Winter feeding: the weight figures you should keep an eye on

Why weight is decisive in winter

Winter is a demanding time for bee colonies. In summer a beekeeper can look in on the bees practically every day, but in frost and snow, check-up visits are not only a chore, they are often counterproductive.

Every time the hive is opened in winter it costs the bees valuable energy that they urgently need in order to survive. The winter cluster, into which the colony draws itself together, must not be disturbed.

But this is exactly where many beekeepers face a dilemma: how can you be sure that your colonies have enough feed without having to keep looking?

The answer lies in the weight of the hive. A bee colony uses feed continuously through the winter, and that consumption can be tracked precisely by monitoring the weight - without ever having to open the hive.

Weight monitoring in winter is not a new invention, but modern hive scales make it considerably easier and more precise today. Beekeepers used to have to heave their hives up and estimate the weight by hand. Today digital systems make continuous monitoring possible, which not only saves time but, above all, saves colonies.

Because winter losses caused by a lack of feed can be readily avoided with the right monitoring.

The right starting weight in autumn decides how the winter goes

Preparing for winter does not begin in December, it begins in autumn. The starting weight your colony puts on the scale in October or November largely decides whether it comes through the winter well.

Important: the weight figures given in this article are expressly meant as orientation, not as absolute reference values. Every apiary has its own particularities, and they affect hive weight considerably.

Rough figures by hive type (examples!)

• Dadant/Zander: example optimum 40-45 kg, example minimum 35-40 kg, feed share 15-18 kg
• Deutsch-Normal: example optimum 35-40 kg, example minimum 30-35 kg, feed share 12-15 kg

These are average figures and may differ considerably at your own apiary! The actual weights depend on a number of factors, which we will go through in detail in a moment.

Why absolute figures can mislead

The trouble with fixed weight figures: they suggest a precision that does not exist in practice. Two Dadant hives holding an identical amount of feed can easily differ by 5 to 10 kilograms - and both colonies are nonetheless perfectly well supplied.

The reason lies in the many variable factors that affect the total weight. The hive material makes a considerable difference: a solidly built hardwood hive weighs several kilograms more than a light polystyrene one. The number of frames in the brood chamber varies considerably depending on how you work - with Dadant there may be between 6 and 12 frames hanging in the hive over winter, and each drawn frame already weighs about 500 grams empty. That factor alone can account for a difference of 3 to 6 kilograms.

On top of that come further influences. Some beekeepers put stones on the hive roof so that it does not blow off in a storm - that is easily 2 to 5 kilograms of extra weight. Colony strength plays a part too: a strong colony with a lot of bees weighs more than a weaker one. Geographical location also affects how much feed is needed - in cold regions colonies need larger reserves than in milder areas.

That is why it is absolutely essential that, in your first year of weight monitoring, you work out your own reference values. Note down the starting weight in autumn, when you are sure that your colonies are sufficiently supplied. Watch how the weight develops over the winter. And keep those figures in mind for your particular way of working, your hives and your site. These individual reference values say far more than any general table.

How to work out your own empty weight - the basis for everything else

The key to successful weight monitoring is knowing the empty weight of your hive. With that figure you can work out precisely, at any time, how much feed is still there - regardless of all the other factors.

The best time to work this out is the autumn inspection after feeding up, typically in mid to late September. By then the conditions should not change any further: the number of combs is settled, extra boxes have been removed or added, queen excluders and other components are in their final winter position.

The method is simple:

1. Weigh the complete hive (e.g. 45 kg)
2. Estimate the amount of feed during the inspection (e.g. 18 kg)
3. Calculate: empty weight = total weight - feed = 27 kg

This empty weight of 27 kg is now your personal reference for that particular hive. It includes everything: wood, frames, wax, propolis, bees, pollen, any stones weighting the roof - simply everything apart from the winter feed.

Why does that figure matter so much? Because from now on you know at any time how much feed is left. If the scale shows 35 kg in January, you still have 8 kg of feed (35 - 27 = 8). If the weight falls to 30 kg, only 3 kg of feed is left - time to act.

Modern digital hive scale systems such as Honeylink can store that figure as a tare, or you can set a warning level just above the empty weight (for instance at 30 kg for a warning when only 3 kg of feed is left). That way you are notified automatically, long before the feed becomes critical.

This is how much feed your bees use in winter

The feed consumption of a bee colony in winter is not constant, it varies considerably from month to month and with the weather. Understanding those variations is essential for keeping track of the feed.

Feed consumption at a glance

• Nov/Dec: 0.5-1 kg per month in mild weather, 1-1.5 kg in cold weather (about 0.15-0.35 kg per week)
• Jan/Feb: 1.5-2 kg per month in mild weather, 2-3 kg in cold weather (about 0.4-0.7 kg per week)

A simple rule of thumb: colonies that are not raising brood use about 1 kg a month, colonies that are raising brood about 3 kg a month - the latter depending heavily on how much brood there is.

