Making up a nucleus: what goes in, and how many bees

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The two jobs a nuc does

A nucleus colony, a nuc, is five or six brood frames with a good population of adult bees, brood in all stages on at least three of those frames, stores of nectar and pollen, and a laying queen. 1 That is how the National Bee Unit describes the thing you would buy. It is a fair target for one you make yourself.

The first job is being the far end of a split. Leave the queen where she is in a colony that is working up to a swarm, and the cells, brood and bees you take off her need a box to live in.

The second job is insurance, and it is the one most hobby beekeepers actually want. A spare colony replaces a winter loss without you buying bees in. Wally Shaw notes that raising one yourself means waiting about four weeks, which is why so many people buy instead. 2

What goes in, and in what order

Have the nuc box open on the ground before you take the first frame out of the parent hive. Every minute a brood frame spends in the air is a minute the brood is cooling.

• A frame of stores against one wall. The outer combs of a nuc are allowed to be food only, so honey with a bit of pollen in it does the job. 1
• The brood frames into the middle, the same way round as they came out. Eggs and young larvae in the centre, sealed brood either side.
• More bees, shaken in off two or three further frames of open brood. People skip this step. It is the one that matters most.
• A second frame of stores, or a dummy board, against the far wall. Nothing empty for them to heat.

Use drawn comb rather than foundation if you have it. Check the frames fit your own hive before you go anywhere. Dark black combs are not worth putting in a new colony.

How many frames, and how many bees

The frame count is the easy half. This is the National Bee Unit’s standard for a good nucleus. 3

• At least three frames carrying brood, with brood in all stages.
• Four frames or more fully covered in bees.
• The equivalent of at least one full comb of honey and half a frame of pollen.
• Combs preferably less than one season old.

The purchase and sale guideline adds figures of its own. On the brood it wants a continuous pattern, at least 30% of the total comb area sealed, and no more than 15% drone brood. On food it asks for more than the list above. A six frame nucleus wants two to three combs of honey and a whole frame of pollen. 1

Shaw puts the floor lower. Three frames of brood and two of food, left to make their own queen, is his example of a safe minimum, and he says a more generous split is better. There is no fixed recipe. 2 Frames are easy to count and bees are easy to fool yourself about, so count the bees.

Flying bees go home

Here is the thing that catches everybody out once. Make a nuc up and stand it three metres away in the same apiary. By the evening every bee old enough to fly is back in the parent hive with the old queen. What you have left is whatever was too young to leave. 2

So take more bees than looks right, and take them off frames of open brood, because that is where the young ones are. Enough has to be left to cover the brood. Once the brood is kept warm, emerging bees make the numbers up quickly.

Shaw’s answer is to block the nuc entrance while he fills it, then move the box to a mating apiary at least two to three miles away. There is one exception and it matters. A nuc taken from a colony that is already set up to swarm has to stay put long enough for the fliers to go home. Move it straight away and the swarming urge goes with it.

A split board is the other way round it. The nuc sits on top of its parent colony with an entrance of its own. The fliers go back down to the queen below. 5 Whatever sits on top of a split board loses its fliers that way. So it needs enough bees to cover the brood, enough stores because it will not be foraging much, and a small entrance against robbing. 4

A mated queen, or a queen cell

Three ways to do it.

• A mated laying queen. The quick answer and the safe one, and what a bought nuc comes with.
• Sealed queen cells. Cheaper, and what you have anyway when the nuc is the far end of a split. A cell is sealed on day 8 and she emerges on day 16. 5
• Eggs and young larvae, and let them raise their own.

How many cells to leave is genuinely contested. The National Bee Unit’s swarm control sheet leaves one cell and no more. You keep a cell that is still open with a healthy larva showing in it, and take the rest down. 6

Shaw does the opposite in a nuc. He gives each one at least two cells and preferably more, still on the comb they were built on, with no picking and choosing, taken about day 9. He says plainly that this is not what the beekeeping books say. 2

There is no reconciling the two. The National Bee Unit applies its single cell rule to emergency cells in a queenless parent colony. Those are the same sort of cell Shaw is describing. Shaw calls choosing one cell for a nuc a thing to avoid, because the beekeeper is only guessing at what is inside it. Both are current advice and they do not agree.

Feeding it

Feed a nuc unless there is a proper flow on. A small colony has a small foraging force, and a wet fortnight in May will empty it. Feeding is also what gets any foundation in the box drawn out.

Thin syrup is the feed for this job, 1 kg of white granulated sugar in 1,260 ml of warm water. A frame feeder is the one the National Bee Unit picks out for nucleus colonies. It replaces a deep frame and sits right against the brood nest, so the bees can reach it in cool weather. 7 Making the syrup up has the quantities, and the feeders page has the rest.

Feed in the evening and keep the entrance small. Strong colonies rob weak ones, and there is nothing weaker in your apiary than a three frame nuc with syrup in it.

Keeping it warm enough

Bees heat the brood, not the box, but a small cluster starts at a disadvantage. It has more surface for its volume than a big one, so it loses more heat and burns more stores per bee doing it. 8

That is the whole argument for a nuc box. It is small on purpose. Do not undo that: dummy board against the last frame, no gap under the crown board, and a roof that sits down properly.

Open a young nuc less often than you would a full hive. Every inspection lets the heat out of a box with very little to spare.

When it goes up into a full box

Not on a date. A bought nuc is the one clear case. The National Bee Unit says to move it into a full sized hive after a day or two in its new spot, because it needs the room to expand, and it warns that correx boxes are only for the short term. 1 They are built for the journey.

A nuc raising its own queen is the other case. Leave it alone while she is out mating, and check at four to five weeks that she is laying. 2 Move it up once every frame is drawn and laid up and there are bees on the box walls.

Shallow nuc boxes are worth knowing about here. A nuc can start in a shallow box and have a deep box added later. It works just as well and only takes a bit longer to build up.

Taking one through the winter

An insurance nuc is only insurance if it is alive in March. That call gets made in August, not in November.

The National Bee Unit’s rule of thumb is a minimum of five standard brood frames covered in bees going into winter. Anything smaller should be combined with another colony, as long as both are free of disease. Below 9,000 bees, which is about three full British Standard frames of bees, the chances are poor. 8

So either build the nuc up into a full box and feed it like every other colony, or unite it into one. Uniting is not a failure. It is the same insurance, banked. Either way it gets treated for varroa with the rest of the apiary, at the smaller dose a small colony needs. Putting the treatment on has the figures, and autumn feeding has the weights.