Winter Preparation for Vancouver Beekeepers

      It's September and time for Vancouver beekeepers to prepare for winter.  Actually winter preparation is an ongoing task (Beekeeping Calendar for B.C.).  The main reasons our bees die over the winter is starvation, colonies suffering from parasitic mite syndrome, too few bees to heat the cluster and moisture.  I complete my winter hive setup by the middle of October.  Much of what you do in preparation depends on your management style of beekeeping (virtually nothing for the extreme natural beekeeper to intense management for others).  This is a revised post from last year and are just a few suggestions based on my experience keeping bees in Vancouver.  Beekeeping is very location dependent so for those outside of Vancouver revise accordingly (Check out the Winter Management section of our library).
     Over the years my winter survival rate has improved (last few years near 100% on 30 hives).  Folks ask what is my secret and I tell them I never put to bed for winter a weak colony.  When I say above winter preparation is an ongoing task I mean addressing a weakness at it's infancy by treatment or requeening long before September.  Adding frames of bees to a weak colony now won't make it a strong colony just a more populated weak colony.  Some of the practices I use for winter preparation are 2x4 under rear of hive to allow drainage down the front and not on the cluster, R5 insulation under the outer cover to reduce condensation, candy board added at start of winter, insulate, tar paper and mite test board in place.  Once again this is location dependant and I'm sure others will find other practices that work well for them.  I completed a formic acid treatment in August and will possibly do another later in September (mite check).  I have screened (eighth inch) entrance reducers to allow for treatment during wasp predation season (unusual low yellowjacket population this year but fairly strong bald faced hornet presence - picking off bees at hive entrance).  We have the normal skunk scrapings at the hive entrances this year and a first for me, a pair of sparrows that spent most of the summer picking off bees at the hive entrances (feeding their young).  Pretty good honey production year despite the cold, wet spring and early summer. 

     To address the food issue you will need about 10 deep frames or 15 medium frames of honey (65 lbs or 30 kgs) for an average sized colony to survive the winter.  In our specific location (Strathcona) we still have a good availability of nectar and pollen with many different plant species still in flower in our 4 acre garden and the surrounding area.  Due to global warming plants in Vancouver can begin to flower 2-3 weeks earlier than in the past so our forage shortage begins in mid September (the Goldenrod and common Aster are in bloom now).  The problem occurs when the temperatures are still warm and dry enough from mid September through mid October for the colony to stay active.  An active colony without a natural food source may consume much of the winter food supply.  I'm fortunate this year to have a good supply of honey frames from my stronger hives that I can share with my weaker hives. If the food reserves are low it's a good time to feed 2 to 1 syrup.  You can feed during formic acid treatment by adding the feed either before or when you add the formic pads.  You cannot open the hive during the treatment period.  This article "Feeding Bees in Winter" describes the different methods of feeding at different temperatures.  The girls will take a 2 to 1 syrup down to about 12 celsius (53 fahrenheit) after which they find it too difficult to dehydrate for storage.  Some beekeepers will feed syrup baggies on top of the frames in colder temperatures on the theory that heat from the cluster warms the syrup.  I've not tried this.   An issue with syrup feeding this time of year is making sure most of the syrup the bees store gets capped.  The uncapped syrup will become a source of winter moisture and mold.    
     To address our main foraging shortage which occurs from mid September to mid October I have separated the root balls of common Asian Asters for planting and transplanted the invasive Canadian Goldenrod (Aster).  When mature the common Asian Aster becomes a 1.5 by 1.5 metre (4 by 4 foot) bush with hundreds of flowers and can bloom well into October.  We have a few hundred autumn flowering variety Asters in our 4 acre garden.  Other late bloomers in our garden are Japanese Anemone, Mint, Autumn Joy Sedum, Scarlet Runner Bean, Jersulam Artichoke, and the invasive Japanese Knotweed  (Nectar Plants of British Columbia).  A mixed diet is beneficial for the girls so some other late blooming plants are Caryopteris 'Dark Knight' (Blue Mist Spirea), Dahlia, Hardy Fushia, Seven Sons flower (Autumn Lilac), Impatiens omeianan, Camellia sinensis (Hardy tea bush) and Osmanthus fragrans (Fragrant Olive) (Nutritional Value of Bee Collected Pollens and Pollen Sources).  I will avoid the temptation to plant the invasive late blooming ivy and Himalayan Balsam. 

It's good at this point to make sure you have your emergency winter feeders ready if you plan to use them. A major cause of colony death is late winter starvation (February - April) which can be solved by the use of an emergency winter feeder like this one from Beverly Bees (Candy Board).  During a prolonged cold spell bees may be unable to access honey on the other side of the box. A candy board directly above can be a lifesaver.  

