Leave Enough
Part of Beekeeping
The most common cause of colony death in managed apiaries is starvation — a beekeeper who harvested too much honey and left the colony without enough to survive winter. Calculating minimum winter stores before harvest is not optional; it is the foundation of sustainable beekeeping. A dead colony represents not just lost productivity but a setback of 1–2 years (the time needed to establish a new colony to full productivity).
How Colonies Use Winter Stores
Honeybees do not hibernate. They form a cluster around the queen and generate heat by vibrating their flight muscles, consuming honey as fuel throughout winter. The cluster moves slowly through the hive as it consumes comb, and can starve even when honey remains in unreachable frames on the far side of the brood box.
Consumption rate depends on:
- Colony size: A large colony burns more food but generates heat more efficiently
- Winter temperature: Cold climates require 30–50% more food than mild ones
- Duration of cold period: The length of time when bees cannot forage (below about 10°C)
- Cluster movement: Colonies sometimes become isolated from stores by cold, dying a “cold starvation” death inches from full combs
Minimum Winter Stores by Climate
These are minimum figures — always aim for 20–30% more than the minimum to provide a safety margin.
| Climate Type | Examples | Minimum Honey Required |
|---|---|---|
| Cold (long winter) | Scandinavia, Canada, Russia | 18–25 kg |
| Temperate (moderate winter) | UK, Germany, Northern USA | 12–18 kg |
| Mild (short winter) | Mediterranean, Southern USA | 8–12 kg |
| Subtropical (brief cold periods) | Florida, Southern Spain | 5–8 kg |
These figures assume a standard-sized colony (a full Langstroth brood box with 8–10 frames well covered with bees). Smaller colonies (nucs, splits made late in the season) need proportionally less food but are more vulnerable to starvation because their cluster is small and generates less heat.
How to Assess Current Stores
The Heft Test
The simplest method requires no equipment: lift the rear of the hive with one hand, feeling its weight.
Interpretation for a standard 10-frame Langstroth:
| Heft Feeling | Approximate Stores | Action |
|---|---|---|
| Very heavy, hard to lift | > 20 kg honey | Harvest surplus or leave as is |
| Heavy, lifts with effort | 15–20 kg | Sufficient for mild/temperate winter |
| Moderate, lifts easily | 10–15 kg | Borderline — feed if cold climate |
| Light, lifts very easily | < 10 kg | Feed immediately |
| Almost no weight | < 5 kg | Emergency — colony may die within weeks |
Practice hefting your hives in late summer (August) when you know the stores are full. That muscle memory gives you a calibration point for autumn assessments.
Frame-by-Frame Inspection
For a more accurate assessment, inspect frames in early autumn (September/October before cold sets in):
- Count fully capped honey frames.
- Estimate partial frames (a half-full frame counts as 0.5).
- Total frames × 2.5 kg = approximate honey stored.
A full standard Langstroth deep frame holds about 2.7 kg of capped honey. A medium (ideal) frame holds about 1.8 kg.
| Frame Count (Deep Langstroth, fully capped) | Approximate Store |
|---|---|
| 4 frames | ~11 kg |
| 6 frames | ~16 kg |
| 8 frames | ~22 kg |
| 10 frames | ~27 kg |
Run the inspection in late September, when there is still time to provide supplemental feed before cold prevents consumption. Sugar syrup fed in October may not be processed and capped before temperatures drop — use fondant or candy boards instead.
Calculating Harvest Surplus
Simple formula:
Harvestable surplus = Total stored honey − Minimum winter requirement − 20% safety margin
Example:
- Colony stores: 28 kg (hive weighs heavily, ~10 full frames)
- Climate: temperate (UK/Germany)
- Minimum winter requirement: 15 kg
- Safety margin (20%): 3 kg
- Harvestable surplus: 28 − 15 − 3 = 10 kg
If this colony is in a cold-winter climate (requirement 20 kg):
- Harvestable surplus: 28 − 20 − 4 = 4 kg
Many beekeepers in cold climates choose to harvest nothing from their first-year colonies, ensuring the colony builds the overwinter population and stores needed for a productive second year.
Supplemental Feeding
If stores are insufficient after the honey harvest, feed before cold prevents syrup processing.
Sugar Syrup (Late Summer/Early Autumn)
Mix white granulated sugar with water. Do not use brown sugar (molasses content causes bee dysentery) or honey from unknown sources (disease risk).
| Season | Syrup Concentration | Reason |
|---|---|---|
| Spring stimulation | 1:1 (sugar:water by weight) | Thin syrup mimics nectar; stimulates brood rearing |
| Autumn feeding (food stores) | 2:1 (sugar:water by weight) | Thick syrup is faster to process and cap |
Feed 2:1 syrup in autumn in quantities of 2–5 liters per feeding session. Use a hive-top feeder or frame feeder. A colony can process approximately 1 liter per day in warm weather.
Fondant (Winter Emergency)
When temperatures are too cold for syrup to be processed (below 10°C), use fondant (baker’s fondant or homemade sugar paste):
Homemade fondant:
- Dissolve 3 kg white sugar in 1 liter water.
- Bring to 115°C (soft-ball stage) — use a candy thermometer.
- Remove from heat, allow to cool to 60°C without stirring.
- Beat vigorously until opaque and thick. Pour into molds.
- Fondant keeps for 3–6 months at room temperature.
Place fondant directly on the frame tops above the cluster (not below — bees move upward as they consume stores). A 1 kg block provides approximately 2–3 days of emergency feed for a full colony.
Candy Board (Overwinter Method)
A shallow wooden frame with hardware cloth on the bottom, filled with poured candy (same process as fondant). Sits above the cluster for the entire winter. Bees access it from below as needed. More convenient than checking and topping up fondant monthly.
Monitoring Through Winter
Even with adequate stores, check the hive once monthly on a mild day (above 8°C) without opening it:
- Heft test: Is it still heavy?
- Entrance inspection: Are dead bees being removed normally? A large pile of dead bees is normal winter cluster attrition. No dead bees for several weeks may indicate the colony has died.
- Sound check: Press your ear to the side of the hive and tap sharply. A healthy cluster responds with a brief hum. Silence suggests the colony may have died.
If a hive goes silent and feels very light in February, it has likely starved. Open carefully on the next mild day to confirm. Dead colonies should be cleaned and disinfected before being reused — store bees that starved may have been diseased.
Spring Hunger Gap
Even well-provisioned colonies can starve in early spring. As the queen begins laying in January/February (in temperate climates), brood rearing restarts and consumption spikes before forage is available. The colony burns through remaining stores rapidly.
Monitor with weekly heft tests from February onward. If the hive lightens rapidly, feed 1:1 sugar syrup or place fondant above the cluster immediately.
Leave Enough Summary
Never harvest honey without first calculating the winter stores requirement for your climate — 12–18 kg for temperate climates, 18–25 kg for cold ones, with a 20% safety margin on top. Use the heft test monthly and frame-by-frame inspection in September to assess stores accurately. Feed 2:1 syrup in autumn if stores are borderline; use fondant for emergency winter feeding when it is too cold for syrup. Monitor through winter with monthly heft tests and sound checks. The early spring hunger gap (February–March) is a second starvation risk — feed pre-emptively when colonies are actively brood-rearing before forage begins.