Potentials of indoor lettuce production in natural forest soil at limited watering

Abstract

Indoor farming in the global vertical farming market has been growing by more than 8% annually since 2010 and 31.6% growth is expected by 2025. It promises to be a possible future form of agricultural practices producing local, fresh, high quality, lower-carbon food year-round. Indoor farming experiment was designed to using LED and neon lights and water source of a dehumidifier. Lettuce (Lactuca sativa L. var. capitata) was grown for 12 weeks in a naturally available forest surface soil, including its native biodiversity and biological activity. Two different levels of water supply were used, full- at 66%- and half- at 33% of the total water-holding capacity (WHC100%) of soil. Some of the physical-chemical, and soil-biological parameters, such as dehydrogenase- (DHA) and fluorescein diacetate (FDA) enzyme activities and the most probable number (MPN) of fungi and bacteria were assessed prior to and after lettuce cultivation. Although the abundance of countable microorganisms decreased appreciably by the end of the lettuce experiment, the growth of plants could result in an enhanced soil-biological enzyme activity of the used natural soil. DHA increased 4.2-fold at drought condition, and 2-fold at the optimal water supply. One can conclude that used natural forest soil with great fertility and biodiversity potential can provide a good facility for the indoor lettuce cultivation. Reduction of water supply can be further optimized with the required biomass-production of lettuce.

Keywords

• natural soil
• soil-enzymes
• indoor gardening
• vertical farming
• sustainability