1. Priorities for the Month

• Give space in time to colonies building up rapidly.
• Look for signs of swarming impulse at every meaningful inspection.
• Use strong colonies to form artificial swarms where needed.
• Continue biotechnical varroa measures while they can still be integrated easily into colony management.
• Stay attentive to water, food stores and the effects of a return of cold or rain.

2. May at the Apiary : the guiding idea for the month

Objective Establish clearly why May is a pivotal month at the apiary: colonies develop rapidly, and the decisions taken now largely determine the rest of the season.

In May, colonies often enter a phase of very rapid development. Laying remains sustained, the brood nest expands, the population increases strongly, and the internal balance of the hive can shift in a short space of time.

The central point of the month is straightforward: accompany this build-up before it turns into congestion, a blocked brood box, or swarming impulse. In German-speaking Switzerland, this work must always be adapted to the local context: lowland, mid-altitude, aspect, weather and flowering periods do not follow the same calendar everywhere.

In other words, May is not a routine month, but a month of active observation and rapid decisions.

Further reading

• Good practice for colony inspection
• Colony management: beekeeping management plan
• Brood volume

3. Priority tasks for the month

3.1 Give space in time

Objective Prevent the colony from saturating the brood box at the moment when nectar intake and population are increasing rapidly.

What to look for
Bee density in the brood box, the actual occupation of the frames, the condition of the brood nest, the space still available for laying, and the nectar flow dynamics. Natural cues can help: depending on the region, cherry, apple, oilseed rape, or sycamore maple blossom often accompanies this phase. Full dandelion bloom can signal this turning point, without being sufficient as a reliable indicator on its own.

Practical actions
Add the super when a colony is genuinely ready, before nectar starts blocking the brood box. The decision must be based on the actual colony strength and available resources, not on a fixed date.

Points to watch
A super added too late promotes congestion and increases swarming pressure. A super added too early, on the other hand, opens up a volume the colony does not yet occupy well, especially in cool or unsettled weather.

Further reading

• Practical Guide: 4.12 Dynamic colony management
• Brood volume

3.2 Monitor and prevent swarming

Objective Detect the build-up of swarming impulse before it leads to swarm loss or a colony that becomes difficult to manage.

What to look for
Population density, congestion of the brood nest, the appearance of queen cells, a slowdown in laying, and more generally the behaviour of the strongest colonies. In May, a few days can be enough to change the situation.

Practical actions
Inspect with a clear objective, monitor powerful colonies closely, address the internal causes of swarming impulse first: lack of space, blocked laying, overpopulation relative to the available volume. If necessary, plan a more structured management measure rather than letting the swarm issue.

Points to watch
Removing queen cells without modifying the internal conditions of the colony generally remains insufficient. Catching a swarm that has already issued is sometimes possible, but it should not be the preferred strategy: in May, anticipation is what matters most.

Further reading

• Everything about swarming
• Swarm prevention
• The mechanisms of natural swarming
• Understanding swarming
• Practical Guide: 1.4.7 Increase from swarming impulse

3.3 Make use of strong colonies through artificial swarms

Objective Turn the strength of colonies into a lever for renewing the apiary, rather than letting all that momentum be lost to natural swarming.

What to look for
The vigour of the colonies, the abundance of brood, the overall quality of the queen, and the apiary's capacity to manage the nucleus colonies created.

Practical actions
Form artificial swarms when colonies are genuinely strong. In a small apiary, this simultaneously reduces pressure in the parent colony, builds up reserves for the apiary, and progressively renews queens. May is often a good window for this work, as long as the nucleus colonies still have enough time to develop well.

Points to watch
This is not about splitting mechanically. The balance of the apiary, the available equipment, the follow-up of nucleus boxes, and the capacity to manage these new units properly afterwards must all be kept in mind.

Further reading

• Practical Guide: 1.4.2 Artificial swarm
• Practical Guide: 1.4.3 Artificial swarm with queen
• Nucleus formation
• Renewing colonies and queens
• Practical Guide: 1.4 Overview of nucleus formation methods

4. Colony Health / Varroa / Asian Hornet

Objective Slow the rise of parasite pressure while biotechnical measures (drone brood removal) can still be integrated easily into spring colony management.

