By September, the transition from summer into fall is well underway across much of the U.S. Major nectar flows have ended or are beginning to taper off in many regions, temperatures are starting to moderate, and honey bee colonies are shifting their focus from summer production to winter preparation. Brood production may begin to decline, while colonies work to raise healthy winter bees and build the food reserves they will depend on during the colder months.

For beekeepers, September is a critical month for setting colonies up for winter. Honey harvesting should be winding down, Varroa mite management remains a priority, and colonies need to be evaluated for strength, food stores, and overall health. The work done now can make a significant difference in how successfully colonies overwinter and emerge in the spring.

1. Evaluate Honey Stores and Winter Food Reserves

As summer nectar sources disappear, it's important to determine whether each colony has enough food to enter the fall.

What to do:

  • Assess the amount of capped honey remaining in each colony.

  • Check colony weight or estimate available food stores.

  • Avoid harvesting honey that colonies may need for winter.

  • Identify colonies that may require supplemental feeding.

  • Continue monitoring natural nectar and pollen availability.

Why it matters:
Fall forage can become unpredictable as temperatures drop and flowering plants become less abundant. Ensuring colonies have adequate food reserves now helps prevent starvation during periods when bees are unable to forage.

2. Complete Varroa Mite Management

September is still an important time to monitor and manage Varroa mites. Colonies are producing the long-lived winter bees that will sustain the hive through the colder months, making their health especially important.

What to do:

  • Test mite levels using an alcohol wash, sugar roll, or another appropriate monitoring method.

  • Treat colonies when mite levels indicate treatment is necessary.

  • Follow all product labels and treatment instructions carefully.

  • Recheck mite levels after treatment.

  • Keep monitoring throughout the fall rather than assuming one treatment will be sufficient.

Why it matters:
Varroa mites can transmit viruses and weaken developing winter bees. Keeping mite populations under control helps colonies enter winter with healthier populations and improves their chances of surviving until spring.

3. Assess Colony Strength

September is an important time to determine which colonies are strong enough to overwinter successfully.

What to do:

  • Evaluate the adult bee population.

  • Check for a healthy, consistent brood pattern.

  • Confirm that the colony has an actively laying queen.

  • Identify colonies that are unusually weak or declining.

  • Consider appropriate corrective action for colonies that may struggle to overwinter.

Why it matters:
Strong colonies are better equipped to regulate temperature, defend their food stores, and survive periods of limited forage. Identifying weak colonies early gives beekeepers more time to address problems before winter arrives.

4. Monitor Fall Forage and Supplemental Feeding Needs

As summer blooms fade, natural forage becomes increasingly important to monitor. Some regions may have strong fall nectar flows, while others may experience a significant forage gap.

What to do:

  • Watch for incoming nectar and pollen during inspections.

  • Monitor colony weight as natural forage changes.

  • Look for signs that colonies are consuming stores faster than they are replacing them.

  • Provide supplemental feed when necessary and appropriate.

  • Continue supplying access to clean water.

Why it matters:
A sudden reduction in forage can leave colonies short on food just as they begin preparing for winter. Monitoring conditions closely allows beekeepers to supplement colonies before food shortages become a serious problem.

5. Protect Colonies From Fall Pests

As colonies become less populous and temperatures begin to cool, pest pressure can become more noticeable.

What to do:

  • Continue monitoring for small hive beetles.

  • Inspect colonies for signs of wax moth activity.

  • Remove unnecessary equipment that colonies cannot adequately defend.

  • Keep hive boxes and equipment clean and in good condition.

  • Monitor stored supers and other equipment for pest activity.

Why it matters:
Strong colonies can usually defend their comb and stored resources effectively, but declining populations can leave unused space vulnerable to pests. Properly managing hive space helps colonies maintain control of their equipment as they contract for winter.

6. Begin Reducing Hive Space as Needed

As brood production and colony populations begin to contract, September is a good time to evaluate whether colonies are occupying more space than they can effectively defend.

What to do:

  • Assess how much of the hive is actively occupied by bees.

  • Remove excess space when appropriate for the colony and local climate.

  • Consolidate equipment if necessary.

  • Make sure the colony has adequate room for its remaining food stores and winter population.

  • Avoid making unnecessary disruptions late in the season.

Why it matters:
A hive that is appropriately sized for its population is easier for bees to defend and regulate. Managing excess space can help colonies maintain a healthy environment as they transition into the colder months.

7. Prepare Hives for Cooler Weather

Fall weather can bring increasingly cool nights, wind, and periods of rain. September is a good time to begin addressing hive conditions before winter weather arrives.

What to do:

  • Inspect hive boxes, lids, bottom boards, and covers for damage.

  • Make sure hives are elevated and positioned to avoid standing water.

  • Check that equipment is secure and weather-resistant.

  • Evaluate ventilation and moisture management for your local climate.

  • Make any necessary repairs before temperatures become consistently cold.

Why it matters:
Healthy wintering conditions begin with a sound hive. Preventing water intrusion, excessive moisture, and equipment problems helps colonies conserve energy and remain protected as temperatures fall.

8. Keep Detailed Fall Records

September inspections can provide valuable information that will help guide winter management and future beekeeping decisions.

What to do:

  • Record colony strength and food stores.

  • Document Varroa mite levels and treatments.

  • Note queen performance and brood patterns.

  • Record which colonies required supplemental feeding or additional management.

  • Track any colonies that may need closer attention as fall progresses.

Why it matters:
Accurate records allow beekeepers to identify trends and make better management decisions. Knowing which colonies entered fall strong, weak, well-provisioned, or under pest pressure can also help when evaluating colony performance in the spring.

September Wrap-Up: Setting Colonies Up for Winter

September marks an important turning point in the beekeeping season. The focus is shifting away from maximizing honey production and toward protecting the health and resources colonies will need to survive winter.

By taking a proactive approach throughout September, beekeepers can help their colonies make a healthy transition into fall and enter winter with the strength and resources they need for a successful spring.