Tilia americana

Seeds Type

Orthodox, that is to say seeds with the capability to withstand desiccation and freezing temperatures (-20°C) and may therefore be conserved for years, if not decades.

For germination, you must...

1. allow THREE MONTHS for seed treatment;
2. subject them to a thermal scarification AND a cold stratification before sowing (follow the steps below in order).

Thermal Scarification : Soak the nutlets in hot tap water (around 60 ° C) and let the water cool normally for 24 hours.
Stratification (cold) : Place the nutlets in a bag (Ziploc Slider type) containing slightly premoistened peat moss. Seeds should be surrounded by the latter. Close the bag and place it in cool storage (between 1°C and 5°C) for approximately three months.
Seedlings : Remove the content from the bag and sow the seeds by broadcasting the mix on the growth medium. Bury lightly, less than five millimeters from the soil surface.
Comments : Germination can be very erratic. A small proportion of the seed lot may germinate after the stratification period of three months, but most of the seeds will only sprout two or three years after they have been sowed. Moreover, some seeds may take up to seven years before showing a sign of life.

⚠ Hard to germinate ⚠

Seeds from this species have a combinational dormancy. The pericarp is very hard and the seed coat is impervious to water, which represents a double physical dormancy. Embryo’s growth, inside the seed, is prevented by a factor that we didn’t identify yet, but could be its immaturity (morphological dormancy), its temperature sensibility (thermodormancy) or even its moisture sensibility (hygrodormancy). Embryo’s maturation progresses as the stratification takes place. Germination may occur several months - or even years - after sowing. It’s important to not throw seeds away if they didn’t germinate after the first attempt. Repeating all the germination process could be necessary.