Pollen and Nectar Relation

[tbonekel]

I know that this is probably very specific toward each individual plant, but has there been a study as to the length of time from pollen production to nectar production for general plants? I ask because today was a particularly busy day for pollen harvesting. Do any of you have a basic standard as to how long it takes the bees to start bringing in nectar after pollen? I know that is probably very difficult to answer. Down here we have those fruitless bradford pear trees that are really beautiful right now. I don't have one, but my neighbor does and my bees were all over it today. Also, we have dandelions pretty much year around, but I don't know if they always have nectar available or just certain times of the year.

[Bakersdozen]

tbone- that is quite a question and I don't think it has a definitive answer.  The length of time from pollen to producing nectar would vary from plant species to plant species.  Other variables would include rainfall amounts, rain at the wrong time, temperature, insect damage, soil conditions, amount of sunlight to name a few.  Different plants have different requirements for maximum nectar production.
Some plants only produce nectar during certain times of the day.   
Pollen being brought in is a good sign of a queen that is laying.  They will need all that pollen for food.

[apisbees]

Some plants produce Nector to attract the pollinators others do not. The plants developed with its native pollinator in a way to be attractive to its pollinator. Bees are not the native pollinator to most of the crops grown today. It is because of the bees need for an abundance of pollen and nector to raise brood and to service the winter dearth that makes then an fees hens pollinator for all the crops they are used to pollinate. This being said as tbonekel said each plant and variety of plant produces different amounts of pollen and nector, even producing only one. Ther are books on plants and their attractiveness to bees and it is a case of cross referencing the plants that will grow in your region against the listed plants. Another good source is fellow old time beekeepers and their experiences.
In choosing plants it is also important to keep in mind the time of year the plants will bloom. A field full of bloom may provide a surplus of honey for the beekeeper for 2 to 3 weeks but what is available for the bees the rest of the year. It is important to provide a sustainable food supply for the bees, this can only be done by feeding of selecting plants to fill in the gaps when bee plants are not available to the bees.

[Slowmodem]

One thing I found interesting is that bees will work different plants at different times of day.  I don't know if it has to do with dew or what, but I believe there is more nectar at different times of day, depending on the plant.

[apisbees]

To add to what slowmodem said the temperature can effect when the plant will start to produce nectar also.