1 Introduction

Hydroponic cultivation has gained prominence as a viable and sustainable alternative to traditional soil-based agriculture, offering advantages such as optimized resource use, spatial efficiency and the potential for year-round production under controlled environments (Pomoni et al., 2023; Singh et al., 2024). In such systems, light is not only a vital energy source for photosynthesis but also serves as a primary environmental signal regulating plant growth, morphogenesis, metabolism and stress adaptation (Paradiso and Proietti, 2022).

Unlike field-grown crops that experience fluctuating and often suboptimal light conditions, hydroponic systems provide a unique opportunity to manipulate light quality (spectral composition), intensity and photoperiod with high precision. This capacity for control allows researchers and growers to tailor lighting strategies to the specific physiological needs of crops, potentially enhancing productivity and nutritional value (Olle and Viršile, 2013; Mitchell et al., 2015).

The advent of light-emitting diode (LED) technology has revolutionized artificial lighting in controlled environment agriculture (CEA). LEDs offer the ability to emit narrow wavelength bands with low heat output and high energy efficiency, enabling fine-tuned photobiological responses in plants (Bourget, 2008). Numerous studies have investigated the effects of different light spectra, particularly red and blue light, on plant morphology and photosynthesis, but a comprehensive synthesis focusing on photobiological responses in hydroponically grown crops remains limited.

Furthermore, recent evidence suggests that light quality can modulate the biosynthesis of secondary metabolites such as flavonoids, terpenes and antioxidants (Dou et al., 2017), as well as influence tolerance to abiotic stresses including salinity, drought and thermal fluctuations (Dou et al., 2017; Hasan et al., 2017). These responses are particularly relevant in hydroponic systems, where environmental parameters can be fine-tuned to optimize both plant health and functional quality. This study aims to provide an integrative overview of how artificial light quality affects plant photomorphogenesis, secondary metabolism and abiotic stress responses in hydroponic systems. We also discuss emerging technologies that enable dynamic and spectrum-adaptive lighting strategies and explore their potential in precision agriculture applications.

2 Fundamentals of Photobiology in Plants

Light is a fundamental environmental signal that regulates not only photosynthesis but also a wide array of developmental and metabolic processes in plants. Through the perception of specific wavelengths, plants adjust their growth patterns, morphology, resource allocation and stress responses in a process known as photomorphogenesis (Wang et al., 2022). Understanding the photobiological basis of these responses is essential for optimizing artificial lighting strategies in hydroponic systems.

2.1 Photoreceptors and their spectral sensitivity

Plants possess specialized photoreceptors that absorb specific portions of the light spectrum and initiate signaling cascades:

Phytochromes are chromoproteins that perceive red (R: 620-700 nm) and far-red (FR: 700-750 nm) light (Wang et al., 2022). They control seed germination, stem elongation, shade avoidance and flowering. Phytochrome-mediated responses depend on the red:far-red light ratio, a critical indicator of canopy density and competition (Legris et al., 2019).

Cryptochromes and phototropins absorb blue (B: 400-500 nm) and UV-A (320-400 nm) radiation. Cryptochromes are involved in photoperiodic flowering, hypocotyl inhibition, and circadian clock regulation, while phototropins (control phototropism, chloroplast relocation and stomatal opening (Li and Yang, 2007).

UVR8 is a unique UV-B photoreceptor that perceives short-wavelength radiation (280-315 nm) and triggers protective responses including the induction of flavonoid biosynthesis, ROS scavenging enzymes and DNA repair mechanisms (Yin and Ulm, 2017).

These photoreceptors not only regulate specific processes individually but also work in concert to coordinate growth, resource allocation and adaptation to environmental stimuli. Their activity underlies many of the photobiological responses observed in hydroponic crops, as will be discussed in subsequent sections.

2.2 Photosynthesis and the action spectrum

Photosynthetically active radiation (PAR: 400-700 nm) encompasses the range of wavelengths used by photosystems I and II to drive electron transport and CO₂ fixation. Among these, red and blue wavelengths are the most effective for stimulating photosynthesis due to their strong absorption by chlorophyll a and b (Wimalasekera, 2019).

However, green light (500-570 nm), traditionally considered less important due to lower chlorophyll absorption, has gained renewed attention. While not as efficient on a per photon basis, green wavelengths can penetrate deeper into leaf tissues and inner canopy layers, thus supporting photosynthetic activity in shaded leaves, especially in dense or multilayered hydroponic systems. This spatial complementarity enhances whole-plant photosynthetic performance when green light is used in combination with red and blue (Smith et al., 2017).

Understanding the action spectrum, the relative quantum efficiency of different wavelengths for photosynthesis, enables precise tailoring of light spectra in artificial lighting systems. In hydroponic setups, this is particularly valuable to maximize light-use efficiency (LUE), optimize biomass accumulation and reduce energy costs, especially when combined with spectral tuning technologies.

