Tag Archives: grafting

Spot the queen part 2

If you managed to spot the queen in the image a fortnight ago you did better than I did … although she was clipped and marked, there was no sign of her in the bees clustered around the hive entrance. Furthermore, once they’d returned to the colony she was clearly absent (an oxymoron surely?) at the next inspection – no eggs, several well developed queen cells and the usually placid bees were rather intemperate. Perhaps she was lost in the grass, got injured or was otherwise incapacitated during swarming? Perhaps she did return and was then done away with? A pity, as they were good stock, and had already produced three full supers this season. However, I’d also grafted from this colony – see below.

Here’s another picture of a queen that’s a bit clearer … but wasn’t when inspecting the colony.

I performed a colony split using a Snelgrove board. The colony was clearly thinking about swarming, with a couple of 1-2 day old unsealed queen cells present during the inspection. I knocked these back and introduced a frame of eggs from better stock. On checking the nominally queenless half on the seventh day they behaved as though they were queenright (no new QC’s on the frame of eggs provided or elsewhere, calmer than expected etc.). I must have missed a sealed cell (presumably a tiny one) when splitting the colony the week before. After a bit of searching – it was a crowded box – I found a small knot of bees harrying a tiny queen, by far the smallest I’ve seen this year and not really any bigger than a worker. I separated the majority of the workers and managed to take a couple of photos.

The abdomen is not well shown in the picture but extends to just past the protruding antenna of the worker behind her. Overall she was narrower and only fractionally longer than the workers in the same colony. When surrounded by a golf ball-sized clump of workers she was effectively invisible.

Midget Majesty

Midget Majesty

The picture above was taken near the end of May, shortly before I removed the first batch of cells from a cell raising colony set up with a Cloake board. These queen cells were from grafts raised from the colony that subsequently swarmed from the bee shed. The cells went into 3+ frame poly nucs arranged in a circle split, the queens emerged during glorious weather in the second week of June, matured for a few days and – just about the time they would be expected to mate – got trapped in the colonies by ten days of very poor weather.

And they're off

And they’re off …

However, over the last few days the weather has picked up, I’ve seen queens leaving on orientation or mating flights and the workers have started piling in pollen. All of these are good signs and suggest that at least some of the queens are already mated and laying … we’ll see at the next inspection.

First grafts of the year

The weather continues to be unseasonably cool, with this week being pretty typical of what we’ve recently been experiencing.

More of the same

More of the same

Nevertheless, I’m assuming it will pick up when we get to June so have finally started queen rearing. In previous years I’ve had mated queens in the first week of May, so we’re nearly a month late. I set up a strong colony (with poor temper – these are destined for requeening as a priority) as a queenright cell raiser using the Ben Harden system, grafted on Saturday and checked them 24 hours later.

Mixed success

Mixed success …

Seven or eight of the 10 grafts appear to have taken, with a 3-4mm collar of fresh wax around the lip of the plastic cell cup. In the image above the two covered with bees and #4 and #6 have this collar. If you look inside the cell you can see a larva floating in a bed of Royal Jelly. In contrast, #3 and #5 have only a very short wax collar and the cells are empty – for whatever reason these larvae have been rejected. I’m a little concerned that #4 and #6 aren’t getting a lot of attention from bees … time will tell if these have worked.

These cells should be capped on Thursday. Until then, despite the remaining OSR in the surrounding fields, I’ll feed the colony with thin syrup. As I write this it’s raining again …

Here we go again ...

Here we go again …

Queen rearing and the June gap


Here we go again

The oil seed reap (OSR) and hawthorn have finished here and there’s very little forage available for colonies. To make matters worse the weather has been changeable, restricting the time available for colonies to forage. Small colonies, such as casts that have been attracted to bait hives, have lacked sufficient numbers of foragers to store any nectar and have needed feeding. Small, weak, nucleus colonies have starved unless supplemented with syrup. In contrast, large swarms have fared much better – it’s almost as if there’s some sort of size threshold below which the colony isn’t able to cope with adverse conditions.

This poor weather has caused significant problems for queen rearing.

