🌸 Tolumnia 'BlackBall' × 'BlackBull' Care Sheet (Closed Terrarium Setup)
A striking miniature hybrid with deep, velvety blooms—ideal for high-light, airy terrarium environments.
🔍 Quick Info
Type: Miniature epiphytic orchid (Oncidiinae alliance)
Size: 5–12 cm tall
Flowers: Dark red to near-black with vivid contrast patterns; starry and bold; blooms on slender upright spikes
Bloom Season: Spring through autumn (can rebloom multiple times per year)
Growth Habit: Fan-shaped pseudobulbs with wiry roots
🌡️ Temperature & Humidity
Day Temp: 22–30°C
Night Temp: 16–20°C
Humidity: 60–80%
✅ Can thrive in closed terrariums if airflow is provided
⚠️ Tolumnias must dry between waterings—they rot easily in stale, moist air
💡 Light
Requirement: Bright, filtered to high indirect light
Natural Light: East-facing or bright north-facing window
Artificial Light: LED grow lights (12–14 hours/day)
✅ Needs higher light than most terrarium orchids
❌ Avoid direct sun, but prioritize brightness
💧 Watering
Method: Soak roots thoroughly, then allow to fully dry
Frequency: 2–3× per week in active growth, less in cooler months
Water Type: RO, rainwater, or distilled only
✅ Mimic a wet–dry cycle
❌ Never let roots stay wet—root rot develops quickly in moist terrarium moss
🌱 Potting & Mounting
Best Setup: Mounted on cork or driftwood with little or no moss
Alternative: Mini basket or mesh pot with coarse bark or LECA
✅ Avoid sphagnum moss or closed pots—needs open airflow
❌ Never pot in compact medium
🌬️ Air Circulation
Vital to success in terrariums
Use a USB fan or open the lid regularly (2–3× per week)
Prevents bacterial issues and supports healthy root drying
🌿 Feeding
Fertilizer: Balanced orchid feed at 1/4 strength
Frequency: Weekly during growth
Flush: Once a month with plain water to remove salt buildup
⚠️ Terrarium Tips
Keep plants close to the light source
Never crowd Tolumnias—leaves need room to breathe
Trim dead roots or old fans to encourage growth
Monitor root colour—silvery when dry, green when freshly watered
✅ Ideal For
Bright, well-ventilated terrariums with high humidity and open structure
Experienced growers who enjoy mounted or mini orchids
Orchid lovers seeking dark-flowering miniatures with dramatic appearance