How to use a slatted rack
The slatted rack is my all-time favorite piece of bee furniture, and I wouldn’t try to keep bees in a Langstroth-style hive without one. I insert one whenever I build a new hive and leave it there year-round. If you’re not familiar with them, a slatted rack (sometimes called a brood rack) fits just beneath the lowest hive body and above the Varroa screen or bottom board. It has the same outside dimensions as the brood box and is about 2 inches deep.
Slatted racks provide dead air space below the brood chamber. This layer of air helps to keep the bees cooler in summer and warmer in winter. In the summer when populations are high, bees congregate in this area which reduces congestion in the hive, spreads out the heat load, and facilitates ventilation by fanning. This increase of space and lessening of heat seems to decrease swarming as well. In the winter, when the entrances are reduced, the air space within the slatted rack acts as an insulating layer between the brood chamber and the cold area below the hive. It also removes the brood nest further from the drafty entrance.
Because a slatted rack moves the bottom of the brood chamber further from the entrance, the queen tends to lay eggs all the way to the bottom of the frames, thus extending the brood pattern.
Here are some caveats about using slatted racks:
- If you use a screened bottom board, the slats need to run from front to back— the same direction as the frames. The idea here is that the mites will fall between the slats and then through the screen. If you have the type of rack that runs crosswise, fewer mites are going to fall through so your Varroa screen will be less effective. Similarly, the number of slats should match the number of frames. If you use only nine brood frames in a ten-frame box, your slatted rack should have nine slats. Some manufacturers have designed racks that can be modified for this configuration. There are also slatted racks made specifically for 8-frame equipment.
- At one end of the slats (running perpendicular to them) is a flat board about four inches wide. This goes at the front of the hive and is said to reduce air turbulence at the entrance.
- But the most important thing to remember about slatted racks is this: they have two sides, a deep side and a shallow side. The shallow side goes up. Repeat. The shallow side goes up. If you put it in upside down, the bees will draw comb into the empty space. The next time you try to reverse brood boxes, you’ll first have to cut away the comb and brood hanging off the bottom. You can’t even set the box down without doing serious damage. This is not fun, especially when the box weighs 90 pounds and the temperature is 90 degrees. (Hmm . . . Do you hear experience speaking here?)
However, once you get your slatted racks successfully installed, you’ll be a convert. Whatever the reason, hives with racks seem to do better than hives without.