Plant growing system

1. A plant growing system, comprising:

a first light source for irradiating red light to a plant;

a second light source for irradiating far-red light to the plant;

a control part that controls irradiating operations of the first light source and the second light source; and

a time setting part that sets a time zone in which the control part operates the first light source and the second light source,

wherein the time setting part is designed such that the first light source starts red light irradiation before sunset; and the second light source starts far-red light irradiation after the red light irradiation.

2. The plant growing system as set forth in claim 1 ,

wherein the time setting part is designed such that the second light source starts the far-red light irradiation after the red light irradiation of the first light source is completed.

3. The plant growing system as set forth in claim 1 ,

wherein the first light source has a peak wavelength in a range of 610 to 680 nm and the second light source has a peak wavelength in a range of 685 to 780 nm.

4. The plant growing system as set forth in claim 1 ,

wherein the first light source and the second light source are realized by controlling a wavelength of light emitted from a single light source.

5. The plant growing system as set forth in claim 1 ,

wherein the second light source emits the far-red light with irradiance of 0.02 W/m 2 or more and integral irradiance per day of 0.2 kJ/m 2 or more.

6. The plant growing system as set forth in claim 1 ,

wherein the time setting part is designed such that the first light source emits the red light until a first time zone near sunset; and the second light source emits the far-red light until a second time zone near sunset.

7. The plant growing system as set forth in claim 1 ,

wherein each of the first light source and the second light source includes a filter through which sunlight passes; and the second light source emits far-red light with irradiance of 0.5 W/m 2 or more and integral irradiance per day of 1 kJ/m 2 or more.

8. The plant growing system as set forth in claim 1 ,

wherein the time setting part is designed such that the second light source emits the far-red light from near the end of red light irradiation of the first light source until near sunset.

9. The plant growing system as set forth in claim 7 ,

wherein the filter of the first light source is a red filter through which the red light with a wavelength in a range of 610 to 680 nm is passed and the filter of the second light source is a far-red filter through which the far-red light with a wavelength in a range of 685 to 780 nm is passed.