Abstract: This article examines greenhouses, vertical farms, and container-based growing systems through their biological, energy, and resource balances. Rather than identifying one universally superior solution, it highlights how crop physiology, external climate, environmental-control requirements, and project objectives should guide technology selection. A multidisciplinary, system-level approach is therefore essential for designing scalable and resource-efficient Controlled Environment Agriculture facilities.
Greenhouses, vertical farms, and containers are often presented as alternative models to conventional agriculture. From an agronomic and engineering perspective, however, framing the comparison in these terms is incomplete and sometimes misleading.
The real difference becomes apparent when analysing mass and energy balances. In a closed environment, the energy introduced by lighting and other systems must ultimately be removed. Some of it becomes sensible heat, while a significant proportion is converted by the crop into latent heat through leaf transpiration.
In simplified terms:
Energy input → growth + sensible heat + transpiration
In a vertical farm or container, the water vapour released by the crop does not simply disappear. It must either be removed through ventilation or condensed by the HVAC system. Dehumidification is therefore a direct consequence of plant physiological activity, not merely a building-related issue.
Graamans et al. applied the Penman–Monteith model to the energy balance of a lettuce crop grown in a closed environment. Their findings showed that latent heat flux can represent the largest energy flow within the system and, under certain conditions, may even exceed the energy supplied by the lighting system.
This means that climate-system sizing cannot be based solely on room volume, lighting power, and target temperature. It must also account for leaf area, crop development stage, PPFD, VPD, and expected transpiration.
The energy comparison between greenhouses and vertical farms also changes depending on the external climate and the performance indicator being considered.
In a study on lettuce production across different climatic regions, Graamans et al. estimated purchased electricity consumption of 247 kWh per kilogram of dry matter in a plant factory, compared with values ranging from 70 to 211 kWh in the greenhouses analysed.
However, the plant factory achieved greater efficiency in its use of water, CO₂, and land area. Therefore, no system was inherently better in absolute terms: the outcome varied according to the resource being considered.
This is why the first question should not be, “Greenhouse, vertical farm, or container?” but rather, “Which biological conditions must we provide, and which resources do we want to optimise?”
Only then can we determine how much to rely on the external climate, how extensively to isolate the system, how much energy to purchase, and what level of environmental control is genuinely necessary.
Technology does not come before the project. Rather, the design and operating principles of the technology should emerge from the project as a whole. By starting with the project’s biological, energy, and economic balances, it becomes possible to determine which technology actually makes sense.
In conclusion, without detracting from fully developed cultivation systems such as the advanced vertical farms and greenhouses offered today by leading manufacturers, a well-designed container can help resolve several initial uncertainties and pave the way for clearly defined industrial projects from their earliest stages.
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