  1. Virgin queens are taking ages to get mated, far longer than happens in settled weather. Many of the days have had warm, clear mornings, but with thunderclouds building up around lunchtime leading to a deluge in the afternoon – the peak time for queen mating. Many mating hives have gone queenless over the last fortnight.
  2. Without a significant flow, getting cells started – at least in the queenright queen rearing system I use (the Ben Harden method) – means the colony must be fed syrup for the few days between adding the grafted larvae to the cell raising colony and the 9th day (after egg laying) when the cells are sealed.

There’s not much that can be done about improving the chances of getting queens mated, other than ensuring a supply of freshly emerged virgin queens ready to take advantage of any suitable breaks in the weather. After more than three weeks in a 2-3 frame nucleus I’m usually pessimistic about the chances of getting the queen successfully mated.

In contrast, with relatively little effort you can feed syrup to the cell raising colony, thereby ensuring the larvae are given the best chance of success. If the cell raising colony has supers on I temporarily remove them to another hive to prevent the bees simply storing syrup in with nectar.

Queenright queen rearing colony

Remove the supers …

In practice the easiest way to achieve this is to set up the queenright cell raiser the day before grafting (as described in detail previously) with a clearer board on top of the upper brood box, beneath the supers. When you come to add the grafted larvae, first remove the supers which are now cleared of bees and put them aside, gently slide the cell bar frame between the frame of unsealed larvae and pollen, add 150-200ml or 1:1 w/v (thin) syrup to either a fat dummy feeder or frame feeder in the upper brood box, then put the crownboard and roof back. Add the removed supers to other strong colonies in the apiary.

3 day old QCs ...

3 day old QCs …

Unless the weather dramatically improves I then check the colony daily, adding a further 150-200ml of thin syrup to the feeder. This just takes a few minutes and results in minimum disruption … a quick waft of smoke at the entrance, the same amount through a slight gap beneath the raised corner of the crownboard and then gently remove the crownboard. The day after grafting I check the larvae to see how many have been accepted. There’s no need to check the cells on the next 3 days (despite the picture shown here), simply add a bit more syrup to the feeder. On the fifth day after grafting the cells should be sealed and there is no longer any need to continue feeding. In addition to preventing tainting the honey supers with syrup, removing the supers also concentrates bees into the brood boxes.

Ben Harden queen rearing – cell raising

[See previous posts on introduction, setup and grafting for queenright queen rearing]

With any queen rearing it is critical to be aware of the timetable. Eggs are laid, hatch on day three, grafted on day 4, queen cells are sealed on day 9 and the virgin queens emerge on day 16. There’s not much variation around these timings; if you graft a larva that is too old it will still be sealed into the cell on day 9 (after the egg was laid), but will have had less opportunity to feed well and so may generate a sub-standard (‘scrub’) queen. If you thought the larva was 18-24 hours old, but it was actually 48-60 hours old, it will emerge up to a day and a half before you expect it to.

Oops … too late

Oops … too late

This is “not a good thing” as the newly emerged virgin will run amok through the colony destroying all the other queen cells which will then be partly or completely torn down. Alternatively, if all of the larvae are a little older than you thought they’ll all emerge and have a melee in the upper brood box of your colony setup for Ben Harden queen rearing. If you’re really unlucky an undersized virgin will squeeze through the queen excluder and slaughter your mated, laying, queen in the bottom box. All of this can be avoided by understanding the timing of events involved in queen development and keeping good records.

Queen rearing diary

Tom’s Tables …

BIBBA provide a copy of Tom Robinson’s table, essentially a queen rearing diary in Excel format. It’s designed for using Jenter or Cupkit systems, rather than grafting, but the underlying development timetable – the dates when the cells are sealed and when the queen emerges – are of course identical. I’ve modified a copy to suit my own queen rearing programme, using grafting and mini-nucs. By simply entering the grafting date, the remainder of the timetable is automagically completed, so there should be no reason to miss one of the critical dates. In the same way that good records are required to select stock to graft from, you should keep a record of both the queen rearing activity and the performance of the resulting queens.