2.3 Photobiological responses in hydroponic contexts

In hydroponic systems, the absence of soil and the use of controlled environments allow the isolation and manipulation of light as a single variable, making it an ideal platform to investigate photobiological responses. Under these conditions, plants often display heightened sensitivity to spectral changes due to the stability of other growth factors (Dou et al., 2017).

These responses are mediated by specialized photoreceptors, including phytochromes, cryptochromes, phototropins and UVR8, which together orchestrate a wide range of physiological processes such as seedling de-etiolation, stomatal regulation, and flowering (Folta and Carvalho, 2015).

Recent research in indoor hydroponic systems has examined how varying light intensities, particularly under controlled red and blue LED spectra, influence plant growth and quality. In a study involving basil (Ocimum basilicum L.) and lettuce (Lactuca sativa L.), increasing the photosynthetic photon flux density (PPFD) from 100 to 300 μmol/m²/s LED to a progressive rise in biomass accumulation, with optimal yield observed at 250 μmol/m²/s. Beyond this level, no additional yield gains were reported. Importantly, at 250 μmol/m²/s, lettuce exhibited significantly higher antioxidant activity, as well as increased levels of total phenolics and flavonoids. These findings suggest that moderate enhancements in light intensity not only maximize biomass production but also improve the nutritional quality of leafy vegetables grown in controlled indoor environments (Pennisi et al., 2020).

Moreover, manipulating the red:far-red ratio in vertical farming setups can regulate shade-avoidance responses, affecting plant height, leaf expansion and resource partitioning, which has direct implications for optimizing space and uniformity in multilayer production systems (Park and Runkle, 2017).

In summary, a deeper understanding of photoreceptor-mediated signaling and its modulation by artificial spectra is essential for tailoring light recipes that enhance growth, nutritional quality, and stress resilience in soilless crops. Hydroponic cultivation thus provides a unique opportunity to refine photobiological strategies for sustainable and efficient crop production.

2.4 Light quality and secondary metabolism in hydroponic crops

Light quality, particularly spectral composition, plays a critical role in modulating secondary metabolism in plants (Hasan et al., 2017), a set of biochemical pathways that generate compounds such as phenolics, flavonoids, alkaloids and terpenes, many of which are associated with stress tolerance, antioxidant activity and nutritional value (Böttger et al., 2018). In hydroponic systems, the high degree of environmental control offers an ideal context to fine-tune spectral inputs and thereby modulate these metabolic pathways with precision.

Blue light has been shown to influence the biosynthesis of phenolic compounds and flavonoids through the activation of key transcription factors in the phenylpropanoid pathway. This regulation is particularly relevant in leafy greens and culinary herbs, where antioxidant capacity is a core attribute of functional quality. For instance, in hydroponically cultivated japanese mint (Mentha canadensis L.), blue light significantly increased the production of monoterpenes such as menthol and menthone, indicating an upregulation of specialized metabolite pathways (Ueda et al., 2021). Similarly, kale (Brassica oleracea L. var. acephala) microgreens exposed to blue LEDs showed higher levels of phenolic compounds like quercetin and sinapic acid, accompanied by enhanced antioxidant activity (Lee et al., 2023). In basil, studies on microgreens and in vitro cultures confirmed that blue light elevates levels of rosmarinic acid and total phenolics, thus enhancing its nutritional profile (Nazir et al., 2020).

Red light, while primarily promoting photosynthesis and biomass accumulation, generally has a limited effect on secondary metabolism compared to blue or UV-A radiation (Hasan et al., 2017). However, combining red with blue light often produces synergistic effects, enhancing both vegetative growth and bioactive compound production. This has been demonstrated in crops such as sweet wormwood (Artemisia annua L.), where red-blue LEDs significantly increased flavonoid, phenolic and artemisinin content (Rai et al., 2024) and in lettuce, basil and kale, where red-blue combinations improved antioxidant properties and pigment accumulation (Trivellini et al., 2023).

Far-red light, although less efficient at directly driving photosynthesis, plays a key regulatory role in plant development through phytochrome-mediated signaling pathways, influencing growth, secondary metabolism and phenological responses (Demotes-Mainard et al., 2016). In mint (Mentha haplocalyx Briq.), supplementation with far-red light enhanced biomass accumulation and photosynthetic performance while significantly promoting the biosynthesis of phenolic compounds and flavonoids such as luteolin and methylchavicol, suggesting its utility in improving both growth and medicinal value (Yu et al., 2024). Likewise, in basil, night interruption with far-red light increased flavonoid content by over 40% and improved biomass partitioning toward leaves, contributing to enhanced quality and postharvest durability (Fallah et al., 2024). These findings are consistent with meta-analytical evidence showing that moderate far-red supplementation significantly increases plant height, leaf area and dry biomass in vegetable crops, while also modulating nutritional traits like soluble sugars (Zhang et al., 2024).

