Nucleus Colony Management

A nuc is a small hive with the same frame size as the main hive, usually holding 3–6 frames; the same word is also used for the small colony living in this box (nucleus colony, nucleus). It is the beekeeper's most flexible tool, used for many jobs such as queen mating, splitting, hiving swarms, keeping spare queens and selling colonies. Keeping a few nucs in the apiary stops the loss of a queen from becoming a crisis.

What is a nuc used for?

• Spare queen: A laying queen can be given at once to a colony that has become queenless or whose queen is failing. This is the most valuable use of a nuc.
• Queen mating: A ripe queen cell or a young queen is given to the nuc; the queen mates here and starts laying.
• Increasing colony numbers: New colonies are set up with frames taken from strong colonies.
• Swarm management: A captured swarm is temporarily put into a nuc; making a nuc from a colony inclined to swarm breaks the swarming impulse.
• Source of support: Young bees or sealed brood can be given from a nuc to a weak colony.
• Making up winter losses: Nucs set up in autumn and overwintered replace losses in spring.
• Buying and selling colonies: Between beekeepers, colonies are mostly sold as nucs.

How many frames should a nuc have?

Nucs usually have between 3 and 6 frames; the most common is the 5-frame nuc. A small nuc uses few bees but is fragile; a large nuc is more robust but ties up more bees and frames.

It is critical that the nuc has the same frame size as the main hive. Frames must be freely movable between nuc and hive, and when the nuc grows its frames must be transferable as they are into a full hive.

Features of a good nuc box

• A narrow, closable entrance: It must be possible to reduce it against robbing and close it completely for transport.
• Ventilation: A mesh ventilation opening in the lid or floor prevents the bees from suffocating during transport.
• Insulation: A small colony struggles to hold heat; a polystyrene or thick wooden body is an advantage.
• Room for a feeder: There should be space for a frame feeder or a top feeder.
• A sturdy lid and catch: In transport the lid must not slip and the frames must not rattle.
• Handholds: Side grips for easy carrying.

Wooden nucs last a long time and can be surface-disinfected with a flame. Polystyrene nucs are light and warm; however, they can suit wax moth and rodents, and cleaning them needs care. Cardboard nucs are only for transporting colonies.

How do you make a nuc? Step by step

1. Choose the frames: From a strong colony take one frame of sealed brood, one frame with eggs or open brood, and one frame of honey and pollen. Make sure the queen is not on these frames.
2. Add bees: The frames are moved together with the young bees on them. Because foragers will return to their old hive, shake in one or two more frames of bees.
3. Arrange: Put the brood frames in the middle and the honey-pollen frame at the side; fill the remaining space with drawn comb or foundation.
4. Solve the queen question: Give a ripe queen cell or a mated queen (introduced in a cage), or let the bees raise a queen from eggs. The last option is the slowest.
5. Prevent the loss of foragers: If possible, take the nuc a few kilometres away; if it is to stay in the same apiary, reduce its entrance and give extra bees.
6. Feed: If there is no nectar flow, give light syrup; during a dearth, feeding should be done in the evening.

What should you look for when buying a nuc?

• Frame size: is it the same as your own hives?
• Bees and brood: are most of the frames covered with bees, and is there brood of all ages?
• Queen: is there a laying queen, preferably of known age and marked?
• Health: are there sunken, perforated or discoloured cells in the brood, bees with deformed wings, or large numbers of mites?
• Comb: are the combs very old and dark? Fresh comb is preferred.

Nuc risks and care

Because it is small, a nuc carries far more risk than a full hive and needs more frequent checks:

• Robbing: The biggest threat to a nuc. The entrance is kept narrow and no spilt syrup is left.
• Heat balance: On cold nights a few bees cannot cover the brood; the brood gets chilled.
• Pests: Combs the bees cannot cover are an ideal environment for wax moth.
• Starvation: A small number of foragers use up the stores quickly.
• Varroa: Making a nuc can create a broodless period that gives an opportunity for mite control; but mite levels must also be monitored in the nuc.

Moving a nuc into a full hive

1. When almost all the frames in the nuc are covered with bees and the weather is warm, it is time to transfer.
2. Put the hive in the nuc's place; line the frames up in the middle of the hive in the same order.
3. Add drawn comb or foundation at the sides; limit the space with a dummy board according to the colony's strength.
4. If there is no flow, feed; the space is opened up gradually as the colony grows.

Overwintering nucs

A nuc can be overwintered; however, stores, insulation and moisture control are critical. A nuc set up in autumn must have a laying queen, enough young bees and enough honey and pollen stores for the winter before winter sets in. Nucs wintering side by side or in a divided hive benefit from each other's warmth; a nuc placed on top of a strong colony with a mesh divider board also benefits from the heat rising from below.

A nuc that survives the winter means a ready reserve in spring: a queen for a queenless colony, a boost for a weak colony or a new hive.