Lobelia cardinalis ‘Mini’ Care Sheet
(Terrarium & Aquarium Guide)
Overview
Lobelia cardinalis ‘Mini’ is a dwarf variant of the classic Cardinal Plant. It maintains the same lush green-to-red hues but grows more compact, making it ideal for nano aquariums, foreground planting, and smaller terrarium landscapes. Unlike the standard form, it rarely exceeds 5–10 cm in height under submerged conditions.
1. Care in a Terrarium
Environment & Placement
Type: Marginal / bog plant; best used in humid terrariums or paludariums.
Light: Bright, indirect light. Under intense grow lights, its colors deepen (hints of reddish tones).
Temperature: 18°C – 28°C. Avoid drops below 12°C.
Humidity: 70–90% (perfect for closed terrariums).
Substrate: Moist, nutrient-rich soil or a mix of sphagnum moss, sand, and fine organics.
Watering: Keep consistently moist but avoid stagnant water pools unless it’s near a water feature.
Growth & Maintenance
Growth Habit: Very compact clumps (1/3rd the size of regular Lobelia cardinalis). Ideal for foreground “borders” in terrarium scapes.
Pruning: Pinch tips to maintain compactness and encourage lateral shoots.
Fertilization: Every 4–6 weeks with diluted liquid fertilizer (¼ strength).
2. Care in an Aquarium
Planting & Placement
Light: Medium to high lighting (redder tones under intense light).
CO₂: Not essential, but CO₂ greatly enhances compactness and color intensity.
Substrate: Prefers nutrient-rich substrates or root tabs.
Temperature: 20°C – 28°C.
pH: 6.0 – 7.5.
Growth Characteristics
Form: Naturally stays under 5–10 cm high, making it an excellent foreground plant. Leaves are smaller, rounder, and densely packed.
Pruning: Trim older stems and replant healthy tops for a carpet-like effect.
Fertilization: Weekly liquid fertilizers + iron supplements for vibrant color.
3. Common Problems
Fading Color: Not enough light or iron deficiency.
Melting Transition: Normal when moving from emersed to submerged growth; new submerged leaves will appear.
Slow Growth: Caused by insufficient nutrients or low light.
Quick Tips
Ideal for nano tanks and compact terrarium layouts.
Best planted in groups of 5–10 stems for a dense look.
Trim often—untrimmed stems tend to elongate and lose the tight "mini" look.