Most of our customers don't go out of their way to produce lots of honey, but some do, and as a beekeeper you should understand the nectar flows in your area, regardless. If you are supering your hive(s) in order to produce more clear honey or comb honey, the supers must be put on at the beginning of a strong nectar flow; not before it begins, not half-way through it, and obviously not after it has ended. Otherwise, the queen may wander up into your supers and lay eggs or the bees may just ignore them altogether (it takes lots of nectar to draw wax comb). It's also important to understand nectar flows so that you can recognize a dearth (a period when nectar is not available) because nectar dearths are times when your bees are vulnerable to robbing and/or starvation.
So, what is a nectar flow? Also called a honey flow, it's a period of time, usually a few to several weeks long, when an abundance of one or more nectar producing plants are in bloom. These are the times when your bees can produce lots of honey. So, how do you recognize a nectar flow? You have to find out what plants you're looking for. Asking other, more experienced beeks in your area is probably the best way. They can likely tell or even show you the main plants in your area that the bees work heavily each year, and hopefully give you some kind of timeline. Another way is to just simply open your eyes to the world around you. Almost any nectar producing plant within two miles of your bees is going to be getting worked by them. If you see a stand of wild flowers, a blooming tree or some unknown whatever, go look to see if bees are working it. Then, figure out what it is, whether or not it's abundant, and when it blooms. Nectar flows can consist of mostly just one species of plant producing significant nectar, or they can consist of several species producing at the same time. Here in Michigan, basswood trees, milkweed and, the biggest nectar producer by far, purple star thistle often bloom simultaneously. In addition to the tips I've given, we also sell a book called "Honey plants of North America" that will help you to identify and understand nectar producing plants in your area. It's an old publication (1926) and the illustrations are black and white, but it's still very helpful and interesting. Become a better beekeeper. Learn your nectar flows!