I have grown maples 4 times. Every time it was 1 or more seeds from a sugar maple and the seeds were viable(I could feel the seed inside).
First attempt:
Planting time: March 21st 2010
Number of seeds in pot: 4 of them equally spaced
Result: Nice growth during spring and summer but no bark formation
Hypothesis: Too much competition and root entanglement which broke the roots and thus none of the trees got enough nutrients to form bark
Second attempt:
Planting time: March 21st 2011
Number of seeds: 2
Result: 3 years of growth but none of them had leaf buds even in May of the fourth year. During the 3rd year 1 tree got wounded a lot in the bark. I would put tape on the wound, leave it there, and then gradually take it off until it was completely healed. I had a second pot which held the groundwater. This helped during dry spells to keep the soil moist for the trees. Some of these wounds were during mid-winter.
Hypothesis: Wounds leading to nutrient drainage + standing water
Third attempt:
Planting time: Don't know exactly but it was in May 2014
Number of seeds: 3
Result: Only 1 of them grew and during the fall the bark formed from top to bottom instead of from bottom to top which was unusual. The very bottom never grew bark(I don't think it was a very small creature eating the bark like my momma did, otherwise I would have seen an irregular pattern of bark and no bark and I did not see an irregular pattern).
Fourth attempt:
Planting time: May 20 2015
Number of seeds: 1
Result: This was my worst attempt. I planted it in shade and then watered a small radius. Then it rained for several days straight during the morning. I thought "Hmm, maybe it needs more sunlight to sprout." since it wasn't sprouting the day after I planted it like all my other attempts have. So during the sunny afternoon I put it in a sunny spot and 2 days later it sprouted. However things got worse from then on. It started growing and the leaves were growing too(I can tell my maples from weeds by the size of the baby leaves(maples have larger baby leaves than weeds) and always pull out weeds when I see them) It then started to yellow like it was overwatered but I did not water it for several days because of rain and moist soil. Then 1 baby leaf fell off. The second one fell off. I was hoping it would grow back because I knew that the roots of trees, both old and young can give rise to new trees if the older one dies but isn't uprooted. However it never grew back.
Hypothesis: Viral disease of the plant maybe? I don't know.
Now I never stratified these seeds, just found a viable seed in the spring and planted it right away. I think that the increased annual temperature helped during 2011-2013 since it got up to 104 degrees fahrenheit in Columbus, Ohio during 2012 and the older sugar maple that I got all these seeds from has survived that increase in temperature.
But from 2014 to this year it has been cooler summer and warmer fall and winter weather only staying in mid-winter. There have also been quite a few cold snaps during the spring these past few years which is why the planting time was delayed to May instead of March in the 2 most recent attempts. There have also been green leaves on trees during December(which I think is due to the warmer fall which feels like a longer summer to the deciduous trees).
Since the second attempt did very well without stratification for 3 years, I was hoping that I could get similar and in fact longer results by planting a single tree instead of 2.
So how could I improve the growth of my maples other than no standing water, growing them in sunny areas, reducing competition for nutrients, vermicomposting(that is making compost with the help of worms), and adding a worm or 2 to the pot I am growing the maples in to constantly fertilize the soil?
Would putting a heat mat underneath the pot during the spring and summer and taking it off during the fall and winter(since they seemed to do better when it was hotter spring and summer and colder fall) help at all when it gets to just low 80s during the summer and there are cold snaps in the spring? I would have to water it more often but that isn't a big deal.
Are there any plants that would help the maples grow? The ravine a few feet away from where I live has a lot of maples, elms, and oaks so maybe trying to grow elms and oaks along with maples will help?
There is also a fungus called Chicken of The Woods that grows there on old logs. It isn't poisonous and I have actually had it once and it was good(I usually don't like mushrooms so it was kind of a surprise when I tasted it). Moss and Ivy also grow a lot there, I am not sure how a parasitic plant like Ivy would help(Ivy most often grows on Oaks in the ravine and leaves maples alone) or how a fungus like Chicken of the Woods or moss would help but I will try just about anything to improve the growth of my maples.