Sunday, March 19, 2017

OVER WINTERING NUCS by beekeeper Fred

This article is the first of four to be written by ECWBA members that attended the Marathon County Beekeeper's seminar on March 18th.

The presenter on this topic, Adrian Quiney, has about an 80% success rate in overwintering nucs in the Hudson, Wisconsin area ( about 20 miles east of Minneapolis/St. Paul area).  He also has hives in 3 apairies so he wasn’t a novice promoting radical untested ideas.  His aim for overwintering nucs was to break his dependence on purchasing package bees every spring.  Hudson has a slightly colder winter climate than ours. 

His first comment was that you need a good varroa mite control strategy prior to attempting to overwinter nucs.  It can be chemical based, bee species based or brood break based. That said here is his process for overwintering nucs.

He constructs his own 5 frame nucs from ¾” wood, but most suppliers also sell a 5 frame nuc.  A 4 frame nuc may work but all of his experience is based on 5 frame nucs.  A 5 frame nucs is essentially a 8 or 10 frame deep simply cut down (narrowed) to hold 5 frames.  Each of the overwintering nucs is composed of two 5 frame deeps stacked one upon the other.  The bottom box has no holes.  The upper box has ¾ to 1 inch hole.  This is for ventilation or a winter exit in case the lower entrance is blocked by snow.  The bottom board and entrance reducers are essentially a cut down versions of standard size equipment.  Don’t be afraid to make your own equipment.  The presenter was by self-admission only a beginning wood worker.  Corner joints don’t need to be quality dovetail joints, but can be simple rabbit joints or no joints at all.  Some of his nucs were made of scrap lumber. 
On the top he places some sort of thin plastic sheet.  Almost any type will do;  an old feed bag, plexiglass, etc.  The main purpose of this sheet is to prevent the bees from eating into the next layer.  That next layer is 2 inch thick foam insulation cut to size to act as a cover.  In the summer a rock or brick is used to hold everything in place.
For nucs he plans to overwinter he starts the process in early June.  First he picks a full size and full strength hive (2 deeps) he wants to propagate.  This hive is already a winter survivor.  (Yes, he is sacrificing getting honey from that hive this year in return for more hives next year.)   A full strength hive is used since it is better able to raise quality emergency queens.  So he has 16 to 20 frames of bees and honey available for dispersal amongst 4 to 5 nucs.  Next he locates and removes the queen.  She can be used in a nuc or elsewhere.  Next he goes through the 2 deep full size hives and puts in notches in area of the brood nest that have 1 day old larvae. (See the article by Grandpa Jack about notching frames to promote queen cells)  This full strength hive that is now queenless sets to raising emergency queens.  An alternate would be to insert purchased queens if you have some special genetics you are trying to get into your operation.

The early June start is chosen based on 2 factors.  The bees need enough time to raise the new queen and brood.  Starting later than early June does not allow enough time for build up before fall.  You also want to minimize the number of varroa brood cycles the nuc goes through prior to the fall bee brood raising break.  Less varroa equals better survival.  Also the act of starting the queeless nucs provides a built in bee brood break in early June that also sets the varroa back.  Personally, I would probably give the donor hive a oxalic acid vapor treatment just prior to splitting it.
Seven days after doing the notching you inspect for queen cells.  The queen cells should be capped at this point.  Hopefully, there are many cells on a number of different frames.  He limits the number of queen cells per frame to 2. He removes any more than two. (If you are carefull somethings you can raise a queen from removed cells).  This minimizes virgin queen fighting.
Now he distributes the 16/20 frames among the nucs.  1 frame with at least 2 queen cells, 1 frame with capped brood, 1 frame honey,  1  frame with foundation.  Try to distribute any remiaing bees to balance out the nuc bee strength. So you end up with 4 to 5 nucs.

Then he leaves the nucs alone for 3 weeks.  At that time inspect for a laying queen. Expect a 20-30% failure rate.  If there is not a laying queen you need to either add a queen or re-combine the queenless nuc with a queenright hive.  This prevents the queenless nuc from getting laying workers. 

At this 3 week point he also adds the second brood chamber box with 5 frames to the nucs.
In mid August he weighs the nucs.  He feeds those that don’t weigh 50 pounds gross weight (hive, bees and honey).  He carries his bathroom scale out to the apiary for the weighing.  His data showed the hive weight declined 12 to 35 pounds over the winter. 
For winter he lines up the nucs next to each other so they are sharing a wall and thus minimize heat loss.  All entrances face south.  He is not too worried about drifting because the bees won’t be out foraging do to the lower temperatures.  He partially closes the upper vent hole.  Essentially he cuts a cork in half and stuffed it in the vent hole for the winter.  He then puts a plywood cover over the top.  This cover has a 3 inch lip to overlap the exposed 2 inch thick foam insulation outer cover.  The plywood prevents mice from chewing on the foam. Some plastic sheeting can be added to prevent water damage to the plywood cover. 

He showed data over about 10 years with a 80% winter survival rate. 

You can see of Adrian's work on Youtube.  Follow this link and click on Videos.

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