Fall feeding of bees may be necessary for several reasons:
- The beekeeper harvested too much honey
- Weak nectar flows or bad weather prevented the bees from collecting enough stores
- A colony—such as a newly installed swarm—got a late start and didn’t have enough time to collect enough stores
- The beekeeper wants to treat for Nosema and needs syrup as a carrier for the antimicrobial product
If one or more of these conditions exist and you decide to feed syrup, you need to do it before the average daily temperature drops too low. Once the temperatures are too low, the bees are unable to dehydrate the syrup to a moisture level—about 17%—that is suitable for capping. Syrup or nectar that is uncapped may ferment in the cell, and fermented substances are not good for bees.
Also, syrup that remains in the feeder will eventually mold, and it will cause excessive moisture to accumulate inside the hive. Once bees stop taking the syrup in the fall, any remainder should be promptly removed.
While spring syrup is made in the ratio of one part sugar to one part water, fall syrup is made of 2 parts sugar to 1 part water (weight or volume, it doesn’t matter). In case you forget which is which, just remember that spring syrup resembles nectar, which is thin and lightly sweet. Fall syrup resembles honey, which is thick and very sweet.
In areas where there is little chance of a fall nectar flow, it is best to take off the honey supers and start feeding early. What little nectar the bees bring it will be mixed with the syrup they store, and all of it will help them get through the winter.
Considerations for fall feeding include the following:
- Entrances should be reduced to protect the colony from robbing bees and yellow jackets, especially during a nectar dearth.
- Feeding stimulants added to the mixture, such as essential oils or Honey-B-Healthy, help the bees find the syrup and cause them to store it more quickly. They also retard mold growth and provide nutrients to the bees.
- If you use Fumagilin-B for control of Nosema, mix it into the syrup following the manufacturer’s instructions so that it gets dispersed evenly throughout the feed.
- Never feed syrup in an open container because the bees will climb in and drown. Many types of feeders are available that will deliver the food yet keep the bees from harm.
 Fermented nectar and syrup are easy to detect: bubbles can be seen in the liquid and it has a distinctive “yeasty” odor. Eventually, a light-colored foam may ooze out of the cells. If the weather gets too cold before all the liquid is capped, beekeepers sometimes shake the frames to dislodge the liquid before it has a chance to ferment.