Getting the timing right

How can you avoid early-emerging queens? Pretty easily in practice, as long as you do the following:

  1. Graft young larvae only – following the guidance in the earlier post on grafting.
  2. Check the larvae within 24 hours to ensure they have been accepted.
  3. Check on the day the cells should be sealed.
  4. Check them finally 24-48 hours before expected emergence. By this time the sealed cell may show signs of being crowned – a sort of thin darkened ring around the tip of the cell which is a good indication that emergence is going to happen shortly.
  5. Cage the cells in a hair roller to trap any virgin queens that emerge earlier than expected (you can do this anytime after they’re sealed).
  6. Use the cells before the queen emerges.
  7. Keep good records and remember that queen development is unaffected by the vagaries of the weather or your social diary … graft young larvae and use the resulting queen cells 10 days later.

Looking after grafted larvae



With a little practice a success rate of at least 80% should be achievable when grafting. As described previously, you can easy tell whether the grafting has worked by examining the cell cups about 24 hours later. You’re looking for a 3-4mm relatively smooth, slightly curved wax rim added to the cell. It’s very thin and fragile at this stage. Accepted grafts will also be covered with workers building the cells and feeding the larvae – you may not be able to see the spigot or cell cup at all. Gently move these bees aside if necessary (don’t shake or brush them off) with your finger. It’s actually possible to determine whether the larvae are accepted as little as a couple of hours after grafting but I usually prefer not to disturb the colony again (and often graft late afternoon, so it’s usually getting too late in the day).

Ben Harden cell raiser

Ben Harden cell raiser …

Assuming the cell raising colony is wells stocked with bees I rearrange the boxes at this first inspection so that the Ben Harden brood box is on the top of the stack. The main reason to do this is to save your back. Only do it if there are ample bees in the colony; you do not want the cells to get chilled by placing them over a couple of near-empty supers. In a strong colony, I’ve had three or four supers separating the queenright bottom brood box and the cell raising brood box. In the picture (right) the hive nearest the camera is a Ben Harden cell raising colony. There are three near-full supers between the lower and upper (BH setup) brood box. In addition, since the OSR is nearly over and the stores are capped, I’ve moved one full super  over a clearer board above the upper brood box, emptying it ready for extraction.

Fat dummy with integral feeder

Fat dummy …

The next few days are critical. The larvae need to be well fed and the cells need to be drawn out fully. If there’s no flow the cells may be ignored. To prevent this feed a small amount of thin syrup (1:1 w/v) in a frame feeder in the upper box. This is where a fat dummy with an integrated feeder is useful. Arrange this so that the feeder is next to one of the two pollen frames and add about 100-150ml of syrup daily until the cells are sealed. You barely need to disturb the colony to do this … a waft of smoke, lift or slide aside the crown board, add the syrup and close up again. There’s no need to check the cells, the frame of unsealed brood or the bottom box (we’ll come back to these two shortly).

If there is a good flow it is not necessary to feed the colony. Since this is essentially a standard production colony (with an additional upper brood box) the bees should continue to store nectar in the supers.

Are they sealed?

Brace comb and sealed cells

Brace comb and sealed cells

Five days after grafting the cells should be sealed or about to be sealed. The cells will by now be reasonably well sculpted, with a characteristic pitted appearance. The exception is the cell tip which will be pale smooth wax. When checking the cells don’t shake or jolt the cell bar frame and don’t keep the cells out of the colony longer than necessary. Once sealed the colony no longer needs feeding. In a good flow the bees are likely to build brace comb in spaces on the cell bar frame and to fill this with nectar.

Colony inspections

Ben Harden rogue queen cells

Knock ’em off …

Queens emerge on day 16 (counting from the day the eggs were laid), about twelve days after grafting. This is sufficient time for the colony to swarm, so you must continue with your standard weekly inspections. Simply lift off the upper brood box, gently put it down on an adjacent hive roof, or the upturned roof of the queen rearing colony. Remove the supers if present. Remove the queen excluder, check the bottom box for queen cells in the normal way, then reassemble. Do not forget to put the queen excluder back (or the newly sealed cells will all be torn down). You must also check the frame of unsealed brood in the upper box as they may be making queen cells on it. If so knock them all off. You only need to do this once as there should be no young larvae left once your grafted larvae are in sealed cells.

v1 … too narrow, too shallow

Two frame nuc box

If there are queen cells in the bottom box (but they haven’t swarmed) I make up a small nuc with the queen, a small amount of brood and a frame of stores in a two frame nucleus box. I then knock all of the queen cells back. If they generate more they’ll be well behind your own grafted larvae. That being the case, use one of the sealed grafted cells to requeen the colony. If the bottom box swarm it’s not a major problem as long as there are enough bees left to keep the grafted cells warm and well fed. If you want to use other swarm control measures remember that the cell raiser has done its job now … you can remove the sealed cells and place them in a suitable incubator until you use them for requeening (just before or after emergence).

