The screen bottom board does two jobs: it manages airflow through the hive, and it gives you a low-disturbance window into colony health via natural Varroa mite fall. Because the high-density EPS walls and adiabatic seal handle thermal regulation so effectively, the screen contributes to ventilation without the heat loss that would occur in a wooden hive — you get the monitoring benefit without the insulation penalty.

For background on how the bottom board geometry fits into the engineered system, see Repairs and structural issues. For treatment protocols including oxalic sublimation, see Treatment compatibility.

The screen allows warm, moist air to move downward and out naturally while preventing cold air from drafting directly into the cluster. The result is moisture control without significant heat loss — a critical balance, since excessive moisture in winter is more damaging than cold.

By season:
- Spring/Summer — The screen manages moisture from brood rearing and nectar processing. Additional ventilation is typically unnecessary.
- Fall/Winter — Continues venting moisture without compromising cluster stability. Keep the Varroa tray removed (or lightly oiled and inserted for monitoring only) — continuous tray insertion restricts airflow.

The removable Varroa tray slides into the bottom board beneath the screen. Mites that are dislodged from bees fall through the screen onto the tray where they can be counted.

Note: Don't leave the tray inserted continuously during non-monitoring periods — it restricts airflow.

Fall threshold: In September–November, treat if counts reach 3–5/day — winter bees are being raised and mite loads at this stage disproportionately affect their quality.

Important: Use trend data, not isolated counts. One high reading during or after a treatment is expected. What matters is the direction: are counts rising, stable, or falling?

The Varroa tray, combined with monitoring, is what lets you decide whether and when to treat — Primal Bee supports both treatment-free (IPM-first) and treatment-based approaches, and that decision is yours.

Low mite counts despite suspected infestation: Verify tray alignment and sticky surface. Use a magnifying glass and a light-coloured tray for easier counting. Supplement with an alcohol wash for accuracy.

Signs of poor airflow (moisture, mould on comb, damp conditions): Clear any debris from the screen and entrances, and confirm the entrance reducers aren't overly restricted.

No. The tray should be inserted for monitoring periods only (24–48 hours). Continuous insertion restricts airflow beneath the screen. During winter, the tray can be left out entirely or only inserted briefly for monthly monitoring.

Weekly during the active season (spring through fall). A dirty tray makes accurate mite counting difficult and may trap debris that restricts airflow.

Yes — during oxalic acid sublimation (the recommended treatment method for Primal Bee), keep the tray inserted and lightly oiled to monitor mite fall as the treatment works. An increased mite drop during treatment is a positive sign of efficacy. Apply oxalic sublimation through the top feeder hole; Primal Bee retains vapor well. For full treatment guidance, see Treatment compatibility.

Zero mites is a good sign, but it doesn't guarantee zero mite infestation — natural mite fall fluctuates, and some mites remain in capped cells where they can't fall. Supplement periodic tray monitoring with alcohol washes (especially in late summer) for accurate colony-wide readings.