They're easy to build with 1x4's and quarter or half inch wire mesh and can be a colony lifesaver.  You can quickly check on the feeders through the late winter to gauge the status of the food supply (Feeding Bees in Winter).  
     In the Greater Vancouver area there are some differences in winter food requirements based on available foraging days and available forage. Because of the  effect of the North Shore Mountains precipitation varies from 150+ inches (380 centimeters) annually at the upper altitudes of the mountains to 30 inches (75 centimeters) along the U.S. border.  This effect reduces precipitation and increases hours of sunlight as you move southward.  It can be sunny in the south and cloudy and rainy by the mountains.  An obvious benefit to late and early season foraging.  This is particularly beneficial in March and April when we have a lot of flowering plants available but marginal foraging weather.  The graph below divides Greater Vancouver into 9 zones with 9 being the upper altitudes of the North Shore Mountains and 1 being the southern region along the U.S. border (Greater Vancouver Precipitation).  As the crow flies this is a distance of less than 30 kilometers or 20 miles.

Though active at lower temperatures I have found high population foraging in our apiary at 12 degrees celsius (53 fahrenheit) in March (Willow trees, Forsythia, Flowering Cherry).

This means more flyable, foraging weather the further south you live and the more active the colony with the additional needed sunshine warming the hive and bees.  The activity of the bees is directly linked to the number of hours of sunlight on the hives.  For optimum colony health maximize the sun exposure on your hives (South to southeast exposure with minimal shade).  We moved our apiary because it was surrounded by fast growing Black Locust, Willow and Cottonwood trees (Great pollen and nectar sources).  Other than occasional bearding the hives didn't seem adversely affected by the extreme heat this summer (2021 - 40 celsius/ 100 fahrenheit).  * Update: Unfortunately we had 3 times the normal rainfall this September followed by temperatures 3-4 degrees cooler than normal in October decreasing the available foraging time.  Feeding may be essential for most.  Check your winter food supply.      
      Also effecting food availability and feeding in preparation for winter is whether you are in a rural agricultural or urban setting. The rural, agricultural areas in Surrey, Delta and the Fraser Valley tend to have extreme honey and brood production during crop blossoms but can suffer in the off season while the urban areas tend to have a more consistent food source availability throughout the foraging period (March - November) due to urban landscaping and irrigation.  
     The honey frames should be positioned on both sides of the cluster in the bottom box and above the cluster in the second super (super = hive box).  If the cluster is in an upper box it's recommended to switch the box to the bottom in preparation for winter.  In the spring you can reverse that process as the girls will have worked their way up to upper part of the second box.

Winter cluster at the end of winter

      For a Kenyan Top Bar put the cluster at one end and the honey frames next to the cluster.  I've often run all deep supers in my Langstroth hives because universal boxes and frames are easier to manage.  I can add honey frames from my third or fourth box to the brood boxes to over winter.  Many new beekeepers and some old are moving towards all medium boxes because of the lighter weight.  This makes sense as a deep box of honey can weigh 80 lbs (36 kgs).
      All beekeepers have plus and negative food accumulation months and generally April 1 to Oct 1 are positive food accumulation months for us in Vancouver.  March and October can be neutral but are usually negative depending on the available foraging days (weather).  November through February are winter cluster, negative food accumulation months.
Pest and Disease Control      
     Pest and disease identification and control should be an ongoing process and if you are beginning now it may be too late.  Evidence of chalk brood or nosema would indicate a weak colony (Honey Bee Diseases and Parasites).  Increased ventilation and removal of old comb can be done to combat the chalk brood and a pollen patty/fumagillin mixture may help combat the nosema.  Mite counts throughout the year and subsequent treatments should let you know whether you have a major issue.  Mite treatments like formic acid can continue into October as long as there is a day time high temp of 10c and although oxalic acid was traditionally done in December when there is little to no brood present (it does not effect mites in the brood) it is now a year round treatment option.  A mistake made by many beekeepers is to treat in August and with a large, healthy colony and assume everything is fine.  Continue mite tests and treatment through September.  If needed I will start my final formic acid treatment in the middle of September.  A reduced screened entrance using eighth inch hardware cloth can be used to allow for needed ventilation during formic acid treatments while providing a more easily defended (against wasps) reduced entrance.  I staple the eighth inch hardware cloth to the bottom board and first brood box.  I find this a necessity as the yellowjacket wasps are very aggressive starting in August.   
     The video below "Getting Your Hives Ready for Winter" is a recorded webinar with Kim Flottum (Bee expert and editor of Bee Culture magazine) which does a very good job of discussing winter preparation for bee colonies focusing on year around mite control.  Controlling mites goes a long way to controlling virus transmission and overall colony health.


Cold and Moisture
      The U.S. Bee Informed Survey of wintering hives (the only large scale North American winter survival survey) showed that only 3 conditions determined winter survival success and they were adequate food, strong colonies (equalization or combining hives) and ventilation (moisture reduction).

