11/2021 Leveling Up Indoors – How Multi-Tier Cultivation with LEDs is Revolutionizing Agriculture
Once upon a time, farming was limited to outdoor growing spaces with fertile soil. Nowadays, as arable land becomes limited and expensive around large population centers, the promises of vertical farming are becoming a reality. While legacy lighting systems–such as HID and HPS–present major challenges for vertical farms due to their high thermal output, the advent of advanced LEDs has begun to fulfill and exceed the expectations of past decades. As cities continue to grow, so too will the demand for local, multi-tier, indoor farming using LEDs.
Indoor agriculture depends entirely on artificial lighting to supplant natural sunlight. While HPS lighting has made multi-tier, or multi-level, indoor agriculture possible for two decades, its high amount of thermal radiation creates a multitude of problems for growers, including varying microclimates, over-heating and crop death, dehumidification and temperature fluctuations from venting, among others. The costs of repairing and replacing HPS lights also cut into profits, not to mention suboptimal PPFD levels and an inability to control an HPS bulb’s intensity.
Enter Stage Left: Light Emitting Diodes (LEDs).
LEDs have revolutionized indoor, multi-tier farming for a variety of reasons, but three primary factors stand out: compared to legacy systems, Fluence LEDs produce more light with less heat using the same electrical input.
The lower infrared (IR) heat output of LEDs (coupled with their potential for arrangement in wide arrays) allows farmers to hang lights closer to the canopy than they could with legacy lighting systems. Not only are farmers achieving higher PPFD levels with LEDs, but they are also increasing their existing grow spaces between 200-300% by implementing two-or-three-tier benching. Growers are discovering that the higher capital expenditures (Capex) of a vertical farming installation–mobile benching, air delivery systems, irrigation, and new genetic selections-are quickly offset by the greatly increased revenue.
There are several challenges for vertical farmers to consider as they double or triple their crop production: air circulation, spacing and workflow, light distribution, and irrigation and wastewater are critical components of indoor facilities, especially those with multiple levels. It is also important to note that there is quite a big difference between a two-tier and three-tier cultivation system.
Air Circulation - Packed-in plants require air movement that cannot be achieved with circulating fans alone. The plants, lights, and racks obstruct natural airflow and CO2 supplementation. Air ducts within the racks are necessary to move conditioned air throughout the canopy on all levels. It is important to be aware of temperature stratification. For multi-tier rooms, inner-rack delivery airflow systems are critical for moving air around benching and lights and for preventing stagnation. The supply of air from the HVACD - which is colder and drier than the room’s setpoints - should be mixed with the ambient air to achieve homogeneous temperature before delivering it into the canopy.
Spacing and Workflow - A three-tier installation leaves less overhead space for worker access than do two-tier installations. Added plumbing and air ducts further reduce overhead space, requiring careful planning to ensure workability.
Light Distribution - Fixtures such as the Fluence SPYDR can provide corner-to-corner light distribution with minimal spillover. Hanging height and racking height are also crucial for consistent PPFD levels across the canopies.
Irrigation and Wastewater - Plumbing for irrigation lines and wastewater management require careful planning. Pumps will need to perform more work to lift hydroponic solution to each rack, and a drainage system will be needed to collect spill off.
While vertical farming presents new challenges for modern growers, it also promises to lead and feed the future. LED solutions have alleviated the struggles of multi-tier growing and have made the promises of last century a more-than-profitable reality today. Fierce competition and rising real estate costs in the U.S. and abroad is forcing growers everywhere to level up both their facilities and lighting systems to meet demand.
If you are interested in retrofitting your facilities with LEDs, or a multi-tier system, or if you simply want to know more about indoor growing and vertical farming, contact Fluence experts today or read our comprehensive Indoor Retrofitting Guide here.