What to Expect in September in Northeast WI

Here is what to expect in and around the hive in September.

In the hive

The queen’s rate of egg laying slows and the brood area continues to contract. Little drone brood is laid. This is the end of a second, smaller swarm season. Nectar sources continue to diminish, although resin/propolis collection continues. Left untreated, the Varroa mite population usually peaks in August or September. The bees may be more defensive, protecting their hive and robbing other colonies.


  • This is the last month when a beekeeper can expect to perform thorough colony inspections. Roger Morse once wrote, “I often think of September as the month when one corrects errors made in August”.
  • The queen’s egg laying slows dramatically by the end of the month, so the brood pattern may be difficult to accurately evaluate.
  • You should have been keeping records the entire active season, but it is especially important now as your hive is readied for winter. Take note of the number of the bees/size of the cluster, the amount (weight) and position of honey stores they have, etc., so that if the colony fails, you can make a more accurate deadout diagnosis in the spring.
  • Bees may rob hives left open during a long inspection. Be thorough but efficient.


  • A full-sized colony should have at least 70-90 pounds of honey to eat by the beginning of October, or more than one full deep. (Nucs of course need less.) Estimate the eight by slightly tipping and hefting the hive, or use a hive scale. If you extract honey, leave enough for the bees or feed them heavy sugar syrup to make up for the difference.
  • If you feed the bees sugar syrup, it should be a 2:1 ratio, thicker than the spring feed; the bees can evaporate the excess moisture from the hive faster from this thicker syrup. The bees will need at least two double-sided frames of pollen/bee bread by late winter/early spring. September is the last month it is recommended to feed pollen or pollen substitute for the remainder of autumn, as bees use the reduction in pollen flow as a cue to begin rearing winter bees.
  • If the weather is dry and there is no water source near the hive, consider providing one.
  • If you plan to raise rear queens next year, begin to prepare cell finishers this fall: feed it lavishly now (carbohydrates and protein).

Pests, parasites, and diseases

  • Monitor for Varroa mites. At this point in the year, if you find three or more mites (per 100 bees) from a sugar shake, ether roll, or alcohol wash, you will want to treat. If you have extracted your honey harvest, this is a good time to use treatments that cannot be used when supers are present.
  • Remove drone comb foundation for the remainder of the year.
  • Monitor for Nosema. It is present all year round, but regular monitoring will help you understand your normal levels and when/if they peak, particularly if you are seeking to understand why a colony is struggling.

Population management

  • Consider combining weak colonies with strong ones or culling them: if a colony can accurately be judged as doomed, it will probably be a waste of resources to try to overwinter it individually.
  • If you are considering re-queening, this is a good month to do it. An overwintered young queen should start laying a good pattern in the spring.
  • Do not interrupt the brood pattern in September as it may disrupt the production of winter bees.


  • Removing bees from honey supers may require a fume board, bee brush, bee escape, or other tools; they each have advantages and disadvantages for different beekeepers and in different environmental conditions.

Hive products and services

If you remove fall honey, it should be extracted immediately afterward to prevent a small hive beetle infestation. Fall honeys usually granulate more quickly than spring honeys and may need to be warmed a bit to flow through filters or other equipment.

Yard maintenance

  • Mow the yard as necessary.

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