Opening the Sides of the Broodnest - OSB

What you will need:

One to two boxes of new undrawn frames.


No queen excluder
No feeding
Frames are all the same size
Start at least a couple of weeks before you usual swarm season
Do every 2 weeks until into the main flow


A method for new beekeepers who don't have any spare empty comb coming into spring. To get at least a full deep box of comb built before swarm season, to help reduce swarming and to get a honey crop.


1. Develop wax makers well before swarm season.

2. Maintain wax making throughout swarm season and well into the main flow.

"Opening the Sides of the Broodnest" - Steps:

1. A few weeks before swarm season, move each outermost frame from a brood box up into the middle of a new (undrawn) box, placed directly above the Broodnest.

2. Insert a new frame (with a "hole") on each outside edge of the Broodnest in the brood box. (So that a Brood frame is only on one side of each new frame.)

3. Check them in 2 weeks and repeat the steps if comb in the new frames in the brood box have been mostly drawn, but now alternate the drawn frames that are moved up, with the undrawn frames.

4. Check again in 2 weeks. The new box should now be mostly drawn. Repeat the steps again with another new box on top.


  • You can start doing this as soon as Drones are starting to be raised and the weather forecast for the next week is warm.
  • For the bees to move into a box, I have found it best to have at least 3 drawn combs together, in the middle of the new box. When there is less than 3 frames in a box, they usually get emptied out. So if you have a spare drawn comb, the more the better.
  • This is for deep frames. If you use mediums the times will be more like 1 week.
  • Best to use all the same size frames.
  • As a guide, I would start Opening the Sides of the Broodnest around half way through the period between Cherry blossoms and Apple blossoms. The period between these blossoms for me is quite long, around 2.5 months. If it is around 1 month for you then you initially may need to use drawn comb instead of a partial frame of foundation. See Note 2 below.

More details:

"Opening the Sides of the Broodnest" is all about triggering wax production before swarm season and then maintaining wax production into the main flow. So the bees build more comb for raising brood and storing nectar and also use up incoming nectar to max the wax.

This method is for beekeepers who do not have enough drawn comb.

The new frames to trigger wax making should have no more than half a sheet of foundation. Cut vertically and placed centrally, it works well. There must be a HOLE close to the broodnest. The hole beside the broodnest is what triggers comb building, (the need to fill the hole).

The "Sides" of the Broodnest/Cluster are opened up, rather than inserting frames into the middle of Broodnest. This is important, so that the bees are not forced to heat a larger volume than what they are used to. It also doesn't split the Broodnest which could cause issues if very cold weather sets in. Inserting frames into the Broodnest can set back brood rearing and also cause issues such as chilled brood if cold weather sets in, especially earlier in the season.

Bees will often build mostly drone comb before swarm season if the frame is completely foundationless.

The hive should have a few frames with some capped honey, at least on the top corners. I prefer not to feed, but if they haven't got enough stores you may need to, as they will use up all their stores trying to fill the hole(s) with comb. Make sure you leave them some stores close to the broodnest in case bad weather sets in.

Once wax making has started, the bees will drawn out foundation.

Only the first couple of frames beside brood need to have a "hole" to trigger wax making.

As a guide, I would start Opening the Sides of the Broodnest around half way through the period between Cherry blossoms and Apple blossoms. The period between these blossoms for me is quite long, around 2.5 months. If it is around 1 month for you then you initially may need to use drawn comb. So when daily maximum temperatures start getting over 15°C /59°F, go into the hive and move the two outside frames up into a new box and place them together in the center (try to make sure there are no eggs in these frames.) Then find the outside edge of the brood nest. Insert a new frame on each side the outer edge of the brood nest.

The temperature is a guide to when you can go into the hive. It's when the bees are able to forage every day and fruit trees are flowering. But it's also the stage that the hive is at that is just as important. With a 10 frame deep box, I'm looking for at least 5-6 frames of brood and at least 3 frames with a decent amount of capped honey. If they don't have a good amount of stores, you are just going to stress them and if bad weather sets in, even cause starvation because they will use up the honey making wax. If they don't have that you should wait. Also, the hive should look full, with bees covering all frames. Look at the weather forecast for the next week. A few days of good weather will enable them to forage and get more stores in, whilst the wax makers get busy.

With different overwintering configurations you have different conditions to look for. In general I would say 2/3 brood, 1/3 honey.

5 frame Nuc - 3 frames with brood, 2 with honey
8 frame (double) Nuc - 5 frames with brood, 3 with honey
10 frame deep - 6 frames with brood, 3-4 with honey
Double deep - several frames with brood, 4 or more with honey

I believe this could be applied in many environments, that have winter temperatures below 13°C/55°F (this or below bees will cluster.)

If you only see 2-3 queen cells, DO NOT WORRY. This means they are superseding. As with Checkerboarding, the Broodnest can fill 3 brood boxes. The queen may be running out of stored sperm and needs to be replaced.

I only need to do this 2 or 3 times in swarm season. From then on just work in the supers.

Note 2:
After a number of discussions with people who have tried Opening the Sides of the Broodnest, it looks like a modification needs to be made if there is a fast and heavy flow in your area when Spring starts. Seems to be in places that have snow, and the transition between Winter and Spring is quite quick. I too would be reluctant to add partial frames while there is still snow around.

Apparently there is just too much nectar coming in and the wax makers either don't start or can't make enough empty comb to keep up in these areas.

Beekeekers in this situation are using empty DRAWN comb to Open the Sides of the Broodnest until this initial flow is over. This enables the Broodnest to be able to expand out sideways, without getting backfilled.

After this initial period has passed, then frames of Partial/Half sheet foundation can be used as per the method.


So let's look at an example using the following notation:

N = A new undrawn empty frame with no more than 1/2 a sheet of foundation.
D = A drawn comb with some honey, nectar or pollen.
B = A frame with SOME brood on it.

I have made the frames that I expect the bees to draw out in Bold.

Example of 2 Deep boxes. New frames have half a sheet of wax foundation.

(Bees emptied out the 2 drawn frames moved up to the top box previously):


(Expecting the bees to work on at least 4 new frames):


(Brood on bottom of frames in the top box, bees expanded in top more than expected):


What I do:

  • Pull out 2 new frames from the new box before opening the hive.
  • I typically only work in the top brood box.
  • Take out the outermost frame from the brood box and put it straight in the new box
  • Then slide the next frame out to the outer edge of the box.
  • You now have a gap between frames, blow some smoke in there.
  • Look for capped brood. If none, slide the next frame over and again look for capped brood.
  • Once you see brood, take out the previous frame before that and look for eggs or open brood.
  • You now know where the edge of the Broodnest is and you've only pulled out 1 or 2 frames to look at.
  • That is the only brood frame(s) that I look at. No need to look for queen cells, because if they are making wax and building comb they are unlikely to want to swarm.
  • Give them 2-4 new frames to work on. This helps to decrease the frequency that you need to go into the hive.

Main points:

  • Does not touch the broodnest, so it doesn't force bees to heat a larger volume than they are used to heating. Which can cause chilled brood.
  • Does not split the Broodnest, so if cold weather sets in there is no possibility of having the cluster split and emergency queen cells made by the queenless cluster.
  • The bees still have direct access to the frames that were beside the brood nest, but now they are above instead. Not a problem, when heat rises.
  • The bees can build the comb in their own time, but the empty space gives them an incentive to build comb.
  • Develops comb building before swarm season, which helps to reduce swarming. Due to extra comb for nectar storage and using up of nectar to make wax.
  • Enlarges the size of the brood nest when the bees would usually be reducing it by backfilling, because the queen lays in empty comb as it is being built.
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