Controlled environment agriculture (CEA) represents the convergence of engineering, plant science, and data analytics to create optimal growing conditions for crops regardless of external climate. Greenhouse horticulture and vertical farming are both part of Controlled Environment Agriculture (CEA) . Over the past 40 years, productivity in CEA has increased substantially, more than doubling for tomato and sweet pepper, as a result of improved greenhouse technology, advanced cultivation techniques, improved knowledge for climate control, and genetic improvement . Controlled environment agriculture enables consistent, high-quality yields with significantly reduced resource inputs compared to traditional field production, making it a critical solution for global food security challenges.

Modern CEA systems integrate sophisticated environmental control technologies to optimize plant growth and resource efficiency. Dynamic plant spacing can improve light use efficiency, with research showing that gradually decreasing planting density from 100 to 19 plants per m² more than doubled the yield compared to constant 19 plants m⁻² without negative consequences for fruit quality . Dynamic spacing is common practice in ornamental pot plant production and for raising young plants, and can be very well automated using mobile gutter systems . Energy use efficiency has improved significantly, with Dutch greenhouse tomato production achieving about 2 kg tomatoes per m³ gas, and research demonstrating tomato production of 75 kg m⁻² using only 12 m³ natural gas and 10 kWh electricity in a greenhouse with several screens and active dehumidification .

Light spectrum management has emerged as a critical factor in CEA productivity. Light spectrum affects plant morphology including elongation, leaf area development, and flowering, more than photosynthesis rate . For supplementary red-blue light in greenhouses, 6-12% blue is sufficient, whereas a high fraction of blue (24%) resulted in a lower tomato yield . Far-red radiation has received significant attention, as it does not drive photosynthesis alone but when combined with shorter wavelengths it does . Absorbed far-red photons are equally efficient for canopy photosynthesis when applied in combination with 400–700 nm photons up to ~30% of the total photon flux, leading to the proposal to extend the PAR wavelength region to 750 nm (ePAR) . Additional far-red has also been shown to increase tomato yield as a result of improved assimilate partitioning to the fruits, caused by a higher fruit sink strength .

Hydroponic cultivation systems are central to modern CEA operations, enabling precise nutrient delivery and water management. Soilless cultivation technology refers to growing high-value horticultural crops in different soilless medium which is totally devoid of soil, including grow bag technology, pure hydroponics, aeroponics and aquaponics . The nutrient solution is a balanced mix of major nutrients—nitrogen, phosphorus, potassium, magnesium and sulphur—and a very low concentration of minor nutrients or trace elements including copper, boron, iron, manganese, molybdenum and zinc . The pH is crucial, with a pH of 5.8-6.2 usually aimed for, requiring a meter or test papers for monitoring . Popular soilless growing media used are cocopeat, perlite, vermiculite, rockwool, cocochip, sand, stonechip etc. in different combinations or alone itself .

The integration of sensors, automation, and IoT is transforming CEA and hydroponic systems. Sensors are commonly used by growers for overall supervision and management of the growing system for high-value vegetables, flowers, spices and greens . The automation of tasks through the utilization of agricultural robots and IoT facilitates a reduction in the necessity for manual labor and enables the continuous monitoring and adjustment of growing conditions . Mini-plant factories are CEA systems for small-scale indoor crop production, typically utilizing hydroponics or aeroponics to cultivate plants without soil, often incorporating artificial lighting, microclimate controllers, and nutrient management systems . Mini-plant factories offer benefits including the ability to produce consistent and high-quality vegetables within a small space, reduced dependency on external suppliers, and the potential for generating supplemental income . The future of CEA lies in autonomous control and digitalization of crop growth and development, ensuring that controlled environment agriculture and hydroponic cultivation systems will continue to drive sustainable food production worldwide.