The survey is extensive and includes the results for geographic region, all types of pest and disease management, feeding and winter preparation.  The Bee Informed Survey 2016 - 2017

     Wrapping and insulation showed no benefit but I think that depends on where you live.  If you live in cold northern climates like Winterpeg either you wrap and insulate or you bring the girls inside. 40 below is 40 below.  While insulation is not traditionally necessary in Vancouver (we have a mild winter climate and rarely get much below freezing) I know some that do with good results.  Insulation could be counter productive by keeping the heat out and preventing the hive from warming up by the sun (Sun in Vancouver in winter?).  However,  insulation under the outer cover is effective at minimizing the temperature difference and resulting condensation between the outside and inner hive (With half inch R5 insulation no moisture and mold, without both).  Some local beekeepers wrap their hives with black roofing paper to prevent wind penetration and to help absorb the heat (Black objects absorb more heat).   It may be helpful but an argument against this is that the girls take care of  wind penetration with use of propolis and do we want a warmer hive in the winter?  Warmer means more active bees and more food consumption.  For us wrapping in March may be a good option as we have lots of blossoms (Willow, forsythia, flowering cherry, bulbs ...) but marginal foraging temperatures.  Wrapping would warm the hives and get the girls flying earlier in the day increasing their pollen and nectar intake and stimulate egg laying.  This winter with a prolonged forecast of -12 Celsius (10 Fahrenheit) I insulated and wrapped the hives.  Over the 2 week period we had cold temps and high winds.  Sunny and 6 Celsius (43 Fahrenheit) today I checked the hives and all were well and active with lots of cleansing flights (poop breaks) and house cleaning (removing dead bees).  One particularly strong 8 frame cluster came to greet me in an unfriendly manner when I added the candy board.     

Temperature difference on black and white surface
     Wintering your bees is like real estate value in that the 3 most important considerations are location, location and location.  Location dictates the methods you will use to protect your bees from the elements. Windbreaks are essential in some areas where there are cold, winter winds, especially for rooftop beekeepers.  In winter Vancouver has a predominant, low pressure weather pattern with winds from the southeast that bring with it fairly constant cool, wet weather.  We have only a few snow falls per year and a few weeks of freezing temperatures.  Therefore moisture, not cold is our biggest issue.  The moisture is created when warm air created by the cluster of bees rises and contacts the cold inner cover creating cold condensation which drips onto the cluster.  There are a lot of different methods to reduce moisture in the hive from dripping on the cluster like tilting the hive forward by putting a 2x4 under the back of the hive to allow the moisture to run down the front of the hive and not on the cluster and/or as mentioned above insulating under the outer cover.  Another option is an Insulated Moisture Quilt placed above the hive boxes to reduce cold condensation dripping on the winter cluster.
The bee hive in winter without any form of moisture reduction

Insulated Moisture Quilt

     The heat produced by the cluster rises to contact the warmer insulated cover producing less condensation, which then drips onto the wood chips (not the bees) which are dried by the vent holes.  They are easy to make out of scrap material and the link above provides detailed building instructions.  
     During winter you must have an upper entrance in your Langstroth hive for ventilation and because dead bees or snow can block the lower entrance. For moisture reduction in a Kenyan Top Bar Hive beekeepers can use an insulated moisture quilt, carpet over the top bars (Bill Stagg's method) or reflective insulation (Sam Comfort's method).  Whether you leave your screened bottom board open or not (for increased ventilation) is debatable but if left open you must block the drafts from blowing under the hive.  I put the mite test board in to block the winter winds but have friends who do not and successfully overwinter their bees.  
     In Vancouver we get at least 2 major storms a year of 80+ km winds (50 miles per hr).  For this reason and the presence of skunks and racoons we use cinder blocks (ratchet straps are another option) on our hives to prevent the outer cover from blowing off or being removed and have positioned the hives to have a natural wind break (berm to the south).  A wind break is particularly important for roof top beekeepers.  Though not necessary some of us use pieces of plexiglass extending 4+ inches over our outer covers to provide additional weather protection and extend the life of our beekeeping equipment.

