How to germinate White Pine (Pinus Parviflora) seeds

I bought a large JWP tree (Pinus Parviflora Glauca) and there were a bunch of opened cones in there with some ripe seeds. I would like to plant them using a tested method since I only have a few seeds.

Looking on the internet I found these instructions but I’m unsure if this will work (assuming the seeds are good). Has anyone here had any success growing white pines from seeds?

From SFGate -

  1. Float the seeds in a bucket of water overnight to determine which are viable. Discard any seeds that float since their embryo is likely dead. Drain off the water and remove the seeds that sank.

  2. Place the seeds in a freezer bag filled with lightly moistened perlite. Store them in the refrigerator for two to three months. Remoisten the perlite whenever it feels mostly dry.

  3. After the cold stratification period has ended, fill 5-inch square pots with a mixture of half sharp sand and half milled sphagnum moss. Saturate the mixture with water and let it drain off.

  4. Sow one white pine seed in each container. Poke a 3/4-inch-deep hole in the growing mixture. Set the seed inside horizontally and cover it with loose sphagnum moss. Spread a 1/8-inch-thick layer of sand over the sphagnum.

  5. Place the growing containers outdoors in a greenhouse or inside a cold frame with insulated glass. Warm the pots with a propagation mat set to 70 F at night and 85 F during the day.

  6. Probe the growing mixture every day to test the moisture level. Add water whenever it feels barely moist in the top inch. Water slowly until a small amount of moisture trickles from the bottom of the pot.

  7. Watch for germination in two to six weeks. Leave the propagation mat in place but only turn it on at night. Set the temperature to 65 F. Continue to water whenever the growing mixture feels dry in the top inch.

After step #1 I like to plant them in a tray or pot that is 2-3 inches (5 - 8 cm) deep on 1.5 inch (4 cm) centers. Cover with wire mesh or screen to keep the critters out and place outside for the winter where they will get some moisture. Less chance of fungus infections, closer to the process they see in the wild, and far easier than 1 seed per pot. I typically transplant into individual pots after two years.

I have just started to use a fairly compact layer of mixed grade pumice in the bottom of the tray that is about 1 inch (2.5 cm) thick and tamped down. Then a layer of pumice mixed with screened potting soil (Miracle Grow through a 1/4 inch (6 mm) screen) about 3/4 inch (2 cm) thick that is not tamped as tightly. The seed goes into divots pressed into the soil and are then covered with a mix of pumice fines and potting soil. This is based upon something I saw in one of the magazines and the idea is that the interface between the two layers will force the roots to spread. I will find out how well it works in a couple of years.