Come November, a British hive is at more risk from wet than from cold. Bees cope with frost; what they struggle with is condensation dripping onto the cluster, a hive that lifts like an empty box when you heft it, and a mouse that has decided the brood box is a nice dry place to spend the winter. Most of that is settled in September and October, while the bees are still flying and you can work a hive without chilling it.
What actually sees a colony through to spring
Cold alone rarely kills a strong colony. The cluster tightens, the bees shiver their flight muscles, and the outer layer of workers acts as a living duvet. The real dangers are more boring than that.
Damp is the big one. Warm, moist air rises from the cluster, meets a cold crown board or roof, condenses, and then drips back down onto the bees. A colony that is permanently slightly wet chills faster, moults into mould, and often shows signs of dysentery by February. Starvation is the second: colonies that look fine in December can be dead by March, when the queen has started laying and demand for food jumps. Third come the quiet failures — an ageing queen, a colony that went into winter too small, or winter bees that were raised while varroa was left unchecked. Deal with those in late summer and the winter itself becomes much less of a gamble.
Autumn feeding: heavy, early, and finished before the cluster forms
Feed as soon as the supers are off and the main flow has ended — typically late August into September in most of the UK. The bees need time to ripen the syrup, cap it and store it, and they can only do that while they are still active and the weather allows flying. Once they are clustered, a feeder on top is just a cold puddle they cannot reach.
Use a thick syrup for autumn stores: roughly two parts sugar to one part water by weight, mixed with hot water and cooled. Thin syrup is for spring stimulation, not winter. Feed in volume — a rapid feeder or a large contact feeder filled and left alone — rather than small amounts every few days, which encourages robbing. If wasps are still about, keep the entrance reduced and the feeder covered.
How much is enough?
The usual rule of thumb is around 20 kg of stores for a full-size colony, which is roughly a brood box packed solid plus a super, though it varies with colony size, hive type and how exposed your site is. Rather than guessing, heft the hive: lift the back edge with one hand. If it rises easily, it is light. Do this before feeding and again a fortnight later, and you will quickly learn what a heavy hive feels like.
Fondant is the winter safety net
From December onwards, syrup is useless. If a colony feels light in January or February, put a block of fondant directly over the cluster, ideally in contact with the bees through the crown board hole. Keep the roof on, disturb them as little as possible, and check again in a week or two.
Mouse guards, entrances and keeping the weather out
Field mice start looking for winter shelter in October, and a hive is prime property. Fit mouse guards by early October — metal or plastic, with holes or slots the bees can pass through but a mouse cannot. Check them regularly, because a guard blocked with dead bees on a mild day can trap foragers inside and cut ventilation.
Reduce the entrance to a couple of bee spaces for the winter. It helps the guards control the doorway, keeps draughts down and makes robbing harder. Tilt the hive very slightly forward so rain runs off the floor rather than pooling inside, and strap or weight the roof. Storms are the reason hives end up in pieces across a field in February.
Ventilation: dry air in at the bottom, moist air out at the top
An open mesh floor is usually left open all winter in the UK, with the varroa tray removed. Do not block it. Air should move gently in low and out high, carrying the colony's moisture with it. Taping up every gap in the name of warmth is a mistake; you end up with a sealed box full of damp air and a very cold, wet cluster.
The aim is not a draughty hive. It is a hive where the coldest surface is not directly above the bees. If you insulate the top properly, condensation tends to form on the walls, where it does far less harm than a steady drip onto the cluster.
Insulation: on top before around
Top insulation gives the best return for the effort. A piece of rigid foam board cut to fit inside an empty super, or under a deep roof above the crown board, keeps the crown board warm and stops the drip. Around 50 mm is a sensible thickness; more does no harm if the roof still fits and airflow below stays open.
External wrapping is optional. In an exposed site, a windbreak of netting, pallets or a hedge does more good than bubble wrap, and a breathable wrap is safer than plastic, which traps moisture. Keep the hive on a stand, clear of long wet grass, and leave the entrance facing away from the prevailing wind if you can — but not so it stays in shade all morning, since early sun gets bees flying earlier.
The October walk-through
- Finish varroa treatment in late summer, so the winter bees are raised healthy.
- Unite weak colonies and replace failing or elderly queens rather than hoping for the best.
- Remove the queen excluder, so the cluster can move up to stores in a cold snap.
- Take off empty supers and feed thick syrup until the hive is heavy.
- Fit the mouse guard and reduce the entrance.
- Clear the floor of debris and check the mesh is unobstructed.
- Add top insulation and make sure the crown board sits squarely.
- Strap or weigh down the roof, and check the stand is stable.
- Clear grass and weeds from around the entrance and make a note of the hive's weight.
Winter checks and the first warm day
Leave them alone as much as you can. Heft the hive roughly once a month, listen at the side for the low hum of a live cluster, and clear snow from the entrance so they can take cleansing flights. Dead bees on the landing board in late winter are normal; brown streaks down the front of the hive are not, and usually point to damp or unsuitable stores.
Fondant over the cluster covers most midwinter emergencies. Beyond that, resist opening the hive until a still, mild day — around 12°C or above — when you can lift the crown board for a minute and see stores and brood without chilling everything. Leave insulation in place until spring is properly established, as cold snaps in April do real damage.
If you see signs of disease you do not recognise, contact your local beekeeping association or the relevant bee health service before treating anything. Guessing costs colonies, and a second pair of experienced eyes is free.
Photo: Emanuel Chapdelaine / Pexels