November/December: consumption is still comparatively low. In mild weather an average colony uses about 0.5 to 1 kilogram a month - that comes to only about 150 to 250 grams a week.

January/February - the critical phase: temperatures often drop to their lowest, and at the same time many colonies are already starting the first brood. The energy requirement rises to 1.5 to 3 kilograms a month (about 400 to 700 grams a week). It is in exactly this phase that most colonies starve, because beekeepers underestimate the rising consumption.

When does it become critical? These thresholds you need to know

The crucial question is not only how much your bees use, but when you have to step in. Instead of working with fixed absolute figures, you should go by relative thresholds that build on your own base weight.

Critical thresholds - work them out for yourself!

The right way: first work out your individual base weight - that is, the weight of a well-supplied hive in autumn for your particular way of working. From that figure you then calculate the critical thresholds.

Example for a typical Dadant hive with a base weight of 42 kg:

• Early warning: base weight minus 7-10 kg = about 32-35 kg
• Critical: base weight minus 12-15 kg = about 27-30 kg

Example for a Deutsch-Normal hive with a base weight of 36 kg:

• Early warning: base weight minus 6-9 kg = about 27-30 kg
• Critical: base weight minus 11-13 kg = about 23-25 kg

Why relative rather than absolute?

If you work with absolute figures (e.g. "critical below 30 kg"), that can be dangerous. Imagine that your Dadant hive, with its heavy wooden construction, 12 frames in the brood chamber and a stone on the roof, has a base weight of 48 kg instead of the "typical" 42 kg. A weight of 32 kg - still in the "early warning range" according to the table - would in truth already be critical, because you would have used up 16 kg of feed by then!

The other way round holds too: a light polystyrene hive with only 8 frames might have a base weight of 38 kg. At 32 kg everything would still be fine here.

The rule of thumb is therefore:

• Early warning: when you have lost 7-10 kg from the starting weight (with Dadant/Zander) or 6-9 kg (with Deutsch-Normal)
• Critical: when you have lost 12-15 kg from the starting weight (with Dadant/Zander) or 11-13 kg (with Deutsch-Normal)

Once the early warning threshold is reached you should prepare for emergency feeding over the next two to three weeks. Get hold of feed candy or fondant, and plan a mild day for the feeding. In the critical range you should give emergency feed within a few days.

Reading the weight curve: what is normal, what is a warning sign?

A hive scale gives you not just individual weight readings but, above all, the course of the weight over time. Interpreting that curve is an art in itself, but one you will pick up quickly. A healthy winter curve shows a slow, steady loss of weight from November to March. It starts in November at your individual starting weight (typically between 35 and 50 kilograms, depending on how you work) and then falls gently and evenly. The curve is not a straight line; it shows a slight acceleration as the winter goes on, particularly from February, when brood rearing sets in.

What you should not see in a healthy curve are sudden drops or unexplained jumps. The weight loss should be even, a little less day after day. That evenness is precisely the sign that all is well with your colony. The bees are sitting quietly in the cluster, using their feed as expected, and nothing is disturbing them.

Three warning signs you should spot straight away

First warning sign - weight falling too fast: if your colony is losing distinctly more than the figures given above - that is, more than 400 grams a week in December, or more than 800 grams a week in January/February - something is wrong. The causes can be various. Perhaps your colony is very strong and correspondingly uses more feed. There may be unrest in the colony, caused by disease or queenlessness. Or your hive is poorly insulated, so the bees have to put more energy into holding the temperature.

Second warning sign - plateaus: if the weight stays level over several weeks, or even rises slightly, that is confusing at first. In many cases it is a good sign and simply means that the weather is mild and the bees are still bringing in pollen or water. But take care: there may also be a measurement error, from snow on the hive for instance. In such cases, check whether the scale is being distorted by something outside the hive.

Third warning sign - sudden drops: if your colony loses more than two or three kilograms within a few days, that is unusual. Possible causes: the colony may be badly weakened, or there is some other problem. In that case you should plan a careful check-up visit during the next mild spell. Open the hive only briefly and see whether there is still life in there.

Emergency feeding in winter: which feed and how much?

If your weight monitoring shows that your colony is getting too light, you have to act. But not every feed is suitable in winter, and both the timing and the type of feeding decide between success and failure. In winter there are essentially three options for emergency feeding, each with its own advantages and disadvantages.

The gentlest and safest method is feed candy. Candy has the great advantage that it contains no liquid and therefore causes no condensation in the hive. You can give it without any trouble even in frost, and the bees take it as they need it, without any stress. Lay one or two kilograms of candy directly over the seams between the combs, so that the bees can reach it easily. Check every two or three weeks whether there is still enough, and top it up as needed. Candy is the winter feed of choice for experienced beekeepers.

