September Beekeeping Checklist 2026: Winter Prep Starts Now

Why September Decides Whether Your Hive Sees Spring

The bees your colony raises this month are not like the ones flying today. Winter bees — fat-bodied, long-lived, raised on the last good pollen of the year — are the ones that have to carry the cluster from November to March. They are being reared right now, and three deadlines decide what shape they arrive in:

Everything below hangs off those three dates. This is the September checklist in the order that matters, not alphabetical order.

First: Verify Your Varroa Treatment Actually Worked

If you treated in August, the single most important September task is a 10–14 day post-treatment mite wash. Three of this fall's most-read treatment guides now say the same thing we have been logging in the app all season: do not assume the product worked — verify it.

• Wash 300 bees (half a cup) from a brood frame, same method you used pre-treatment.
• An effective treatment drops the count by ~90%. A count that has not collapsed is resistance or a failed application announcing itself.
• Sugar-roll counts read low — multiply by ~1.5 to approximate the alcohol-wash number.
• If verification fails, rotate to a different chemical class and re-treat now. The amitraz resistance rotation plan covers which class follows which, and the varroa tracker charts your pre- and post-treatment washes side by side so the efficacy gap is visible in one glance.

Missed the mid-August window entirely? Treat now anyway — September is the last reliable chance to protect winter bees. The summer OA timing guide explains the window that just closed and what to use instead while brood is still present.

Fall Feeding: 2:1 Syrup, by Weight, Starting Now

September feeding is about stores, not stimulation — which is why the ratio flips from spring's 1:1 to 2:1 sugar to water, measured by weight, not volume. Two pounds of sugar to one pound of water gives the bees a thick syrup they can cure quickly with less fanning, in a month when cool nights make curing slow.

• Feed in bulk: a hive-top feeder taking a gallon or more beats an entrance feeder that invites robbing.
• Feed inside the hive, in the evening, and reduce entrances — robbing season is in full swing.
• Stop when daytime temperatures sit below ~50°F: cold bees stop taking syrup, and what they do take they cannot dry.

Work out exactly how much sugar your deficit needs with the sugar syrup calculator before you buy.

How Heavy Is Heavy Enough? Checking Winter Stores

Target stored honey by climate: roughly 40–60 lb in mild-winter regions, 60–90 lb in the cold North. In September you check this by weight, not by pulling every frame:

• Heft the back of the hive — if you can lift it easily with one hand, it is light.

• Better: a luggage scale under the back of the bottom board, doubled, gets you close enough to track week over week.
• Compare your number against your climate target with the winter feed calculator — it converts the deficit straight into pounds of sugar to feed while the syrup window is still open.

A hive sitting on a scale (or logged weekly in your records) turns "probably fine" into a number you can act on before it becomes a February emergency.

The Queenright Check and the Winter-Bee Brood Pattern

One more inspection while the weather allows. You are looking for two things:

• A laying queen. Eggs or young larvae present. September is the last practical month to fix queenlessness — after this, a queenless colony's only good outcome is being combined with a queenright one.
• A tight fall brood pattern. Smaller than July's, and that is normal — but it should be solid, not shot through with empty cells. This brood is your winter workforce; a spotty pattern plus a high mite count is the classic sign of a colony that will not make it unaided.

Combine Weak Colonies — a Strong Single Beats Two Dead Doubles

The hardest September decision is admitting a colony will not make winter alone. Low population, light stores, failed verification wash, no queen — any two of those and the kind move is a newspaper combine:

• Remove the poorer queen.
• Lay one sheet of newspaper over the strong colony's top box; cut a few small slits.
• Set the weak colony's brood box above it and close up.
• The bees chew through over a few days and merge without fighting; consolidate boxes once merged.

Do it while the weather is still warm enough for the colonies to reorganize. Two weak hives in November are two dead hives in February.

Entrances, Mouse Guards, and Robbing Season

The physical prep is quick and worth doing the same afternoon:

• Entrance reducers in — smaller entrances are defensible entrances during the fall robbing surge.
• Mouse guards on before the first cold nights send mice looking for a warm, honey-stocked cavity.
• Tilt the hive slightly forward so autumn rain runs out, not in.
• Ventilation and moisture control get their own treatment in our winter feeding and survival guide — condensation, not cold, is what kills clustered bees.

The One-Page Version

Verify the treatment (wash at day 10–14, ×1.5 if sugar roll). Feed 2:1 by weight until ~50°F. Get stores to 40–90 lb by climate. Confirm a laying queen and a solid pattern. Combine what cannot stand alone. Reduce, guard, tilt. Log each check per hive as you close the lid — the colonies that see spring are the ones whose September numbers you actually wrote down.

Frequently Asked Questions

When should I stop feeding syrup in the fall?

Stop feeding 2:1 syrup once daytime temperatures reliably drop below about 50°F (10°C), because the cluster stops taking it and cannot evaporate the extra moisture. In most northern regions that means syrup feeding effectively ends in October; after that, switch to fondant or a candy board placed directly above the cluster if a colony is still light.

How do I know if my varroa treatment worked?

Run a mite wash 10 to 14 days after your treatment ends and compare it against the wash you took before treating. An effective treatment drops the count by roughly 90 percent. If the count has not collapsed, do not assume the product worked — rotate to a different chemical class and re-treat while there is still time before winter bees emerge. Note that sugar-roll counts read low; multiply a sugar-roll result by about 1.5 to approximate the true level.

How much honey does a hive need to survive winter?

Plan for roughly 40 to 60 pounds of stored honey in mild climates and 60 to 90 pounds in cold northern winters. In September the practical check is weight: heft the back of the hive or put it on a scale, compare against your target, and make up any deficit with 2:1 syrup while the bees can still take and cure it.

Is it too late to treat for mites in September?

No — September is the last reliable window to protect winter bees, and treating now is far better than not treating at all. The bees emerging in late September and October are the ones that must live until spring, so a colony above threshold should be treated immediately with a product suited to current temperatures. What is too late is waiting until November and hoping.

Can I combine two weak hives in the fall?

Yes, and September is the right month to do it. A single strong colony winters far better than two weak ones, which usually both die. Remove the poorer queen, stack the weaker brood box above the stronger colony over a sheet of newspaper with a few small slits, and let the bees chew through and merge over several days. Combine before cold weather locks the clusters in place.