Harvest better crops with LED grow lights

Harvest better crops with LED grow lights

Plants are sensitive to light. This sensitivity is crucial in their survival, and whether they are planted in or outdoors, they respond to light intelligently. In vertical farming, where growers use artificial light to simulate natural light rhythms, custom LED grow lights play a central role in promoting plant growth and enhancing their life quality. In some cases, perfecting a plant’s ‘light recipe’ can even cultivate better harvests in terms of yield, quality, and taste.

A plant’s life cycle is generally categorised into four main stages—seeding, germination, growth, and harvest. Aside from having a life cycle, plants also have light cycles, which are closely related to their growth stages.

Plant light cycles are simple on traditional farms where crops are grown outdoors and horizontally in an open field. They follow the rhythm of the day and closely adhere to the natural cycle of sunlight, photosynthesising after sunrise and resting after sunset.

In vertical farming or other indoor farming processes where plants rely wholly on artificial light to thrive, growers must set light schedules. Instead of following the natural light conditions of those outdoors, many vertical farmers have discovered that plant light cycles can be optimised with LED grow lights to extend growing seasons and create more varied, bountiful, and nutritious harvests.

Responses to light in plants

Even though building a vertical farm requires more than just optimised lighting, light plays a central role in plant development.

Firstly, plants are extremely sensitive to light, and those grown in the shade will always veer towards light sources. This is due to their need to absorb light for photosynthesis, an essential process through which they make food for growth.

Plants are also able to differentiate between illuminations of different colours. They absorb these lights at different rates within the full white light spectrum and use each coloured light for a specific purpose. For example, blue light encourages leaf growth in plants, while red light helps plants bud and flower.

Finally, the biological sensitivity in plants allows them to make distinctions in light duration and intensity. Plants grown outdoors can detect different wavelengths in sunlight and, along with air temperature and humidity, determine the time of day and year, prompting them to germinate, flower, or bear fruit accordingly. This explains why flowering plants, and fruiting and rooting crops, have specific seasons in which they thrive.

How to harvest better crops with LED grow lights

LED grow lights can change and promote the growth of plants through light quality, intensity, and illumination time.

As vertical farmers optimise each of these elements to suit their crops’ needs, they have discovered that optimisation can lead to higher yields and higher-quality crops that are more nutritious.

Light quality

LED grow lights can improve efficiency in vertical farming and other indoor farming activities through their high quality of light and the wide array of colours in which they come.

Photosynthesis plays a central role in plant growth. While the process relies on light absorption, research has shown that plants do not respond to the full spectrum of colour present in sunlight or white light imitations of sunlight.

Instead, vertical farmers have learned that absorption peaks in the red and blue regions of the spectrum, and these regions strengthen and promote structural development in plants. Having more red and blue LEDs installed in farms can shorten growth periods and increase plant quality. This creates a more bountiful harvest.

At LED iBond, we offer high-quality deep red and royal blue LEDs that are compact in size and easily customisable in arrangement. At only 5mm each, a dozen red and blue lights can be combined with our pure white LEDs in one intelligent shelf and rack system comprised of a sleek shelf and its supporting component, a custom-made rack.

By customising LED grow lights to the photosynthesis response of plants, vertical farmers can increase yields and improve harvest quality.

Light intensity

Vertical farmers can also harvest better crops with LED grow lights by adjusting their light intensity.

Research has shown that light intensity should increase suitably and following the growth stages of plants. This is crucial during the plant’s flowering and fruit-bearing period, as light intensity can affect the harvest quality of fruiting crops.

A case study conducted by Wageningen University and Research: Greenhouse Horticulture supports this theory. Studying tomato varieties and their responses to various intensities of light, scientists at Wageningen UR have learned that the suspension of special LED modules between tomato clusters in plants and exposing them to extra light has positive effects on their growth.

The LED modules emitted light levels similar to that of a quarter of the natural light intensity on a sunny day, and they were placed directly beside the tomato clusters. This study was conducted in a climate-controlled environment for 13 days.

In one of the tomato varieties, the scientists discovered that the tomatoes exposed to extra LEDs contained up to twice as much Vitamin C as those of the same species that did not receive the extra light, doubling their nutritious value.

However, stronger light intensity is not necessarily better for the growth of plants. If light intensity goes beyond a plant’s light saturation point and lights are placed too close to the plant itself, they may end up scorching plant surfaces and wasting the grower’s electricity.

Luckily, LEDs typically have much lower heat emissions than traditional luminaires such as fluorescent and incandescent lights. With our patented heat management technology, our lighting equipment also reduces the amount of excess heat from our LEDs.

Nevertheless, there is a good rule of thumb to prevent your plants from being burned. You can place the back of your palm on top of the plant leaves and beneath the light source. If your hand feels hot after a while, it is best to lower the light intensity or increase the distance between light and plant.

Illumination time

Plants regulate their own grow cycles by the amount of illumination time and when they receive light. This is called photoperiodism, and it is a physiological response in plants that causes them to adjust growth rates according to light and dark periods.

This adjustment affects a plant’s flowering, budding, and vegetating periods as photosynthesis occurs in the presence of light. Knowing this, vertical farmers can optimise the length and duration of illumination to what suits their crops best.

Generally, it is advised to leave LED grow lights on for between 12 to 16 hours a day to maximise plant growth while also giving them sufficient time to rest. In the dark, plants can use the food they have made and stored from photosynthesis to grow to prepare for flowering.

Vertical farmers can also extend vegetable growing seasons by adjusting illumination time and farm climate. Cabbage, kale, and spinach are cool-season vegetables. In traditional farming, their seeds are planted in cold soil weeks before springtime when the soil is still cold. On the other hand, snap beans and tomatoes are warm-season vegetables and grow during the warmer seasons when there are more daylight hours and a warmer climate.

In vertical farms, growers can set temperatures to mimic different seasonal climates, and they can toggle LED grow lights to turn on and off according to each season’s daylight hours. Full Internet of Things (IoT) integration in our LED lighting equipment makes this easy.

Our lighting shelves and panels are compatible with third-party devices such as temperature, motion, and time sensors. Configured in one central system, LED grow lights can turn on and create full sun conditions for hours, and growers can turn them off remotely to create dark environments when needed.

Having complete control of farm climate and illumination time means that growers can cultivate any crops they wish at higher rates and meet demands for local consumption.

Harvest better crops today

Plants are intelligent life forms with sophisticated responses to light. As vertical farming takes place indoors, growers have the opportunity to optimise light sources to best cater to their crops’ needs. This can lead to bigger harvests of more high-quality crops all year round.

The advantages do not just stop there, either. Efficient vertical farm management with custom LED grow lights can also lead to lower operational costs. For more information on our lighting solutions and the benefits of LEDs, please contact Henrik Fabricius, VP Sales, Vertical Farming, at (+45) 8161 7810 or via email at hfa@ledibond.com.