Light source for plant cultivation

1. A plant cultivation light source, comprising:

a plurality of light sources configured to be turned on or turned off depending on a selected plant and a growth stage of the selected plant; and

a controller operable to turn on the light sources during a light period such that the light sources are operable to emit a light having a spectrum with a plurality of peaks to the selected plant;

the light period comprising a first period and a second period and the first period preceding or following the second period;

wherein the controller is operable to adjust the spectrum of the light to:

provide, in the first period, a first pattern having peaks of the light that appear at one or more wavelengths;

provide, in the second period, a second pattern having peaks of the light that appear at the wavelengths being similar or identical to the wavelengths of the first pattern;

further provide, in the second period, at least one peak of the light that appears at a wavelength equal to or smaller than about 300 nm; and

alternate the first period and the second period during the light period.

2. The plant cultivation light source of claim 1 , wherein the light sources emit the light having the first pattern in the first period that enables photosynthesis of the selected plant.

3. The plant cultivation light source of claim 1 , wherein the controller further controls the light sources to continuously irradiate the light in the second period.

4. The plant cultivation light source of claim 1 , wherein the controller further controls the light sources to irradiate the light in the second period in a flickering manner.

5. The plant cultivation light source of claim 1 , wherein the first period is longer than the second period.

6. The plant cultivation light source of claim 1 , wherein the controller further controls the light sources to continuously irradiate the light in the first period.

7. A plant cultivation light source, comprising:

a plurality of light sources configured to be turned on or turned off depending on a selected plant and a growth stage of the selected plant, the light sources comprising a first light source and a second light source; and

a controller operable to turn on the light sources during a light period such that the light sources are operable to emit a light having a spectrum with a plurality of peaks to the selected plant;

the light period comprising a first period and a second period and the first period preceding or following the second period;

wherein the controller is operable to adjust the spectrum of the light to:

provide with the first light source, in the first period, a first pattern having peaks of the light that appear at one or more wavelengths to be used in photosynthesis of the selected plant;

provide with both the first light source and the second light source, in the second period, a second pattern having peaks of the light that appear at the wavelengths being similar or identical to the wavelengths of the first pattern; and

further provide, in the second period, at least one peak of the light that appears at a wavelength equal to or smaller than about 320 nm;

wherein during the light period, the second period does not exceed the first period.

8. The plant cultivation light source of claim 7 , wherein the controller is further operable to alternate the first period and the second period during the light period.

9. The plant cultivation light source of claim 7 , wherein the controller further controls the light sources to continuously irradiate the light in the second period.

10. The plant cultivation light source of claim 7 , wherein the controller further controls the light sources to irradiate the light in the second period in a flickering manner.

11. The plant cultivation light source of claim 7 , wherein the controller further controls the light sources to continuously irradiate the light in the first period.

12. The plant cultivation light source of claim 9 , wherein the controller further controls the light sources to continuously irradiate UVB in the second period.

13. A method for operating a light source for plant cultivation, comprising:

turning on or off a plurality of light sources depending on a selected plant and a growth stage of the selected plant during a light period, the plurality of light sources comprising a first light source and a second light source;

wherein the light period comprises a first period and a second period and the first period preceding or following the second period;

controlling, with a controller, the light sources during the light period to emit a light having a spectrum with a plurality of peaks to the selected plant;

adjusting, with the controller, the spectrum of the light to:

provide, in the first period, a first pattern having peaks of the light that appear at one or more wavelengths;

provide, in the second period, a second pattern having peaks of the light that appear at the wavelengths being similar or identical to the wavelengths of the first pattern;

further provide, in the second period, at least one peak of the light that appears at a wavelength equal to or smaller than about 300 nm; and

alternate the first period and the second period during the light period.

14. The method of claim 13 , further comprising continuously irradiating the light in the second period.

15. The method of claim 13 , further comprising irradiating the light in the second period in a flickering manner.

16. The method of claim 13 , further comprising continuously irradiating the light in the first period.

17. The method of claim 13 , wherein adjusting the spectrum of the light further comprises:

providing with the first light source, in the first period, the first pattern having the peaks of the light; and

providing with both the first light source and the second light source, in the second period, the second pattern and the at least one peak of the light.