Caging the cells


Nicot Cupkit

The advantage of the Nicot Cupkit system is that push-fit “hair roller” cages are available to protect the cells and to prevent an early emerging queen from destroying the rest of your hard work. These can be added soon after the cell is sealed, but I usually leave them a few extra days during which time the workers provide all the care the cells need. During this period they will usually sculpt the cell extensively. The only problem is if they build lots of brace comb between cells before you get a chance to fit the cage. If they do, a little gentle surgery with a sharp knife should be sufficient to trim them down to fit into the cage. Don’t force things. You don’t want to squeeze or crush the developing queen. 

Using the cells

You should use the cells about 10 days after grafting, which gives you sufficient leeway should a queen emerge a little early. They can be added to mini-nucs, 2-5 frame nuc colonies or full colonies … all of which will be covered in the future.

YBKA Spring Conference

York College

York College

I’m delighted to be talking  – twice (!) – at the Yorkshire Beekeepers Association Spring Conference in York on Saturday. With Stephen Martin (bee recognition and the Asian hornet), Jay Evans (beenomics – is that a real word?), Ben Jones (nutrition) and Liz Collison (neonicotinoids) also on the programme it promises to be an enjoyable day.

Update – it was a very enjoyable meeting and I’d like to thank the YBKA, Roger Chappel and Michael Badger for their excellent hospitality. My talk on queenright queen rearing using the Ben Harden system was well attended and generated some interesting questions. Abelo had a small trade stand selling all sorts of ‘essentials’ including some competitively priced radial extractors.


‘Grafting’ is the transfer of selected larvae from a donor colony into artificial cups from which new queens will be raised. It is probably the aspect of queen rearing that beginners find most daunting in prospect – perhaps not surprisingly as it involves manually moving a less-than day-old larvae (about the size of a comma in 12 pt. Times New Roman font) to a new location. However, it’s a lot easier to do than to describe, is easy to practice and you can tell if you’ve been successful within 24 hours.

In my opinion the preparation and maintenance of the cell raising colony and the use of mini mating nucs both require more skill than actually grafting the larvae for queen rearing.

Things that are needed for successful grafting

  • a source of suitable larvae
  • good lighting and good eyesight (help is available with both)
  • a grafting tool of some sort
  • a cell bar frame with cell cups to transfer larvae into
  • a warm, damp cloth and somewhere to sit

Source of suitable larvae

There are essentially two criteria that are important here – the age and the genetic quality of the selected larvae. The first of these is straightforward – you need to use larvae that are as young as possible, perhaps 12-18 hours after hatching from the egg. How do you determine the age of the larva? The easiest way is to choose the smallest larvae possible from a frame containing brood in all stages. Because the queen generally lays in rings you’ll usually find the smallest larvae right next to the oldest eggs on the frame. Fresh eggs stand up from the bottom of the cell, older eggs lie horizontally. Look around the cells containing the horizontal eggs. Suitable larvae are the same size as an egg, or perhaps even fractionally smaller. These larvae are so small they haven’t yet adopted the fully curved ‘c’ shape.

Keep good records

Keep good records

One of the reasons to rear your own queens is to have bees with the characteristics you want. This is the genetic quality of the starting material. This means you need to keep records of the behaviour of your colonies, scoring them for desirable or undesirable traits. This can get very complicated, but doesn’t need to be. In addition to general aspects of colony health (chalkbrood, viral diseases, Varroa levels) I keep records of temper, following and running on the frame as my primary interest is working with bees that are docile and easy to handle. Temper and running are scored on a simple 5 point scale and I use colonies with consistently the best scores for grafting. Following is scored as a simple yes/no … and any that score yes are re-queened.

