80% of the action in a 2 box deep hive is going on in the upper deep. While I don't think that it hurts anything to look through the bottom one, I don't think that it will be long before you look at the top box and decide that it is too much trouble for what you might learn.
The times that I go through the bottom box are when I am requeening and she happens to be down there, or sometimes when I am making nucs.
I look in the spring when there are no bees down there to decide which frames to toss.
When you take off the top box (and maybe honey supers on top of that), you will find that the returning bees stack up and start overflowing the sides of your bottom box since they can't move on up.
The times that I go through the bottom box are when I am requeening and she happens to be down there, or sometimes when I am making nucs.
I look in the spring when there are no bees down there to decide which frames to toss.
When you take off the top box (and maybe honey supers on top of that), you will find that the returning bees stack up and start overflowing the sides of your bottom box since they can't move on up.
