“Those within the commercial Ag side of vertical farming, we’ve seen a $1 billion dollar investment in the past three years," Tim Knauer, Horticulture Specialist at Fluence by OSRAM says. According to Tim, focusing on your lighting is crucial as it has a direct impact on plant production. "It’s also going to be a major portion of a grower’s Capital Expenditures,” he explained last week in the online webinar ‘Vertical Farming's Vital Component: Lighting”, in what he explained what growers and investors should look for and why lighting is the most valuable input of a crop.
Tim explained how there are various trends encouraging the evolvement of vertical farming industry. “By a higher demand in local and fresh produce and through technological advancements, vertical farming today has become possible, also due to advancements in LED technology and automation. There’s smarter horticulture designs: with more vertical farms, growers are figuring out the best layouts.”
Tim Knauer, Horticulture Specialist at Fluence by OSRAM
A plant response to light
And then there’s lighting. "The major portion of Capital Expenditures of a grower comes from lighting, and the vertical farming industry has a high upfront CAPEX," Tim says. "“Lighting also has a direct impact on plant production. The quality/quantity of lighting drives the yield and as we all know, increased yields give the opportunity for an increased profit, and a quality improvement gives flavor and health benefits.”
There are three aspects of lighting affecting growth, Tim says: the quantity (intensity), the quality (spectrum) and the duration (photoperiod). “Lighting can manipulate the plant shape, flavor, nutrition, and medicinal properties. The right light intensity and spectrum have a direct impact on plant consistency as well. Meaning, if the lighting uniformity and consistency are good, automatically the plant uniformity and consistency will be good.”
On the production site light has two functions. “Firstly, plant growth which is due to the light quality and quantity, feeding the biomass production. Secondly, the plant development which is controlled a little more by the light quality spectrum and photoperiod. All these aspects interlink all the time, depending where located in the plant growth cycle.”
Nowadays it’s getting more common to use PPFD (Photosynthetic Photon Flux Density) and DLI (Daily light integral ) as the measurement of light, because they’re easily in changeable with each other. “If the preferred crop PPFD level is known, the DLI can easily be calculated. Or knowing your DLI, the crop PPFD can be calculated as well”, Tim says, adding how maximizing the DLI has great benefits.
“Maximizing DLI and taking advantage of all light that can be provided to the crops will increase production or yield. If you’re decreasing the cycle time, if having consistent and uniform light, the crop will grow consistently and uniformly. This results in more insights on the harvesting periods and by squeezing in more cycles per year which helps increase production. It improves the quality and consistency of crops. Then increasing biochemicals benefit through higher consistent lighting and higher benefits as far as nutrition and vitamin content. These four benefits increase profits which we are all going for and eventually decreasing inputs,” Tim noted.
Different PAR spectra
Tim explains how the spectra chosen will affect the crop growth. Over the last decades, Fluence has conducted extensive research into the effects of a spectrum on a crop.
- Blue light. This affects morphology (compactness), thus the higher the blue light in the spectra, the longer stomates will stay open. This results in increasing transpiration. Next to that, it also affects leaf pigmentation, the leaf colors.
- Green light. Green light offers better transmission through the canopies. It also contributes to photosynthesis that the red and blue light normally cannot reach.
- Red light. It does not only drive photosynthesis, but it can also induce germination, flowering and ripening.
- Far red light. This lighting can increase leaf area, the internode length and the petiole length.
Why focus on lighting?
So what should an investor be looking for in lighting? A lot – Tim says. “It’s a business strategy consideration that has direct impact on the plant production, also lighting impacts your decision on every environmental factor. By deploying the right strategy and equipment, upfront you will ensure the highest implant quality and yield of your crop."