Lighting Systems to Increase Growth and Production
High Pressure Sodium Grow Lamps Improve Bud-Set, Increase Growth
Greenhouse growers around the world use high pressure sodium grow lights to improve bud-set, increase growth, and create artificial growing environments to guarantee production out of season, usually when prices are highest. In a greenhouse, supplemental growth lighting can be used on cloudy days, or to extend daylight hours in winter. Plants can be kept actively growing all year round, making out of season crops possible and boosting your income. Dormancy can be prevented in some crops, and winter fruiting can be induced by providing extra light during autumn.
How Would Your Greenhouse Benefit from Supplemental Growth Lighting?
Indoor lighting controls the length of daylight hours, enabling the greenhouse grower to force flowering out of season.
In the production of roses, for instance, production decreases substantially in late autumn, winter and early spring. There are fewer buds and many buds don’t flower. This is mainly due to lack of light.
The answer is Assimilation (photosynthesis) Lighting, which stimulates the growth of young shoots and new buds by higher light levels, and stimulates the growth of already developed buds by giving more hours per day of light.
The duration of light and dark periods (photoperiodism) are also important to a plant’s growth and reproduction. Growth photoperiods for vegetables are 16-18 hours a day while , photoperiods are usually 10-14 hours a day for flowers. During that stage of growth, lights should be left on as long as possible because strong initial growth makes the young plants healthier and more resistant to disease, which ultimately produces a higher crop yield. As the plants mature, light duration should be reduced.
Timed lighting is often used to trigger flowering in photoperiod sensitive plants like Chrysanthemum & Poinsettia, but normally greenhouse growers use simple and cheap incandescent bulbs which do not increase growth.
Special Growth Lighting Increases Yield in Greenhouse Crops
High Intensity Discharge (HID) lighting allows growers to increase crop yields, bring crops to market on schedule and produce quality crops out of season. Horticultural lighting systems allow you to extend the growing season by providing your crops with the light spectrum and intensity almost equivalent to the sun. The sun’s spectrum contains visible light in every colour of the rainbow, blue light appears at one end of the spectrum, red light at the other. Plants appear green because they reflect green light, while absorbing the other colours of the spectrum. Photosynthesis is most pronounced in the red (600-680nm) and blue (380-480nm) wavelengths of light.
Blue Light stimulates the hormones that trigger growth and inhibit dormancy. Blue light encourages chlorophyll production more than any colour, which promotes photosynthesis, resulting in thick leaves, solid stems and strong vegetative growth. Blue light controls leaf fall and fruit ripening. It also encourages plant foliage to grow towards the light source (phototropism). Blue light also serves to keep plant growth compact and shapely by minimising the distance between internodes (branches). Blue light is most pronounced during the spring and summer months when the sun is highest in the sky.
Red Light is important for plant reproduction. It regulates seed germination, root development, tuber and bulb formation, flowering and fruit production. Red light is also responsible for triggering dormancy in some plants. The red portion of the spectrum is essential to plant growth, and encourages the flowering, fruiting and reproductive stages. Red light is prominent in the autumn and winter months when the sun is lower in the sky.
HID lighting systems are designed to cover these specific wavelengths. There are two types of HID lighting, which emit different colour spectra, Metal Halide (MH) and High Pressure Sodium (HPS).
Metal Halide Lamps These grow lighting systems are designed to provide the maximum output of photosynthetically active radiation (PAR) for the amount of power consumed. MH grow lamps emit light strongly in the white/blue spectrum and are best used as a primary light source if little or no sunlight is available. This type of lamp is ideal during the vegetative growth stage. The MH lamps help to keep plants shorter, with more compact vegetation and the plants will be stronger, better able to resist disease, and are generally more productive. MH lighting systems are best for mostly leafy crops such as lettuce and other vegetative crops.
High Pressure Sodium Lamps HPS growth lamps emit light in the orange/red spectrum and are best used for secondary or supplemental lighting in conjunction with natural sunlight. This type of lamp produces exaggerated flowering and fruiting during the plants reproductive stage. HPS lighting systems are best used for growing flowering plants, and can increase flower production by 20% or more.
Find out how Powerplants’ Grow Light Systems can make your greenhouse crops healthier and more productive.
Contact us today for a quote.
