Different purposes of light in horticulture

The use of light in horticulture has vastly increased in recent years. Knowledge of how light affects crops is still evolving, but what is clear is that light can benefit both crop health and yields. Different wavelengths have varying benefits and purposes in horticulture, thus the versatility that LED technologies offer is ideal.

Plant growth and yields.

One of the most common reasons that growers implement horticultural lighting is to increase plant yield, speed and widen growing windows. Artificial lighting is particularly useful in applications where natural sunlight is lacking. For example, in greenhouses on overcast days or during the winter months when sunlight hours are shortened. By using horticultural lighting, growth opportunities have expanded, and crops can be grown within conditions that were not previously viable.

• Sole-source lighting: More commonly growers are getting creative with where they can grow crops. In urbanised areas, vertical farms have been gaining traction, such applications can be entirely indoors without access to natural sunlight. Sole-source lighting refers to the delivery of light to plants that do not also receive light from the sun. For artificial lighting in such settings, growers are turning to LED, which provide multiple benefits, whilst minimising ongoing running costs.
• Supplemental lighting: This style of light implementation works alongside natural daylight to supplement and provide additional light to crops. This could be by delivering a full spectrum of wavelengths outside of natural growing hours to increase the growing window. Or by providing plants with additional quantities of specific key wavelengths during natural daylight hours to increase their positive effects on the quality of plant growth. This method is often used for crops that need lots of light, like tomatoes, grown in greenhouses, particularly during winter months.
• Photoperiodic lighting: This method is more application-specific, as it does not typically encourage photosynthesis and plant growth. Rather, it promotes and regulates flowering and certain phases of plant development. This is useful for ornamental crops, such as those used in landscaping. With lighting, growers can encourage these plants to produce flowers when desired, by providing low-intensity light to plants that mimics natural light and dark cycles.

The Treviso grow light is designed for easy installation in vertical farms, racks, and benches. With a full spectral output, plants can be exposed to multiple wavelengths to assist with plant quality and growth speed. The built-in lens provides a 120-degree coverage, meaning that large areas can be illuminated with a single light. Treviso is an ideal replacement for traditional T5/T8 lamps.

Learn more about the effects and benefits of different light wavelengths here: full spectrum light, red light, and blue light.

Sterilisation and removal of harmful bacteria.

Perhaps less commonly discussed, are the benefits and applicability of light for plant sterilisation and the removal of harmful bacteria. No matter what the crop, growers all encounter the common issues of pests and disease, including black spots, powdery mildew, and grey mould. For decades, growers have been using chemical pesticides to protect plants from such problems. But these chemical contents of these solutions can have a negative impact on the natural soils and water supplies. Moreover, regular use of pesticides could lead to contamination of the plants themselves.

So now, UV light can be applied directly to plants to combat these issues and destroy harmful bacteria and pathogens, without negatively impacting the plant itself. Plants consist of organised multilayer tissues, whilst pesty problems structurally differ. Fungi, for example, consist of mono-layered mycelia. Bacteria have significantly less complex structural organisations, as many are single-cell. So, when UV is applied the effects on such micro-organisms in comparison to the plant itself fundamentally differ. Fungi and bacteria will be destroyed, leaving the plant be. Though caution is still needed, as too much exposure to UV radiation can still burn and damage plants. The wavelength applied and duration of exposure should be tailored based on the plant’s specific needs.

UV wavelengths can even be applied to plant water supplies for additional sterilisation. When applied to water, UV light will not alter the pH or chemistry of the water, but it will neutralise any harmful organisms to growers such as fungi, viruses, moulds, and mildew. 

The Amalfi disinfection light allows for efficient sterilisation, eliminating 99.9% of bacteria, spores, and viruses in only 10 seconds. An ideal solution for protecting target plants from diseases and pests. The Amalfi combats powdery mildew, funguses, viruses, and bacteria on plants.

Learn more about the effects and benefits of ultraviolet wavelengths here.