From Brown bee
Once the main nectar flow begins, the bees need enough space for storing honey. The beekeeper should closely follow the space situation in the hive and supply extra hive bodies when the space begins to be limited.
- In Finland, four new wax foundation frames are usually included in every newly added box until July. After July, when the main nectar flow is over, the bees usually do not build new cells/combs. No queen excluder is used in Finland, because the worker bees don't like to go through it. The first expansion is usually done carefully by waiting for the colony to fully fill the existing space (“delayed expanding”). The rest of the expansions are done slightly earlier, so that the bees don't feel too cramped.