Articles
Economics and resource efficiency of apartment-scale vegetable growing in Singapore
Article number
1429_39
Pages
317 – 324
Language
English
Abstract
The COVID-19 pandemic sparked a global surge in apartment-grown vegetables.
However, there remains a gap in analyzing the economic feasibility and resource efficiency of small-scale urban growing compared with commercially-grown food purchased at retail.
In this study our objectives were to 1) quantify the resources and economics of apartment-scale urban growing in Singapore, and 2) compare yield and cost between growing systems and light environments.
At Gardens by the Bay in Singapore, two experiments were conducted growing Ocimum basilicum (sweet basil), Brassica rapa (pak choi), and Brassica oleracea (kailan). The experiments combined the three plant species in each growing system.
Growing systems included apartment-scale hydroponic systems versus container substrate, and environments were either indoors under sole-source LED lighting in an air-conditioned room to simulate an apartment, or in an outdoor partially-shaded environment to simulate a patio.
The costs of water, nutrient, and electrical inputs, and the purchase and operating costs of the growing systems were quantified to determine the cost per kilogram of harvested yield.
In both experiments, the harvested yields were more than twice greater when plants were grown indoors under sole-source lighting and air conditioning compared with outdoors under sunlight, in addition to improved aesthetic quality and lower pest pressure.
Yields tended to be greater in hydroponic systems versus substrate, and the highest yielding species was pak choi.
Plant water and nutrient requirement (in L of water or g of N, P, and K kg‑1 fresh weight yield) was consistently lower (i.e., more efficient) in indoor systems than in outdoor systems.
However, growing systems indoors incurred higher electrical and monetary cost despite the higher yields.
Producing pak choi, kalian, and basil in the tested small-scale systems was not as cost-effective as purchasing at a grocery store.
For example, the cost to produce pak choi in a hydroponic system was $ 36.15 kg‑1, twice the cost of buying locally at $ 14.75 kg‑1. Based on our results, hydroponic indoor systems were easily managed with consistent and high yields.
However, outdoor growing under sunlight in container substrate had the lowest initial and operating cost per system.
Apartment-scale urban growing helps connect urban growers to nature and their food supply, can provide enjoyment, mental health and other benefits, but is not a significant contribution to food security.
However, there remains a gap in analyzing the economic feasibility and resource efficiency of small-scale urban growing compared with commercially-grown food purchased at retail.
In this study our objectives were to 1) quantify the resources and economics of apartment-scale urban growing in Singapore, and 2) compare yield and cost between growing systems and light environments.
At Gardens by the Bay in Singapore, two experiments were conducted growing Ocimum basilicum (sweet basil), Brassica rapa (pak choi), and Brassica oleracea (kailan). The experiments combined the three plant species in each growing system.
Growing systems included apartment-scale hydroponic systems versus container substrate, and environments were either indoors under sole-source LED lighting in an air-conditioned room to simulate an apartment, or in an outdoor partially-shaded environment to simulate a patio.
The costs of water, nutrient, and electrical inputs, and the purchase and operating costs of the growing systems were quantified to determine the cost per kilogram of harvested yield.
In both experiments, the harvested yields were more than twice greater when plants were grown indoors under sole-source lighting and air conditioning compared with outdoors under sunlight, in addition to improved aesthetic quality and lower pest pressure.
Yields tended to be greater in hydroponic systems versus substrate, and the highest yielding species was pak choi.
Plant water and nutrient requirement (in L of water or g of N, P, and K kg‑1 fresh weight yield) was consistently lower (i.e., more efficient) in indoor systems than in outdoor systems.
However, growing systems indoors incurred higher electrical and monetary cost despite the higher yields.
Producing pak choi, kalian, and basil in the tested small-scale systems was not as cost-effective as purchasing at a grocery store.
For example, the cost to produce pak choi in a hydroponic system was $ 36.15 kg‑1, twice the cost of buying locally at $ 14.75 kg‑1. Based on our results, hydroponic indoor systems were easily managed with consistent and high yields.
However, outdoor growing under sunlight in container substrate had the lowest initial and operating cost per system.
Apartment-scale urban growing helps connect urban growers to nature and their food supply, can provide enjoyment, mental health and other benefits, but is not a significant contribution to food security.
Authors
C. Anderson, P. Fisher
Keywords
basil, hydroponics, kailan, leafy greens, pak choi
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