What’s In a Nuc?

21 May

Every beekeeper should maintain a few nucleus colonies (“nucs” for short) in the bee yard at all times. I tend to keep anywhere from five to twenty nucs in my bee yard and I find them enormously useful. A lot of beekeepers recognize the benefits of having nucs, but are not clear about what a nuc is or how to make and maintain one. In this post, I’ll try to clarify what a nuc is. In a later post, I’ll write about what to do with a nuc.

Don’t Get Hung Up on the Common Definition

I attended a presentation about nucs at a local beekeeper association meeting a few years back. The presenter and the audience struggled mightily to clearly define what a nuc is. In particular, many in the audience struggled to see the difference between a nuc and a full size colony. The presenter proffered the common definition of a nuc as a “mini colony containing all the components of a complete hive” – a queen, brood, honey, pollen. I’ve heard nucs described as “little colonies with a motors on them” – suggesting that keeping a colony of bees in a small space requires intensive management to keep them from running out of room and swarming. Some of the presentation audience asked the obvious question: why bother keeping a “mini hive” when I can keep a full size colony instead — and get most or all of the same benefits?

At the time of the presentation, I was not keeping nucs and I almost gave up on ever keeping them because managing a “mini colony” would be as much trouble as managing a full sized one and I would rather have a big colony than a small one. Besides, I’m a hobbyist with no time for intensive management of a “motorized” colony of bees.
Fortunately, curiosity won out and I started experimenting with nucs. I quickly realized that the common definition completely misses the point of a nuc. Once I understood what a nuc REALLY is, I determined to keep a few at all times. In fact, at some times of the year nearly half the colonies in my bee yard are nucs. Yes. They are that useful.

Are Nucs “Mini Colonies”?

What is it about a nuc that is “mini”? I think it is fair to say that most beekeepers would point to a typical five frame “nuc box” to suggest that a nuc is a colony of bees kept in small boxes with room for a small number of frames. That makes a lot of sense because most of the benefits we hope to gain from keeping nucs don’t require the bees to have lots of space; lots of beekeepers get their start or replace dead colonies by buying a five-frame nuc. But, as we’ll see shortly, there are some problems with identifying a nuc by the size of the equipment it is housed in.

Another way to understand nucs as “mini colonies” is to think of them as having a small population of bees compared to a full size colony. This makes a lot of sense too, because keeping a lot of bees in a small space will lead to problems, including swarming. On the other hand, having a small colony in a big space will lead to robbing and loads of hive beetles. A colony populous enough to occupy a big space isn’t mini, right? All this leaves open the question what is the difference between a nuc and another colony that is not a nuc but has a small population (because of a hard winter and slow spring buildup, for example). There are problems with understanding a nuc as having fewer bees, but it at least explains why a nuc might be kept in small equipment – smaller colonies generally do better in smaller spaces. If I buy a five-frame nuc, bring it home, and immediately put it in two ten-frame boxes, is the nuc suddenly not a nuc any more?

Let’s compare some colonies from my bee yard to show why identifying nucs as mini colonies is problematic. Keep in mind that each colony we look at has a healthy population of bees that comfortably fills the available space.

My standard full size colony configuration is two deep 10-frame Langstroth hive bodies for the brood chamber, like the hive in fig. 1, which has three medium-depth honey supers added because it is honey-making season. This pretty obviously is not a nuc. It is a full-sized honey-producing bee hive.

Now compare fig. 1 with fig. 2. Fig. 2 shows what are pretty obviously nucs. They are housed in five frame deep boxes. These are the easy examples. Fig. 1 obviously is not a nuc, and fig. 2 obviously is. The next two photographs illustrate where the definition of a nuc as a “mini colony” gets murky.

The nuc in fig. 3 has 15 frames in it, which is fewer than the 20 frames in the standard full size colony’s brood chamber. It is starting to look less like a “mini colony” and more like a big colony. How many five-frame boxes can I stack up before the colony transforms from a nuc to a full size colony? If I add one more box to the nuc in fig. 3, it will have 20 frames – the same as the brood chamber in fig 1. Would adding a box transform this colony from a nuc into a full hive? Under the “mini hive” definition, it might – especially when the population expands to fill the space.

