Stratifying pine seeds

If you’re looking to plant seeds this spring, now may be a good time to do it. Considering how warm this winter has been in Northern California, January may have been a good time to get started, but either way it’s not too late to start now – weather permitting.

Many seeds benefit from scarification – treatments designed to pierce, damage or otherwise weaken the seed coating – and stratification – any means of providing artificial cool and moist conditions conducive to germination.

Pine seeds can be scarified by applying hot water. Stratification can be achieved by refrigerating seeds before planting (see Pine seed prep and Pine seedlings for an overview; treeshrubseeds.com provides details and specific instructions for different varieties).

Missing from my previous posts on the topic are photos. Here are a few shots of how I pack up the seeds after soaking them for 1-2 days.

Japanese black pine seeds – ready for the fridge

The moss is often sold as orchid moss or white sphagnum moss. I wet it and squeeze most of the water out before putting it in the bag. After a few minutes in the fridge, the bag fogs up.

Condensation in the bag

This year I’m planting red pine, black pine from Shikoku, and Mikawa black pine seeds.

Red and black pine seeds

After a full week in the fridge, I’ll plant them in a pot with bonsai soil and cover them with fine particles to keep them moist during germination. For details, see Planting pine seeds.