Good lighting and good eyesight



Suitable larvae are small and you need to be able to see them clearly. You need both hands free, so do not rely on a magnifying glass. Buy a cheap set of strong reading glasses. Don’t be self-conscious about this … style doesn’t matter (anyway, you probably wouldn’t be a beekeeper if you worry too much about appearance) but strength does. Check the strength you need by looking for commas on a page in a standard paperback book, probably at a closer distance than you would read a book. I don’t need reading glasses for reading, but have +2.5 dioptre glasses for grafting.

Good lighting is critical. Don’t rely on the sun for this … you’ll inevitably be grafting on dull overcast days at some point. Get a battery powered LED head torch as used by campers. Ideally get one with at least 4 white LEDs and 2 red LEDs. The white ones are usually divided into two highly directional ones, and two providing general illumination. Use them all on together. You’ll need the red LEDs later …

Grafting tools

Use size 00 or 000

Use size 00 or 000

There are all sorts of tools available for grafting, ranging from the cheap and cheerful – and nearly ubiquitous – Chinese grafting tool to very expensive cranked, left or right hand-specific specialist items with exotic wood handles. Try a range of different types (at least the affordable ones) to see which you get on with best. However, I recommend you first try a 00 sable artists brush. Of all the grafting tools I’ve used, this is by far the easiest in my view. Protect the bristles using the sleeve stripped from a short piece of electric flex when it’s not in use.

Cell bar frame

Nicot Cupkit system

Nicot Cupkit system

You can make artificial wax cups from melted beeswax and a rounded dowel former. Far easier though are the plastic cups available from beekeeping suppliers like JzBz. Better still are those provided as part of the Nicot Cupkit system, consisting of a dark brown spigot, a cream coloured socket, translucent brown cups and a ‘hair roller’ cage. These are available separately from suppliers like ModernBeekeeping and are inexpensive.

The cell bar frame consists of a standard brood frame with one or two cross-bars to which the cups for grafting are attached. You need to be able to easily access the base of the cups. Therefore either hold the cross bar in place with a single gimp pin at either end (so it rotates), or make the cross bars slot in and out of the side bars.

For the Ben Harden queenright method of queen rearing I usually graft 10-20 larvae in rows of five or ten. Firstly this type of cell raiser isn’t as strong as the sort of three box queenless monstrosities some people use, secondly I can only conveniently get about a dozen or so queens mated at any one time.

Cell bar frame

Cell bar frame

Attach the spigot firmly to the cross-bar with gimp pins. Push-fit the socket onto the spigot and push the cell cup into the socket. If you have two cross-bars and intend to use the hair roller cages to protect the sealed cells make sure there is enough ‘headspace’ to fit them easily – remember the bars will be covered with bees when you do this. Probably the best way to achieve this is to have the cross-bars rotate along their axis.

Are you sitting comfortably … ?

Take a seat

Take a seat

The goal of grafting is to move good larvae from the cell in which the egg was laid into a new artificial cell, without damaging or chilling the larva. To do this you need to work quickly, carefully and efficiently. Find somewhere to sit near the donor hive that it is in light shade. Take a stool or folding chair to sit on and a piece of thin wood to lay in your lap on which the cell bar frame and the frame with larvae can be placed. Take off your veil. Make sure the things you need are close to hand – a hive tool or scalpel, your grafting tool of choice, glasses and head torch. Lay a damp cloth across the board to keep both the frame with larvae and the grafted larvae in a humid environment. I usually leave the cloth hanging over each end of the board, and fold these ends over to protect the frames.

Grafting in practice

Retrieve the acclimatised cell bar frame from the cell raising colony. Don’t bother putting anything in its place – you’ll be returning it within 30 minutes or so (but do close the hive up). Go through the donor hive until you find a frame with eggs and young larvae on it. I try and avoid shaking the frame hard, so give it a gentle shake to remove the flying bees, then brush off the adhering nurse bees (again, don’t push the frames together, but do close the colony). Take the frame to the location where you’re going to be grafting. Arrange your glasses and head torch, the wooden ‘table’, damp cloth and cell bar frame. Relax! Find a patch of suitable larvae …