I could stack up five-frame boxes until the colony in fig. 3 is as big as the one in fig. 1, but five-frame boxes are not very good for keeping a huge colony in because the stack would get too tall to safely manage.

The hive in fig. 4 looks like the one in fig. 1, but without the honey supers. It is the standard hive configuration – two deep boxes containing a total of 20 frames. The only difference between this hive and adding a box to the hive in fig. 3 is width and height – the number of frames would be the same – each colony would have 20 frames.

The confusion deepens for beekeepers using 8-frame equipment instead of 10-frame equipment. My standard colony configuration is two deeps with a total of 20 frames. If I used the same standard two-box brood chamber with eight-frame boxes, I’d have only 16 frames – just one frame more than my three-box nuc in fig. 3. Is the hive housed in two eight-frame boxes a nuc? Or a standard colony?

In the easy cases, you can tell just by looking whether something is a full-size colony or a nuc. But what about the colony in fig. 4? It doesn’t look at all like a nuc. It is not in mini-sized boxes and it does not have a mini-sized population. Therefore, it does not fit the definition of a nuc as a “mini colony containing all the components of a complete hive” – it cannot be a nuc.

But it is a nuc, and I’ll explain why in the next section.

A Different View

I don’t think describing a nuc as a “mini colony” is very helpful for a lot of reasons. For one, nucs fluctuate in size, depending on the season and what they are being used for, and it is not easy to tell when a nuc crosses the line from “mini” to “big”. Every year, some of my nucs get tall – I’ve stacked as many as five boxes to make a nuc that has 25 frames in it. Why is that tall stack of boxes called a nuc, and not a full size colony?

More importantly, the “mini colony” definition describes a physical characteristic of some nucs but completely ignores the fundamental character of a nuc. In other words, the traditional definition suggests what a nuc might look like, but does not describe what a nuc is.

I didn’t understand why it is worth keeping nucs until I realized what they really are. A nuc is a colony of bees that is managed for use in a supporting role. I have two kinds of colonies in my bee yard. The first type is the nuc. The second type is the production colony. A production colony is a colony of bees managed with the intention of producing honey, pollen, or another hive product for human use. Note that these definitions are functional. They define colonies by what the the beekeeper uses them for, rather than by what they look like.

When we understand that nucs play a supporting role in the bee yard, we immediately can see why they are valuable. Our imaginations conjure up all sorts of ways that nucs could be used in our own operations, and we understand why nucs usually are small.
Now we can use the colony in fig. 4 to illustrate one way that the supporting role played by nucs can add management flexibility to your bee yard. At the beginning of the season, this was a production colony; I was managing it with the intention of taking a crop of honey from it. In the middle of the May showers, I realized that the colony had gone queenless for some reason. I suspected that, given what I saw in the colony and the persistent rain we were having, any attempt the colony had made to replace the queen had failed or would if there was a virgin queen trying to mate in a rain storm.
At this point I could have done one of two things. The first option was to keep managing the colony for production. The second option was to convert this production colony into a nuc by changing what it was being managed to do. In either case, I had to first verify the colony was otherwise sound (i.e., no major hive beetle or wax moth infestation or other signs of health problems).

If I chose the first option, I could combine a five-frame nuc into the production colony, thereby replacing the queen, restoring the brood nest, and boosting adult population all in one step. A neat trick not possible to perform without a nuc handy.

If I chose the second option, I could break up the colony and used it to boost the remaining production colonies. I could even have used it to build up other nucs to prepare them to divide into mating nucs for queen rearing later in the season.


I hope that defining a nuc as a colony of bees that plays a supporting role in the bee yard helps us to realize why nucs are such a big deal. If you’ve had bees longer than a few months, you know that we beekeepers have to pay attention and be flexible in our management practices. Maintaining a few nucs is one way to build multiple options to fix the mistakes we inevitably will make.

And what might we use a colony for, other than to produce honey and pollen? Stay tuned to find out!


(fig. 1) standard hive configuration

(fig. 1) standard hive configuration

nucs in five-frame boxes

(fig. 2) nucs in five-frame boxes











(fig 3) stacked nuc

(fig 3) stacked nuc


(fig. 4) what is this?

(fig. 4) standard configuration














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