Colony Strengthening

Strengthening a colony is the work of turning a weak bee colony into a unit that can exploit the nectar flow and defend itself, by adding sealed brood, adding bees, reducing space, feeding, requeening or uniting. The first step is always to find the cause of the weakness; boosting a colony without knowing the cause wastes the strength of healthy colonies.

Why is a weak colony dangerous?

A weak colony does not easily recover on its own. Few bees can keep only a little brood warm; few foragers bring in little nectar. It cannot defend its entrance and is exposed to robber bees and hornets. Wax moth and small hive pests quickly take over the unoccupied combs. And when weak colonies are robbed, diseases and mites spread through the apiary with the robbing colonies.

Why is the colony weak? Find the cause first

Strengthening with sealed brood (equalising)

This is the most common and most effective method. A frame of sealed brood about to emerge is taken from a strong colony and given to the weak colony. Within a few days hundreds of young bees emerge from this frame and join the weak colony.

1. Choose the donor colony: A healthy, strong colony, preferably one that is under swarming pressure.
2. Choose the right frame: A brood frame that is mostly sealed, with cappings starting to open here and there.
3. Check for the queen: Make sure the queen is not on the frame.
4. Shake off the bees: Shake the bees on the frame back into the donor hive to reduce the risk of fighting.
5. Place it next to the brood nest: Put it right beside the weak colony's brood nest, where the bees can keep it warm.
6. One frame at a time: A weak colony cannot keep more warm; if necessary, a second frame is given a week later.

Sealed brood is preferred to open brood: open larvae need plenty of nurse bees, and a weak colony cannot carry that load. This method also reduces the strong colony's swarming pressure, so one operation brings two benefits.

Adding bees and swapping hive positions

• Shaking in young bees: Young nurse bees can be shaken from the brood frames of a strong colony into a weak one. Young bees tend to stay in the new hive; to reduce fighting, a little smoke or a spray of thin syrup to mask colony odour can be used.
• Swapping hive positions: During a nectar flow, the positions of a strong and a weak hive are swapped in the daytime. The strong hive's foragers return to the old site, i.e. to the weak hive. This should only be done if both colonies are healthy and forage is plentiful; during a dearth it can cause fighting.

Reducing space: the cheapest way to strengthen

A weak colony cannot keep a large space warm or defend it. Remove surplus boxes, use a dummy board to confine the colony to the number of frames the bees cover, and reduce the entrance. When the hive volume matches the number of bees, the brood stays warm, stores are defended and the risk of wax moth and robbing falls.

This method costs no resources and is often the most effective. Transferring very small colonies into a nucleus hive serves the same purpose.

Feeding: it provides energy, not bees

In a colony without stores, feeding is essential. But remember that syrup alone does not make a colony grow: syrup provides energy, while the protein needed for brood rearing comes from pollen.

• Thin syrup (about 1 part sugar to 1 part water) stimulates brood rearing in mild weather.
• Pollen or a pollen substitute makes sense when you want brood reared while there is no pollen in nature.
• Feed a weak colony inside the hive and in the evening; syrup spilled outside starts robbing.

Requeening

If the queen is the cause of the weakness, all other interventions are temporary. A young, well-mated queen will bring the colony round within a few weeks in the right season.

• The old or failing queen is found and removed; the colony is left queenless for a few hours to a day.
• The new mated queen is introduced in an introduction cage with a candy plug; the hive is not opened for about a week.
• In a colony with laying workers, a queen is usually not accepted; it is more realistic to unite these colonies with a sound colony or to shake their bees out within the apiary so they disperse.

Uniting: one strong colony from two weak ones

If the colony is very weak or the season is too late, uniting is wiser than strengthening. A colony that enters winter weak is often lost; a united colony survives the winter, and the numbers can be regained by splitting in spring.

1. Decide which queen will stay; remove the other.
2. Place a single sheet of newspaper on top of the strong colony's brood box and make a few small slits in it.
3. Place the weak colony, box and all, on top of the newspaper.
4. The bees chew through the newspaper in a day or two; during this time the scents mix and fighting is reduced.
5. A week later, rearrange the frames and remove any empty ones.

A diseased colony is never united. If one of the two colonies is queenless and has been queenless for a long time (i.e. has laying workers), uniting must be done with extra care.

The right time to strengthen

Strengthening makes most sense in spring and early summer, when the colony has the growing season ahead of it and every frame of brood given pays back many times over. Trying to strengthen a weak colony in autumn often weakens the strong colonies and wastes resources; uniting is the better choice at that time.

Common mistakes

• Boosting without finding the cause: If there is a queen or disease problem, the brood given is wasted.
• Giving open brood: The weak colony cannot nurse it, and the brood gets chilled.
• Giving too many frames at once: Brood that cannot be kept warm dies.
• Moving the queen by mistake: The strong colony is left queenless.
• Weakening the strong colony too much: Taking too many frames from the donor colony before the main flow means two medium colonies and a low honey yield.