Yes, the light cycle is about one month. 29.53 Earth days, to be precise. (the difference is because the moon is also orbiting the sun, and after a month the sun's direction is 1/12th way further around the celestial background)

Yes, these days consist of one unbroken sunlight period, followed by one unbroken darkness period. The exact ratio of the two would depend on local geography, you lattitude on the globe, etc, same as day vs. night length on Earth varies by location and season.

And yes, it would present immense problems for greenhouse growing of plants.

Yes, the light cycle is about one month. 
29.53 Earth days, to be precise. (the difference with your figure is because the moon is also orbiting the sun along with the Earth, and after a month the sun's direction is 1/12th way further around the celestial background)

Yes, these days consist of one unbroken sunlight period, followed by one unbroken darkness period. The exact ratio of the two would depend on local geography, your latitude on the globe, etc, same as day vs. night length on Earth varies by location and season.

And yes, it would present immense problems for greenhouse growing of plants.

Another of the problems is the radiation environment on the Moon, both in terms of ionizing radiation and unfiltered solar light.

Yet another is the thermal environment. The moon's surface temperature varies from as high as about 100C down to as low as -180C. Obviously this is very bad for any life, including your greenhouse plants.

A realistic greenhouse on the Moon is an underground structure, shielded from the extremes of temperature, radiation and the vagaries of sunlight.
Illuminated purely by artificial lighting in the form of grow lamps.

The power source for the grow lights could be from solar panels and storage batteries, but is more likely to be nuclear.