What to look for
Colony development, the presence of drone brood, the regularity of apiary visits, and general colony health. In May, the varroa mite population also increases with brood dynamics.

Practical actions
Continue drone brood removal when this measure forms part of the beekeeping management plan. Monitor the drone frame regularly to intervene at the right time, and integrate this work into a comprehensive varroa treatment strategy without losing sight of the rest of the season.

Points to watch
Drone brood removal does not replace the treatments and measures that will follow later. Its aim is to slow the spring dynamics of the parasite, not to resolve the varroa problem on its own. The longer one waits, the more burdensome its implementation becomes in colonies that are already highly developed and under supers.

Asian Hornet
In May, the Asian hornet's primary nest continues to develop and the first workers may appear. At the apiary, moderate vigilance is still sufficient, without falling into systematic surveillance. Traps are not recommended ; if in doubt, it is better to photograph and report the observation at frelonasiatique.ch.

Further reading

• Practical Guide: 1.4.1 Drone brood removal
• Drone frame
• Development and dynamics of bees and varroa throughout the year
• Integrated varroa control through the seasons

5. Food stores and current resources

Objective Prevent a highly developed colony from suddenly coming under stress after a few days of bad weather.

What to look for
Actual activity at the apiary, access to water, the state of food stores, pollen intake, and the general brood pattern. In May, a large colony can appear very strong and yet consume its stores rapidly once foraging flights are blocked.

Practical actions
Ensure that a watering point remains accessible nearby. Check food stores when the weather deteriorates. Read the apiary's signals in context: needs are high, but resources can vary greatly depending on the region, the current forage situation, and the duration of cold or wet spells.

Points to watch
May disease is linked to a water deficit in a context of intensive laying activity. Chalkbrood may also become more visible when colonies are exposed to chilling, dampness, or spring stress. These situations call for careful observation before drawing conclusions.

Further reading

• Practical Guide: 2.9 May disease
• Water collection and storage
• Practical Guide: 3.2 Dearth periods
• Pollen consumption and colony development

6. Depending on context: a first harvest may sometimes be on the horizon

Objective Place the spring harvest in proper perspective: possible in certain apiaries, but never a matter of course.

What to look for
The actual forage situation, altitude, aspect, colony strength, and above all the genuine maturity of the honey. Depending on the region, oilseed rape or black locust may play a role, but neither represents a general scenario for the whole country.

Practical actions
Where a spring harvest appears plausible, prepare the equipment and base the decision on the actual condition of the supers: capping, maturity, and expected quality. Elsewhere, simply continue colony management without forcing the calendar.

Points to watch
The date alone is not enough. A harvest taken too early, or decided without checking honey maturity, risks water content problems and, depending on the type of honey, crystallisation issues.

Further reading

• Honey harvest
• Controlling honey water content
• Honey crystallisation

7. In the workshop / organisation

Objective Prepare equipment and record-keeping simply but rigorously for a month in which colonies evolve very rapidly.

May calls for simple but rigorous organisation: prepare supers before they are needed, keep nucleus boxes ready should a split become opportune, monitor drone frames without delay, and record clearly what was observed at each visit.

This month tolerates improvisation poorly: colonies evolve quickly, and a missed visit can cost more than at the start of the season.

Further reading

• Good practice for colony inspection
• Inspections: points to watch
• Practical Guide: 4.8.2 Hive floor debris check
• Colony management: beekeeping management plan

8. What we do not do right now

Objective Highlight timing errors and misinterpretations that are costly in May, when colonies change quickly.

• Do not add a super simply because the calendar says so: the actual colony decides.
• Do not be content with removing queen cells without correcting the lack of space or the congestion: swarming impulse often resumes.
• Do not neglect water or food stores on the grounds that colonies appear very strong: a few days of bad weather can be enough to create a shortage.
• Do not defer the whole varroa question to summer: parasite dynamics are already building in spring.
• Do not present the spring harvest as a normal stage everywhere: it depends on local forage conditions and the genuine maturity of the honey.
   

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