By the way, if your new seedling isn't exploding in size in a month, you might want to enhance your soil with a layer of rich compost mulch on top, or replant the tree into a richer soil. Sand will make it easy for small roots to spread, but is not retaining any nutrients to fertilize the top of the tree to grow. You might be okay, but keep an eye on it so it continues at a steady pace.

Seed trees are often designed to grow underneath taller trees, and want the richness of lots of compost to develop a competitive root system. The first year, they don't need to be fried in full sunlight either, and will benefit from the shade of taller trees part of the day.