Job offersmore »

Tweeting Growers

Last commentsmore »

Top 5 - yesterday

Top 5 - last week

Top 5 - last month

Exchange ratesmore »

Influencing plant growth with LED light

Plant growth can also be influenced by light. Dr. Dirk Ludolph from LVG Ahlem looks at the LED technology from which the horticultural sector expects results with regard to elongation growth, colouration and contained substances. Specialist editor Dr. Heinrich Dressler has summarised the findings.

Effects: photosynthesis and photoperiods cannot be clearly separated 
According to Ludolph it is not possible to clearly separate the effects between photosynthesis and photoperiods. In experiments in Ahlem with potted plants (poinsettias, begonias) the plants in the LED variants did not display better growth than the variants with high-pressure sodium vapour lamps. Some of the effects in other experiments could be explained by greater light intensity. According to Ludolph there were no specific photosynthetic effects.

Petunias display strong elongation growth under dark red light.

As the LED modules radiate little heat it is possible to place them close to stock. The advantages of LED are its energy efficiency and the specific spectral impact, says Ludolph. The interesting lamps from a crop technology point of view according to Ludolph are white (mixed light), blue (440 nm), light red (dark red, 660 nm) and dark red (far red, 730 nm). Blue light promotes elongation growth more, light red light mostly inhibits it and dark red light strongly promotes elongation growth.

LED: dark red light necessary for long-day plants
Dark red is necessary for long-day plants but not for short-day plants (such as petunias, calibrachoa and poinsettias). Petunias display strong elongation growth under dark red light and grow very compactly under light red light. Blue light promoted elongation slightly. In hedera light red light caused shorter internodes and shorter shoots. Bromeliads displayed more pronounced red leaf colouring under blue light and the flower stalks were more elongated on strawberries.

In poinsettias dark red light promoted elongation – this could perhaps be utilised in the production of stems. Longer steps from dark red light could also be advantageous in tulip forcing. Poinsettias were more compact after being provided with light red light between 5 pm and 5.30 pm (the ‘end of day effect’). It may be possible to save some of the inhibitor substances in poinsettias, says Ludolph, as they often grow too wide if they have none. For example inhibitor substances could be given twice at the beginning of cultivation, combined with one hour of red light from sunset onwards.

Influencing chrysanthemum growth with LED technology
In chrysanthemums and other summer crops LED had no effect on growth, as there is too much natural radiation in the summer for LED effects. The use of LED is primarily of use in autumn and spring.  

According to Ludolph LED does offer many control opportunities overall. The technology is well-developed and the light yield good. However because of the necessary investments this technology is more suited to specialist operations, says Ludolph. Users must pay attention to the spectrum that an LED lamp actually produces because the influence on the plants depends on this. Simple ‘hardware store’ lamps usually have a blue LED with a white filter while more expensive specialist lamps have two or three LED and therefore offer a broader spectrum.

For more information:
Poststraße 30
89522 Heidenheim
T: +49 7321 9594 290
F: +49 7321 9594 299

Publication date: 6/1/2018



Other news in this sector:

8/20/2018 Passively cooled LED offers bright, uniform light for all crops
8/15/2018 Listen to your roots
8/15/2018 UK: Cambridge scientist photographs tiny plants
8/14/2018 Wagagai in Uganda chooses Service Engine
8/10/2018 NL: New test facility for NovaCropControl
8/8/2018 How the cut flower industry could use AI to grow
7/20/2018 Programmable light spectra without loss of power
7/20/2018 "We’re capturing data we previously couldn’t"
7/20/2018 "It is a misunderstanding to think LED lights do not get dirty"
7/19/2018 Controlling greenhouse humidity during summer’s hottest months
7/19/2018 How MOT-proof is your grow lighting installation?
7/17/2018 Russian LED maker prescribes light recipes
7/13/2018 Hort Americas first North American distributor for 30MHz
7/12/2018 The quest for knowledge in indoor farming and new crops
7/12/2018 "Water by weight for superior hanging baskets"
7/11/2018 LED lighting: where are we now?
7/10/2018 Bloemencorso using modern tech for safety and traffic management
7/6/2018 "Add durability to your favorite watering tool"
7/5/2018 Australia: New heights for horticulturalists
7/4/2018 Cultivation floor and irrigation seamlessly integrated



Your article is very useful and helpful
Vijay, hyderabad, India - 7/18/2018 1:05:16 PM

Leave a comment: (max. 500 characters)

  1. All comments which are not related to the article contents will be removed.
  2. All comments with non-related commercial content, will be removed.
  3. All comments with offensive language, will be removed.

  Display email address

  new code