Propagating Dwarf Baby Tears (HC Cuba)

How to propagate Hemianthus callitrichoides 'Cuba' by splitting the mat and replanting small clumps in a grid, with the high light and CO2 it needs to carpet.

Overview

Hemianthus callitrichoides 'Cuba' (HC), often called dwarf baby tears, is endemic to the West Indies and was first collected in 2003 from Las Pozas in Cuba. It carries the smallest leaves of any common aquarium plant and is used as a foreground or carpeting species. It is rated an advanced plant with high light and high CO2 demand, and it grows into a fine dense lawn when those conditions are met.

Because HC spreads horizontally rather than growing as tall stems, propagation is about multiplying and spreading the existing mat rather than taking single cuttings. Each planted portion sends out runners that branch and creep along the substrate, gradually knitting separate clumps into one carpet.

Propagation Method

HC is propagated by dividing the carpet into small portions and replanting them, supported by the runners each portion naturally produces. A 1·2·Grow! cup or an established patch holds many plantlets that can be split apart to cover a much larger area. Both the submersed mat and emersed-grown stock can be divided, though emersed growth needs time to convert under water.

Step-by-Step

1. Lift a section of established carpet or open a cup and gently tease the mat apart with tweezers.
2. Divide it into small clumps of a few stems each, keeping fine roots attached where possible.
3. Plant the clumps a few centimetres apart in a grid across the substrate so they can fill the gaps.
4. Push each clump just into the aquasoil so roots anchor but the crown is not buried.
5. Keep light and CO2 high from day one; the portions spread rapidly and the runners merge into a carpet.

Conditions for Healthy Growth

HC needs high light and a high CO2 level (Tropica cites roughly 15-25 mg/L) to carpet successfully. Provide a nutrient-rich aquasoil, good water circulation and regular fertiliser. Under these conditions it reaches about 3-5+ cm after two months and produces visible oxygen bubbles, a sign it is thriving.

Trimming & Maintenance

Trim the carpet regularly; otherwise the lower parts stop receiving light, which causes root death and patches detaching from the substrate. Frequent light trims also keep the lawn thin and even, and the clippings can themselves be replanted to extend the carpet.

Common Challenges

Emersed-grown portions take time to adapt to fully submersed growth, so expect a transitional period before the carpet thickens. Patience, stable CO2 and steady trimming are the keys to a lasting lawn.