A weak colony does not recover on its own; it cannot use the forage, cannot defend itself and is open to disease. Strengthening is the work of turning such a colony into a functioning unit.

The first question is: why is it weak? Strengthening carried out without finding the cause wastes resources.

Find the cause first

• A queen problem: No eggs, irregular brood, raised drone brood → the queen is old, poorly mated or absent
• Disease: Abnormal brood, smell, deformed wings → diagnosis is essential before strengthening
• Varroa: A high mite load melts the colony away; adding bees is a temporary fix
• Starvation: No stores → feeding may be enough
• Robbing or pest pressure: Check the entrance and the surroundings

Never add to a diseased colony. Giving healthy frames only spreads the disease.

Equalising with sealed brood

This is the commonest and most effective method. A frame of sealed brood close to emergence is taken from a strong colony and given to the weak one.

• Sealed brood is preferred; open brood needs nurse bees, which a weak colony cannot supply
• Check the frame so as not to move the queen by accident
• Shaking the bees off prevents fighting between colonies
• One frame at a time; a weak colony cannot warm more

The method also lowers swarming pressure in the strong colony — two benefits in one operation.

Uniting

If the colony is very weak, uniting is wiser than strengthening. A colony that goes into winter weak is usually lost.

The newspaper method is common: a sheet of newspaper with holes is placed between the two hives; as the bees chew through it the scents mix and fighting is reduced. Decide beforehand which queen will remain and remove the other.

Reducing the space

A weak colony cannot warm or defend a large space. Remove surplus boxes, reduce the space with a division board, narrow the entrance.

This is the cheapest form of strengthening, using no resources at all, and often the most effective.

Feeding

If there are no stores, feeding is essential. But remember that feeding alone does not strengthen a colony: syrup gives energy, not bees.

Pollen or a substitute supplies the protein needed for brood rearing. Where there is no forage and brood is wanted, this is worthwhile.

Requeening

If the queen is the cause of the weakness, every other intervention is temporary. A young, well-mated queen restores the colony within a few weeks.

Timing

Strengthening makes sense in spring and early summer, when a growing season lies ahead. Trying to strengthen a weak colony in autumn is usually a waste of resources — uniting is the better course.