  1. Arrange the frame with the top bar towards you – that way the cells also slope towards you making it easier to see into the base.
  2. Cut down the cells using a scalpel or your hive tool – the aim here should be to improve access to the larvae in the base of the cell. I usually simply lever apart a row of cells.
  3. Working calmly and efficiently pick individual larvae from the donor frame and transfer them to the cell bar frame.
  4. The precise way you manipulate the larva differs depending upon the particular type of grafting tool in use. If you’re using a paintbrush dampen and straighten the bristles (in your mouth), slide it underneath the larva, lift it out, lower it to the base of the new cell cup and release the larva by gently rotating the brush.
  5. When you’re not searching for suitable larvae from the donor frame keep it covered with the damp cloth. Likewise, keep the grafted larvae covered other than when you’re transferring them. This way you minimise the chance of them drying out.
  6. If you have trouble transferring a larva, if you end up rolling it around the cell cup, if it sticks to the side wall or if there’s any doubt at all about it then flick it away, lick the brush again and choose another.
80% take

80% take

It probably takes 30-45 seconds per larva when they’re easy to find. You can minimise this time by cutting down the wall of a row of cells and then working your way along the row, grafting each in turn. Don’t worry if it takes longer. The more practice you get the more efficient you will become at finding and transferring larvae. An acceptance rate of 80-90% should be expected with a little practice.

Gently return the cell bar frame with the grafted larvae to the cell raising colony. Use minimal smoke … you want the larvae to be accepted straight away and fed with copious amount of jelly. Remember that the cell cups containing the grafted larvae must be vertical.

Don’t forget to return the frame of unused larvae and eggs to the donor colony.

Did they work?

24 hours later

24 hours later

You can (and indeed should) check whether the grafted larvae have been accepted 24 hours after introducing them to the cell raising colony. Open the colony with the minimum use of smoke, gently raise the cell bar frame and look for a 3-4mm wax ‘collar’ around the edge of the plastic cell cup. If you look into the cell there will be a good bed of Royal Jelly with the larva floating on top. Grafts that have not been accepted might have a thin trace of wax around the cup edge, but nothing like 3-4mm.

If the overall acceptance level is low consider grafting again straight away. There is no need to reacclimatise the frame, simply pull out the cell cups and replace them with fresh ones. You even know which frames have day old larvae in them … they’re the ones which had horizontal eggs yesterday.

Ben Harden queen rearing – intro

Locally bred queen

Locally bred queen

The ‘Ben Harden’ method is an approach used to raise queen cells in a queenright colony. It offers a number of advantages that make it particularly suitable for relatively small-scale beekeepers, for beekeepers who want only a limited number of queens (10’s rather than 100’s, though the latter is possible if well organised) or for beekeepers who are taking their first steps in queen rearing. Consequently, it is also suitable for using within an association during queen rearing courses.

The advantages include:

  • it requires only a limited amount of additional equipment, including a spare brood box and two overwidth “fat dummies
  • it uses honey production colonies in a way that has little or no impact on foraging, and hence nectar collection
  • it uses a queenright colony which does not need to be “boiling with bees” and which is both easier and more pleasant to handle
  • it requires only limited manipulations of the colony

The general principles of this approach are straightforward and are reasonably well described by the late Dave Cushman modified from an article by Ben Harden in Bee Improvement (the BIBBA magazine). Further information is available in A simple method of raising queen cells written by Ben Harden (#59 in the Beekeeping in a Nutshell series available from Northern Bee Books).

This is the first in a short series of posts covering the basics of queen rearing using the Ben Harden queenright method. Each post covers one of the key stages in the method, which are:

  1. Preparation of the equipment and setup of the colony for queen rearing (part 2; Ben Harden queen rearing – setup)
  2. Grafting larvae (part 3; Grafting) and production of queen cells (part 4)
  3. Getting virgin queens mated (part 5)

It is possible to use this method to raise queens if you start with a single colony, using it as a source of larvae, the cell raising colony and the colony used to harvest nurse bees for populating the mini-nucs from which the virgin queens will be mated. This is not really recommended … at the very least you need a range of colonies to judge and choose the best as the donor for the larvae.

It is a also very good method to use in associations running queen rearing courses. Individuals taking part prepare a colony for cell raising, grafting is done communally using good stock and cells are distributed 24 hours after grafting.

Checking grafted larvae

Checking grafted larvae