The second option is fondant, which also works well and is easy to handle. Fondant keeps well and can be laid straight onto the top bars in handy 2.5-kilogram packs. The drawback is that fondant can go hard in very cold temperatures, so that the bees have difficulty taking it. Even so, fondant is a proven alternative to feed candy and is preferred by many beekeepers.

The third option, liquid feed, is on the whole to be treated with caution in winter. You should only give liquid feed when temperatures stay above ten degrees Celsius for several days and there is no risk of frost in the days that follow. The reason is simple: damp in the hive can become a death trap when the frost returns. The bees cannot dry the damp out, condensation forms, and the winter cluster is put at risk. Liquid feed belongs to summer feeding, not to winter.

Practical tips: how to monitor the weight properly

Theory is one thing, practice another. How often should you weigh? What can go wrong? And what do you do if you have no digital hive scale? Many beekeepers ask these questions, and the answers are simpler than you might think.

The most important tip is regularity. In the early winter months of November and December it is enough to take a look at the weight every two weeks. Feed consumption is still low in that phase, and big surprises are rare. From January onwards, though, you should switch to weekly checks. Now the situation becomes more critical, and you want to be able to step in in good time.

With a digital hive scale this work takes care of itself - you see the trends in real time on your phone. Without a hive scale you have to do it by hand: lift the hive carefully, weigh it with a spring balance or, at a pinch, a bathroom scale, and note down the result.

One thing many beekeepers underestimate is the effect of the weather on the weight reading. Snow on the hive can mean a considerable amount of extra weight. Even five to ten centimetres of snow puts two to five kilograms on the scale that have nothing to do with the actual state of your colony. After snowfall you should therefore interpret weight readings carefully, or clear the snow off the hive. The thaw is trickier still: it produces an apparent loss of weight even though all is well with your colony. Rain can distort the reading too, particularly with wooden hives, which take up moisture and become heavier as a result.

If you are working without a digital hive scale, a simple table is very helpful. At each weighing, note down the date, the weight, the difference from the last reading, the weather conditions and the action you took as a result. That way you can see at a glance whether your colony is within the normal range or whether something needs doing. Such a table also helps you to build up experience over the years and to get to know your own colonies better.

How digital hive scales make winter monitoring easier

A digital hive scale fundamentally changes the way you bring your colonies through the winter. Instead of driving out to the apiary every week or two in all weathers and weighing by hand, you have the weight history of your colonies on your phone at any time. This continuous monitoring is not only more convenient, it is above all safer for your bees. You spot problems earlier, you can feed more precisely, and you never have to open the hive to look at the feed.

The tare function: using the empty weight as a reference

Probably the most important function of modern hive scale systems is the ability to store the empty weight of your hive as a tare. If you have worked out the empty weight in autumn as described above (say 27 kg), you can save that figure in the system. From that moment on, the scale no longer shows you the total weight but the available amount of feed directly.

A practical example: your hive weighs 45 kg in total, the empty weight is 27 kg. Once the tare function is switched on, the system shows you 18 kg - which is exactly the amount of feed. In January the reading falls to 12 kg, in February to 8 kg. You see at a glance how much feed is left, without having to do any arithmetic.

This approach has one decisive advantage: it removes all the uncertainty about hive weight, material, number of frames or stones on the roof. All those factors are already accounted for in the empty weight. You concentrate solely on what matters: how much feed does my colony still have?

Intelligent warning levels instead of blanket figures

Modern systems such as Honeylink let you define your own warning levels. Instead of working with blanket thresholds such as "critical below 30 kg", you set your alarms on the basis of the actual feed reserve.

Recommended warning levels with the tare function switched on:

• Early warning: at 6-8 kg of feed remaining - you still have time to react calmly
• Critical warning: at 3-5 kg of feed remaining - now you should feed promptly

Alternatively, if you do not use the tare and work with absolute weights, you can set a warning level just above your empty weight. With an empty weight of 27 kg you would, for instance, get a warning at 30 kg (equal to 3 kg of feed left) or at 32 kg (equal to 5 kg of feed left).

Intelligent alarms and consumption patterns

The greatest advantage of modern hive scale systems lies in the intelligent alarm function. The system learns the normal consumption pattern of your colony and notifies you automatically when the weight loss is unusually fast, when there are sudden changes, or when the thresholds you have defined are crossed. You no longer have to open the app every day and interpret curves - the system gets in touch when something needs doing. That gives you peace of mind and at the same time saves an enormous amount of time.

Remote access is particularly valuable for beekeepers with several sites or with colonies a long way off. You check your bees from the sofa, only drive out to the apiary when it is really necessary, and monitor several colonies at once without ever having to be there. In winter especially, when journeys through snow and ice are a chore, that is an invaluable advantage. You will find more information on modern hive scale systems at www.honeylink.io.

