I have done vermicomposting in the pot I plan to grow my tree in and am now planning to grow my maple for the 5th time in nutrient rich soil. My 4th attempt died last year of nutrient deficiency(growth stunted(1 inch, than 1/2 inch, than 1/4 inch, than 0(daily growth rate)), yellowing of leaves near the petiole but not at the tip, leaves still baby leaves, no overwatering(only gave it 1 deep watering close to the seed when I planted it, the rest of the water came from morning rain showers), leaves falling off, death, in sequence) and besides, I do have worms in there that use the nutrients not only to add to the soil but to nourish themselves and their babies.

There is only 1 thing that is concerning me. I have stratified the seed. I have made sure the soil is nutrient rich. I have made sure that my tree will get enough sunlight once it gets into the bigger pot with the vermicompost(if I decide to in fact transplant it). I know that as long as the soil is moist, my tree will be fine and thus I only need to water when the soil is dry(which is mostly in the summer). But 1 thing, of all the things that could concern a gardener, concerns me, and that is cold snaps.

Winter has just started about a week ago so it won't be for a few more months but I am worried about cold snaps. And nightly cold weather worries me too. Here is the thing. I know that maples are cold hardy and can survive into the negatives and are also heat hardy and can survive into 100+. But that is when the trees have bark on them. A seedling can easily be cut off from its roots by cold weather. This is what I am worried will happen if I plant my seed outside in March is that my seed will sprout and then later on get cut off from the roots by a cold snap. And at that young age, the roots can't regenerate a tree. Yes, if a tree gets cut down naturally or by humans, the stump that is left can grow new trees. I saw that in action a few years ago when I saw 5 maple saplings come out of 1 tree stump. That is all thanks to an intact root system.

But if a sapling gets cut accidentally, it can't regenerate. And if a seedling gets cut off by cold weather, that is even worse, the new roots will rot away unlike an older tree where the roots stay intact.

So I am worried that if I plant my maple seed outside, the sprout will get cut off by cold weather at night and during cold snaps. But I want to make sure that my maple gets sunlight that it needs. So should I plant it inside in March and then transplant it later on in April or May when I know that it won't get into the 30s until months later?