Curtains & Supplemental Lighting in Greenhouses

1. Curtains & Supplemental Lighting in Greenhouses

2. Terms • photoperiod • photoperiodism • energy curtains • shade curtains • short-day curtains • supplemental lighting • fluorescent lighting • high intensity discharge lighting system • incandescent lighting

3. Why do we use curtains and supplemental lighting? To control the amount of light in the greenhouse Photoperiod- duration of time that light shines on a plant each day.

4. Photoperiod • The lengths of light and dark periods have a definite effect on the growth of plants. • The longer the light period, the more time there is for photosynthesis. (more growth) • Plants make their greatest amount of growth with a long day and a short night. • Photoperiodism- plants response to day length

5. Three Classes of Plants: • Short-day plants • Flower when the day length is shorter than a critical number of hours. • Long-day plants • Flower only if the day length is longer that a critical number of hours. • Day-neutral plants • Day length does not affect flowering directly.

6. Curtains Energy curtains Shade curtains Short-day curtains

7. Supplemental Lighting • What is supplemental lighting? • Artificial lighting • Plants need light for proper growth. The light spectrum range produced by artificial light enhances the natural light derived from the sun by many times over.

8. High Intensity Discharge Lighting System • Has traditionally been used only by commercial growers in large scale greenhouses. • The benefits of HID lighting are healthier seed starts, faster maturing plants, higher yield, and more spectacular flowering. • It can not only supplement sunlight, but also replace it during long winters where sunlight is in short supply. • Efficient and effective supplemental lighting system

9. Fluorescent Lighting • Cooler and more efficient that incandescent lights • Have a wide range of wavelengths and long life

10. Incandescent Lighting • Inefficient and gives off primarily infrared wavelengths. • They use a considerable amount of power for the little amount of light they emit. • Often used for photoperiod control. • Can be used to increase the day length

11. Light Comparison

12. Review • photoperiod • photoperiodism • energy curtains • shade curtains • short-day curtains • supplemental lighting • fluorescent lighting • high intensity discharge lighting system • incandescent lighting