 Winter Hive

      With the decrease in available forage robbing and wasp attacks become a real concern starting in August so guard bees will become more defensive and in the wild the colony may reduce the size of the entrance with propolis and wax.  The beekeeper can assist by reducing the entrance to as small as 1.5 centimeters or a half inch to make it easier to defend (weaker colonies).  In Vancouver wasps have been more aggressive, longer into the winter over the last few years.  I received a swarm call recently in December.  There had been a few hard frosts so out of interest (knowing it wasn't a swarm)  I went to see a very active paper yellowjacket nest in an unheated crawl space.  The Yellowjacket wasps and to a lesser degree Bald Faced Hornets are usually aggressive in our apiary starting in August, attempting to enter hives and picking off stray bees at the entrance.  This year I used eigth inch cloth as an entrance reducer to allow for mite treatment.  This blocks potential wasp intrusion and robbing by other bees if you are feeding and still allows ventilation. The girls are better able to defend the reduced single entrance.  Wasps will stay active at cooler temperatures than your bees so when the girls are in cluster the wasps may enter the hive.  I don't indiscriminately kill wasps (I've identified 9 different types in our garden including a parasitic wasp in my blue mason and leaf cutter bee cocoons) but have found them increasingly aggressive towards our colonies for a longer period of time in the fall (last year until December).  I've found the pheremone lure variety wasp trap to be very effective on our greatest threat which are the common Yellowjacket wasps (does not attract Bald Faced Hornets).  This lure trap can also be used in the spring to kill the emerging wasp queens.  The Rescue brand lure variety works well but the bait only lasts for about 5 days so can be expensive.

Wasp trap
You can also make your own wasp trap.  Here is a study from the University of Athens showing the effectiveness of 3 different types of traps (Wasp Traps).  Maybe the easiest and most popular is the pop bottle trap.  We have a number of these out now with a 50/50 mixture of sugar and water and a capfull of vinegar poured in the entrance to keep the bees away.  They have worked well but you need to add a capfull of vinegar occasionally to dissuade the bees.  Here is a study from the University of California on the effectiveness of different baits (Baits for the Control of Yellowjackets).  I've not had much success with fish or meat baits  later in the summer.  These protein baits are successful earlier in the season when the wasps are feeding their brood.  Wasps prefer a sugar and water bait at this time of year.  For more information on wasps go to the Wasp section of our Beekeeping Library.

  If wasp attacks or robbing persists and they gain access to your hive you can use a robber screen which are easy to make.

     Due to the homeless camp next to our hives last year we had a noticeable increase in our ground tunneling rat population this year which I believe resulted in a decrease in ground nesting yellowjacket wasps.  Charles Darwin and his children studied ground nesting bumble bees and found that the population of bumble bees was dependant on old maids who kept cats who killed the rats allowing for greater bumble bee ground nesting success.  We don't have any cats though this summer a pair of Sharp-shinned hawks moved in to help with the over population of rats.     

Equalization, Combining Colonies or Requeening     
      It is recommended that new beekeepers have 2 hives rather than 1 because inevitably one will be stronger than the other.  This allows you to strengthen the weaker hive with bees from the stronger colony (Equalization of Bee Colonies Strength by Khalil Hamdan) or to split the stronger hive if you lose the weaker colony.  Though this can be done in the spring it can also be done in preparation for winter by adding 2-3 frames of bees and brood as needed.  However, if you have a weak colony it's likely you have a sick colony or weak queen which would suggest treatment and/or requeening. You can also combine the weaker colony with a stronger one using the newspaper method (Uniting Honey Bees by David Cushman).  Although some will insist it imperative to kill the weaker queen others like the late, great David Cushman suggest that it is not necessary: "Many texts will tell you to kill the least desirable queen in one of the two groups to be united, but I find it is often prudent to leave both queens, so that the bees can make the choice, in most cases the younger and fitter queen remains, but there may be subtle things in a queen's make up that the bees are better able to make choices about rather than the beekeeper (David Cushman)." 

The newspaper method of combining hives

     In October most beekeepers reduce their Langstroth hives to 2 deep supers (3 mediums) and Kenyan Top Bar hives are reduced by moving your follower board or your false backs forward (Winterizing your Top Bar Hive).  Queen excluders should be removed so the queen can move with the cluster as it moves upward

      Though still mild it's time to think of mice which like to winter in the hives. There are a hundred different varieties of mouse proof entrances from quarter inch screened mesh, drilled metal sheet to simple nails minimizing the entrance.  The mice can get through a fairly small area and will chew through wood.  I use a simple wood entrance reducer with a nail reducing the entrance to just over the width of a bee.  This allows for the removal of dead bees which the girls do as part of winter house cleaning.  If you find the mice chewing on the entrance reducer you can wrap it in wire mesh.  Here is an easy step by step guide to making a mouse guard from Brooksfield Farm just south of us near Mt. Baker.

Difficult house cleaning
Wire mesh mouse proof entrance reducer
     For more information on wintering your colonies check out the recorded webinars by Kim Flottum, "Getting your hives ready for winter" or "Putting the hive to bed for winter".  You may also want to check out The Biology and Management of Colonies in Winter , Winterization Guide for Beekeeping , The Thermology of Wintering Honey Bee Colonies or Wrapping a Honey Bee Colony with Tar Paper  from the "Winter Management" section of the Beekeepers' Library.  Good luck to you and your bees and stay dry.