be reduced, but it need not be closed. In a long series of temperature readings on hives packed for several winters, the authors were able to keep a temperature of 50° F. on the bottom boards of packed hives directly behind the entrance openings. Those who have condemned bottom packing have labored under the mistaken notion that it is impossible to prevent currents of cold air through the entrance. This is entirely possible if the entrances are adequately reduced. The conclusion to be drawn from the experiments performed is that unless the bottoms of hives are well packed, the beekeeper ought not to imagine that he has packed his hives at all well.

Fig. 2.—The winter packing cases used in the Bureau of Entomology apiary: a, Detail of tunnel to hives. In the specifications given in this Bulletin ([p. 9]) provision is made for room for a third hive body to be added in the spring.