The most common mistakes in winter feeding

Even experienced beekeepers make the same mistakes again and again when it comes to winter feeding. In the worst case these mistakes can cost whole colonies, but they are all avoidable once you understand how things fit together.

The most common and most serious mistake is reacting too late. Many beekeepers wait until the colony is acutely starving before they step in. By then it is often too late. The bees are weakened, the queen possibly dead, and even if you feed now the colony will not recover. The remedy is simple: react as soon as the early warning threshold is reached. Get feed ready as soon as your colony has lost 7 to 10 kilograms from its starting weight, not only when it has lost 12 to 15 kilograms. Those few days' head start give you more room to manoeuvre.

The second common mistake is opening the hive in winter. Many beekeepers think they will just take a quick look. Every opening of the hive in winter costs the bees valuable energy that they urgently need in order to survive. The winter cluster is disturbed, cold air gets in, and the bees have to heat up again. Weight monitoring gives you all the information you need. Open the hive only when you have good reason to suspect that the colony has died or is diseased, never merely to check the feed.

The third mistake is giving the wrong feed at the wrong time. Again and again beekeepers give liquid feed in frost, because they do not know any better or because they happen to have no other feed to hand. That can cause trouble: the moisture condenses in the hive, freezes when the frost returns, and the winter cluster is restricted in its movement. In winter the iron rule holds: feed candy or fondant only, never liquid feed.

The fourth mistake concerns the interpretation of the readings. Many beekeepers ignore the effect of snow load on the weight reading. Snow on the hive can mean several kilograms of extra weight, and anyone who does not take that into account draws the wrong conclusions. After snowfall you should brush the hive clear, or at least interpret the weight readings with caution. A sudden increase in weight in December very probably does not mean that your bees are busy foraging, but that there is snow on the roof.

Checklist: keeping track of winter feeding

Preparation in autumn:

• Empty weight of each hive worked out in autumn (total weight minus estimated amount of feed)
• Empty weight noted down or stored as a tare in the hive scale
• Individual starting weight established for each hive in October/November
• Warning levels set up: with the tare in use, a warning at 6-8 kg of feed left (early warning) and at 3-5 kg (critical); without the tare, a warning at empty weight + 5-8 kg (early warning) and empty weight + 3 kg (critical)
• Alternative: early warning threshold calculated (starting weight minus 7-10 kg for Dadant/Zander, minus 6-9 kg for DN)
• Alternative: critical threshold calculated (starting weight minus 12-15 kg for Dadant/Zander, minus 11-13 kg for DN)

Winter (November to February):

• Regular checking rhythm established (every 2 weeks in Nov/Dec, weekly from January)
• Feed candy/fondant in stock (with 1-3 colonies: 5 kg per colony; for larger apiaries: 10-20 kg in reserve)
• Weight table kept or hive scale installed
• Weather influences (snow, rain) taken into account when interpreting
• If the figures are critical: emergency feeding prepared

Conclusion: safely through the winter with weight monitoring

Winter losses are the greatest worry of many beekeepers, and for good reason. Every year thousands of bee colonies starve, even though they could have been saved by simple means. The good news: most losses from starvation can be avoided if you keep a consistent eye on the weight and follow the guide figures described here.

Three points are worth fixing in your mind as a beekeeper:

First, what counts is the individual starting weight: work out for each of your hives the starting weight in a well-supplied state, and use that figure as your personal reference. The guide figures so often quoted (40 kg for Dadant, 35 kg for DN) are only orientation - your own figures may differ considerably from them and still be right.

Second, you need to know the relative critical figures: if your colony has lost 12 to 15 kilograms from its starting weight (with Dadant/Zander), or 11 to 13 kilograms (with DN), that means something has to be done immediately. Do not wait another few days; give emergency feed at once.

Third, regularity is decisive: from January onwards you should weigh weekly. Only then will you spot problems in good time, before it is too late.

These basic rules, combined with a digital hive scale or at least a weight table kept by hand, will bring your colonies safely through the winter. The investment in knowledge, and if need be in a hive scale, pays for itself many times over, because losing a colony for lack of feed can be readily avoided with a little attention.

Looking ahead: attention should not slacken in February. In spring there is a risk that is often underestimated, and a second part will deal with it in detail: when cold, wet days stop the nectar coming in, it can be precisely the strong colonies, with their high feed consumption, that are affected.

Do you have questions about winter feeding, or experiences you would like to share? Write to us: info@honeylink.io

Further reading:

• FAQs on hive scales
• Part 2: The underestimated spring risk

About the author: Dr.-Ing. Frank Steyer is managing director of Honeylink and a passionate beekeeper himself. His own experience at the apiary feeds directly into product development. Honeylink has been developing digital solutions for modern beekeeping for several years - by beekeepers, for beekeepers.