Using a ten frame traditional hive, one brood box and one super at the moment. We are in the middle of spring and there is a great flow on at the moment. I inspected a few days back and supers are filling up with nectar (about half full), i.e. most cells have nectar in them but hardly any capped.
I am wondering when to add a second super as I think I cannot wait until they cap the existing frames because there is so much nectar coming in.
Also, would you add the super above or below the existing super?
Here is the way I would handle it. Place the extra super on the top with wired foundation frames and the bees should continue to dry the honey then cap it. Then they will also be drawing out comb in the top super and as too much nectar is brought in the bees will start storing in the drawn out frames.
You should be expecting a constant and good honey flow from now on till at least mid Autumn down there.
Regards
My answer is the same as for adding any box (brood or super) any time. I like to keep it simple. When all of the comb is fully drawn and 80% of the comb is full (not necessarily capped), plus there are plenty of bees on each frame, you can add another box. It sounds like this is now (or perhaps next week) for you.
Always above for new supers. I only add new brood boxes below the existing box if it is a new hive (which needs 2 brood boxes), and I am going to be away for a few weeks during the nectar flow.