[8/16/16 – See the updated and expanded version: How to grow Japanese black pine from seed]
I planted pine seeds again this year – black and red. The seeds came from Shikoku, Japan. It’s legal to import pine seeds – permits are available from the USDA – and the process is surprisingly simple. Once I got them home, I waited impatiently for late winter to begin preparing them for spring planting.
In past years, I soaked the pine seeds in water for one to three days and then planted the seeds that sank to the bottom of the glass. This year, at the advice of a friend, I scarified and stratified the seeds before planting (thanks “Juan”!). Instead of dropping the seeds into tap water, I poured near-boiling water over the seeds and let them cool and soak for 24 hours. The hot water scarifies the seeds by softening up their hard coating – a necessary step for germination. I then placed the seeds in plastic bags filled with moist white sphagnum moss. I placed these bags in the refrigerator where they were intended to sit for one to two weeks. By stratifying the seeds – placing them in a cold, moist environment that simulates natural spring conditions – I help the seeds break their dormancy so they can sprout.
One thing seemed to lead to another and I didn’t get around to actually planting the seeds for over a month. No matter – the seeds sprouted just fine.
Seedlings rising from the sand
To better gauge the effect of stratification, I planted a number of seeds directly after soaking them for 24 hours. In the photo below, you can see that the stratified seeds, on the left, have germinated much faster and with greater consistency than the un-stratified seeds to the right of the aluminium wire.
Stratified seeds :: un-stratified seeds
Continued warm weather is bringing more seeds into the light each day. It’s been a fun process to watch.
A seedling prepares to cast off its protective shell.
How are last year’s seeds doing? Pretty well. Most survived the seedling-cutting process and are now growing quickly. I’ve found that my pines take about two years to reach the height seedlings in Japan reach in their first year (see Bonsai Today #12 or #20 for comparison).
Two-year old seedlings
Not all, however, are as healthy as this. The most vigorous 2-4″ tall – the stragglers, somewhat less. You can see the range of heights below.
Two-year old seedlings
More vigorous seedlings
Less vigorous seedlings
For those who missed my posts about collecting and planting pine seeds, check out the following: