How to germinate Gmelina arborea

Gmelina arborea is a fast-growing deciduous timber tree native to South and Southeast Asia, widely planted for light construction, pulp, fuel, and as a shade tree in agroforestry systems. Seeds have physical dormancy from hard seed coat but respond well to pre-treatment

Before sowing

Scarification

quimica Chemical scarification with concentrated H2SO4 for 10 minutes very effective; increased water uptake to 68% vs 15% in unscarified seeds

Soak

24 h Soak seeds in cold water for 24 hours before planting to soften seed coat; alternatively 48 hours in warm water for quick germination

Seeds have physical dormancy due to hard seed coat. Soaking nuts in water at 25°C for 17 hours followed by drying at 45°C for 7 hours yields 88% germination. GA3 at 200 ppm achieves 98.88% germination

Sowing

Substrate

Sand and loam mixture or well-draining soil. Optimal mix: 2 parts soil and 1 part sand. Avoid pure sawdust

Depth

1cm

Temperature

25°C

Moisture

media

Container

Germination beds, seed boxes, nursery trays, poly-potted containers

Day/night swing

9 cycles of alternating temperature at 30°C for 16 hours and 45°C for 8 hours promotes best germination results

What to expect

Step 1

Pre-treat the seed

Step 2

Sow at 1cm · 25°C

Day 7–50

Seedlings emerge (~65%)

Tips

Seedling growth depends heavily on light availability. Requires full sunlight for optimal establishment. Seeds require complete removal of residual pulp after drying. Stored seeds (dried to 8% moisture at 3°C) germinate better than fresh seeds. Maintain warm and humid environment around 25°C during germination

Sources: Winrock International Gmelina arborea publication; FAO Forest Research Centre Sepilok studies; ResearchGate pre-sowing treatment research; Tropical.theferns.info; Plant World Seeds; Multiple horticultural guides

Fresh seeds to sow

Gmelina arborea

Before sowing

Sowing

What to expect

Tips

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