Okay, I couldn't resist...I ordered another 100 seeds from Treeseeds.com.
Yesterday I first soaked the seeds in 1C of warm water with 2T of 3% hydrogen peroxide. I then rinsed them off and let them sit in water overnight. Today, I drained them and popped them into the fridge in little bags with a bit of damp sphagnum moss. (I basically follow Jonas' instructions)
Interestingly about 90% of each batch of seeds was viable according to the float test: after 24 hours 36 out of 40 from MySeeds.co and 91/100 from TreeSeeds.com were at the bottom.
Some hypnotic video of neutrally buoyant seeds scarifying:
After 10 days under lights, 70F bottom heat the indoor flat has started germinating. The outdoor one doesn't show any sprouts yet; despite the 70 degree days last week the cooler nights (40s) are probably slowing it down.
It has now been two weeks since taking the cuttings. I placed some in part sun, some under 50% shade cloth, and some in domes under lights. After two weeks the unprotected cuttings have all dried up. 100% of the cuttings in the domes are alive. Surprising me, the shade cloth cuttings are also all alive at this point.
Here is a comparison between cuttings vs. uncut seedlings. The uncut seedlings are a bit ahead -- they have already extended quite a bit while the cuttings are just starting to push. This is probably in large part because the uncut seedlings have been in full sun since February whereas the cuttings spent time under lights then under 50% shade cloth. I've moved some of the cuttings into full sun and it will be interesting to see if they catch up by the end of summer.
I've been periodically spritzing with hydrogen peroxide, other than that I've just been watering and fertilizing. A few weak uncut seedlings have been lost. So far, 100% of the cuttings are still alive.
A comparison of some of my seedlings at the end of summer. Going left to right:
2-year seedling cutting for comparison
A handful of seedlings I never turned into cuttings
4" pots
3" pots
6" colanders
There is some variation but the larger pots seemed to perform the best. Overall, the colanders were the weakest. Might be better to start in 4-5" pots and then shift to colanders?
At this point I've lost a grand total of 1 seedling cutting, and that was one I stuck in peat/perlite because I ran out of prepared pots. Interestingly enough 3 others are still going strong in that mix, I would have thought it far too wet.
A comparison of the foliage. The uncut seedlings have more mature foliage and are denser. A lot of the seedlings have low buds, some have multiple sets.
The "weak" seedlings sometimes seem to have potential to be good trees. They are small now, but they often have tighter internodes. I made some of the trees like the ones on the right into exposed root pines in my last batch and I think they could be interesting in a few years.
Interestingly enough my results from the previous year in USDA zone 6b were pretty similar. n=2 makes it hard to understand the factors that influenced the results, but my best guesses are (in rough order of importance):
Start early, under lights + bottom heat
Keep cuttings under domes until they grow roots
Full sun, but not 12 hours a day. They need some bright shade early on.
LOTS of water* (3x per day) and fertilizer.
Spray antifungals once a week (usually just hydrogen peroxide 2T/quart)
Maybe the mycorrhizae in the Pro Mix BX help?
*I think JBP actually like to be wet. The three uncut seedlings above were in sopping wet soil and clearly were growing like crazy. They want high oxygenation though which requires a large aggregate in your substrate.
It's been about 5 weeks since I repotted some of the pines in 9" colanders. They are just now starting to grow roots through the bottom of the colanders.
Awesome! I always had a hunch that seedling cuttings would do better in a propogator.I have some JBP under lights now just getting ready to cast the seed shell.I was going to make seedling cuttings with my propogator and a t5 ,but have decided to just let grow.I am going to pot early on into 2 3/4” Rootpouch pots.They have aeration all around,which I like and hopefully get good branching roots that will fascilitate first pruning nicely.
I have a full spectrum LED Quantum Board to keep them happy till Spring!......hopefully....I started big time early