Why Winter Preparation Starts in August
The most common mistake beekeepers make about winter preparation is starting too late. The "winter bees" — the long-lived individuals that carry the colony through until spring — are raised from August through October. These bees need to emerge healthy, full of fat bodies (stored proteins), and free from mite damage. That means the work that determines winter survival is done in late summer, not November.
Think of winter preparation as a three-phase process: August–September (varroa treatment, nutrition), October (final checks, insulation), and November–January (minimal disturbance, emergency monitoring).
Phase 1: Late Summer (August – September)
Step 1: Treat for Varroa — This Is Non-Negotiable
This is the single most important action of the year. Remove all honey supers first. Then treat immediately with oxalic acid vaporisation (3 treatments, 5 days apart), formic acid strips, or thymol — whichever is appropriate for your current temperatures.
Target: below 0.5% mite load (fewer than 1 mite per 200 bees on an alcohol wash) before the last round of winter bees are capped. Test again in early October to confirm the treatment worked. If still above 1%, re-treat immediately — you still have a narrow window before winter bees are all laid.
Step 2: Assess Honey Stores
Minimum requirements for winter survival vary by climate and colony size. As a general guide for temperate Europe:
- Colonies in Langstroth hive on 10 frames: minimum 18–22kg honey
- Colonies in National (UK): minimum 15–18kg
- Smaller regional hive types: scale proportionally
Heft the hive from behind. If it feels surprisingly light, weigh it. A frame of capped honey weighs approximately 2.5–3kg. Calculate your deficit and feed immediately with thick 2:1 sugar syrup (2 parts sugar to 1 part water by weight). Bees convert this slowly so feed early — all syrup should be in the hive and capped by mid-October at the latest.
Step 3: Confirm Queen Status
Open each hive on a warm September day and confirm a queen is present and laying. A colony that enters winter queenless — or with a failing queen — is dead by February. Look for eggs and young larvae in the centre frames. If you find a patchy pattern or no eggs, investigate and rectify before temperatures drop.
Step 4: Reduce to One Box
Most colonies in temperate climates should winter on one box. Remove any supers with minimal stores — consolidate into the single brood box (or double brood box for very large colonies). A small cluster trying to heat two boxes will fail; a cluster correctly sized for one box maintains warmth efficiently.
Phase 2: Autumn (October)
Step 5: Reduce the Entrance
Install entrance reducers to approximately 4–6cm. This helps maintain heat, prevents mice from entering (critical — a mouse inside a hive by October will destroy entire combs before spring), and reduces robbing as foraging opportunities diminish.
Step 6: Mouse Guards
A metal mouse guard with 9mm holes is an inexpensive but critical piece of equipment. Mice enter hives in October and nest over winter, destroying comb, wax, and stores. Fit guards before temperatures drop to single figures at night. Remove guards completely in April when colonies start flying regularly.
Step 7: Insulation and Ventilation
Bees do not need to be warm — they need to be dry. Moisture is a greater killer than cold in most temperate climates. Ensure the hive has adequate top ventilation (a small mesh insert or slightly raised crown board) to allow moisture from the cluster's respiration to escape upward. A single sheet of polystyrene insulation above the crown board retains heat while allowing vapour to move through the top ventilation.
Open-mesh floors left fully open during winter increase ventilation but reduce heat retention. In very cold climates (below -10°C for extended periods), partially blocking the mesh floor improves winter survival.
Step 8: Woodpecker Protection
Green woodpeckers are a significant hive predator in many parts of Europe from October through March. They drum through thin hive walls and consume clustering bees. Wrap hives in chicken wire or purpose-made woodpecker guards if you are in an area with woodpecker activity.
Phase 3: Winter (November – March)
Minimal Disturbance
Resist the urge to inspect. Opening a hive in winter breaks the propolis seal, chills the cluster, and disturbs the bees in a way that has real costs to colony survival. Heft the hive weekly to check for weight — a hive that becomes noticeably lighter over 2 weeks needs emergency fondant placed directly on the top bars.
Emergency Winter Feeding
If a colony runs low on stores mid-winter, fondant (solid sugar) can be placed directly on the top bars above the cluster. Unlike syrup — which bees cannot process in cold weather — fondant is accessible to the cluster cluster at any winter temperature. Keep 2–3kg of fondant on hand from October onwards as insurance.
Record Everything
Note your heft dates, any interventions, and colony behaviour through winter. Colonies that consistently struggle in winter tell you something about their varroa treatment timing, queen quality, or store levels. Seasonal records, tracked over years, reveal patterns that let you make smarter decisions each autumn.