Winterising Your Apiary: How to Prepare Hives for a British Winter

Winter doesn't begin for a colony on the shortest day. For a British hive it starts somewhere around the middle of September, when the last of the ivy has been worked and the bees are quietly deciding how many of themselves to keep alive until March. Almost everything that decides whether a colony comes out of the cold in good shape — the stores in the box, the mites on the bees, how dry the hive stays — is settled in the few weeks before the clocks change.

That is the encouraging part. Winterising is not one long job on a wet Saturday. It is a short, ordered sequence of tasks, most of them done while the weather is still mild enough to open a hive without doing harm. Get the sequence right, and the winter itself becomes a matter of leaving the bees alone and paying attention from the outside.

Feed early, and finish before the cold arrives

Autumn feeding is the job that cannot be allowed to slip. Once the supers are off, feed thick syrup — roughly two parts sugar to one part water by weight — or a good invert syrup, which the bees take down with less work and less risk of fermentation. The aim is to have the feed processed and capped while daytime temperatures are still high enough for the colony to work properly.

Leave it too late and the syrup sits in the feeder, or sits uncapped in the brood box, where it can ferment and give the bees dysentery at exactly the wrong moment. A full colony generally needs somewhere in the region of 15–20 kg of stores to carry it from October to April. A brood box well filled with capped stores is a sensible benchmark; an extra frame of honey is far better than an emergency in February. Hefting the hive from the back with one hand tells you a lot — if it feels light and hollow, keep feeding.

When the bees stop taking syrup down, stop offering it. From late autumn onwards, feed fondant instead. Placed over the crown board hole in a container the bees can reach, it adds weight without adding water, and it keeps for weeks.

Deal with varroa before the winter bees are sealed

The bees reared in late summer and early autumn are the ones that will carry the colony through to spring, and they need to be as healthy as possible. Once the supers are off, treat according to what is authorised for use in the UK and appropriate to the time of year. Thymol-based products need mild weather to work well, which rules out November. Oxalic-acid treatments are generally used during the broodless period in midwinter, when there is little sealed brood to shelter mites.

Follow the label exactly — dose, temperature, timing and any restrictions. Put an insert board under the mesh floor for a few days afterwards and count the mite drop, so you know what you started with and whether the treatment did its job. If you are unsure which product suits your situation, your local association is a better source of advice than a forum argument.

Fit the mouse guards and tidy the stand

A single field mouse can move into a hive, chew through comb and settle in for the winter, and a colony sharing its home with a rodent rarely thrives. Fit mouse guards by early October, with holes small enough that a mouse cannot squeeze through — around 9 mm is the usual guide. Keep the entrance reduced as well, which helps against late wasps and robbing while the colony is small.

The stand matters more than people expect:

• Set hives well clear of the ground, around 30–40 cm, so the floor stays drier and slugs have less cover.
• Cut back long grass and brambles that hold damp air against the entrance.
• Tilt the hive very slightly forward so any water that gets in runs out of the entrance rather than pooling on the floor.
• Strap or weight the roof in exposed sites. A gale that shifts a roof lets in rain, and a wet hive is a dead hive.

Insulate the top, keep the air moving

Bees do not heat the box; they cluster and keep the middle warm. Insulation helps them do that on less food. An insulated roof, a slab of rigid insulation above the crown board, or a wrapped cosy all reduce heat loss and, just as importantly, keep the underside of the roof warm enough that water does not condense there.

Damp is the real enemy

In a British winter, cold rarely kills a strong colony. Damp does. Warm, moist air rises from the cluster, meets a cold surface, condenses, and drips back onto the bees. A wet cluster loses heat quickly and often ends up with dysentery. So combine insulation above the bees with ventilation above the insulation: an open mesh floor with a baffle to cut draughts, and a small top vent — a matchstick under a roof corner, or an insulated roof with a built-in vent — so moisture has somewhere to go. Whatever you do, do not wrap a hive in plastic sheeting and call it protection. That traps moisture in and does more harm than good.

Monitor from the outside, not the inside

Once the colony is buttoned up, your job is observation. Lift the back of the hive every couple of weeks with one hand and compare it with last time; a hive that has suddenly lost its weight needs fondant now, not in a fortnight. Watch the entrance on mild days. Bees will take cleansing flights when the temperature lifts, and they will clear out dead ones. On a bright afternoon in February, a quick look under the roof to check the fondant is fine. Breaking the cluster apart is not.

After every gale, walk the apiary and check the roofs, straps and entrances. Mouse guards can silt up with dead bees and debris, and a blocked entrance on a mild day is a serious problem. Clear it with a stick and move on. As a rule, avoid opening hives when it is below about 10°C unless something is clearly wrong.

A calm winter, and a ready February

Work through the tasks in order and then leave them to it:

1. Supers off, autumn feed finished and capped.
2. Varroa treated and mite drop monitored.
3. Entrance reduced, mouse guard fitted.
4. Insulation above the cluster, ventilation above the insulation.
5. Roof secured, hive tipped slightly forward, grass cleared.
6. Stores hefted, fondant and a spare feeder waiting in the shed.

February and early March are when colonies most often starve. Brood rearing starts, consumption rises sharply, and the stores that looked ample in November can vanish. Keep hefting, keep fondant to hand, and take advantage of the first genuinely mild days to check that all is well. Do that, and the hardest part of winterising is knowing when to do nothing at all.

Photo: suju-foto / Pixabay