Although not part of the photosynthetically active radiation (PAR), UV-A radiation plays a pivotal role as an environmental signal, particularly as an elicitor of secondary metabolism. In lettuce, exposure to UV-A-enriched light environments has been shown to significantly enhance the accumulation of phenolic compounds and anthocyanins, along with improved antioxidant capacity, especially when applied during the pre-harvest phase (Tsormpatsidis et al., 2008).

In conclusion, spectral management in hydroponic systems offers a powerful tool to modulate the synthesis of secondary metabolites, enabling the production of high-value crops with enhanced functional properties. Understanding the specific roles of different wavebands is key to designing light recipes that balance productivity with nutritional and sensory quality.

2.5 Light as a tool for abiotic stress management in hydroponic systems

In hydroponic systems, where environmental parameters can be tightly controlled, light becomes not only a driver of photosynthesis but also a powerful modulator of stress responses. Specific light spectra can mitigate the adverse effects of abiotic stresses such as salinity, heat, drought-like conditions and nutrient imbalances (Islam et al., 2021; Soufi et al., 2023), all of which may arise even under soilless cultivation due to recirculating nutrient solutions, equipment malfunction or high evaporative demand.

Blue light has been widely associated with enhanced antioxidant defenses, primarily through the activation of genes encoding antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) (Soufi et al., 2023; Trivellini et al., 2023).

UV-A radiation can act as a priming agent, inducing mild oxidative stress that triggers acclimation responses. In controlled studies with hydroponic kale pre-harvest exposure to combined UV-A radiation and chilling stress enhanced abiotic stress tolerance by increasing phenolic compound accumulation and antioxidant enzyme activity, without compromising growth or photosynthetic capacity (Lee et al., 2019).

Red and far-red light influence phytochrome signaling pathways that regulate stomatal conductance and water-use efficiency (Legris et al., 2019). In aeroponics systems, manipulating the red:far-red ratio has been proposed as a method to reduce transpiration and improve tolerance to short-term water deficit without compromising biomass production (Carotti et al., 2023).

Furthermore, light-nutrient interactions are increasingly recognized as key to optimizing stress resilience. Under nitrogen-limited conditions, combined red and blue light improves nitrogen-use efficiency by enhancing enzymes involved in carbon-nitrogen metabolism. In tomato (Solanum lycopersicum L.) seedlings, a 3:1 red:blue ratio upregulated nitrate reductase and glutamine synthetase activity (Wang et al., 2017), while in spinach (Spinacia oleracea L.), blue-green-red light combinations boosted biomass and key nitrogen-assimilating enzymes under low nitrogen supply (Ramezani et al., 2023). In summary, beyond growth promotion, targeted light treatments serve as a non-chemical strategy to improve abiotic stress tolerance in hydroponic crops, contributing to the sustainability and resilience of soilless food production systems.

2.6 Design of lighting strategies in hydroponic systems

Designing effective lighting strategies in hydroponic systems requires an integrative approach that considers spectral quality, light intensity, photoperiod and spatial distribution (Figure 1). Unlike field or greenhouse cultivation, hydroponic systems, especially in fully controlled environments, allow for precise modulation of light parameters, offering a unique opportunity to optimize photosynthetic efficiency and plant quality.

Figure 1 Conceptual diagram summarizing plant photobiological responses to different spectral regions in hydroponic systems and their integration into lighting design strategies for optimizing growth, efficiency and stress resilience

2.6.1 Photoperiod and light intensity

Photoperiod plays a key role in plant development by interacting with circadian rhythms and flowering regulation. Most leafy vegetables and herbs respond positively to long-day photoperiods (e.g., 16 h light / 8 h dark), which promote vegetative growth and delay flowering (Adams and Langton, 2005). This response has been demonstrated in several species, including lettuce, basil and arugula (Eruca sativa L.), where a 16-hour photoperiod significantly enhanced foliar biomass and overall yield compared to shorter photoperiods.

Optimal light intensity must be defined according to crop-specific requirements and phenological stage, while ensuring energy efficiency. In general, moderate to high PPFD values (e.g., 200-300 μmol/m²/s) are often used in indoor cultivation (Pennisi et al., 2020; Gavhane et al., 2023), although the ideal range may vary. Importantly, increasing light intensity beyond a certain threshold does not always improve yield and may reduce resource-use efficiency (Engler and Krarti, 2021).

2.6.2 Directional lighting

The orientation and positioning of lighting, such as top-down, side-lighting or intercanopy lighting, can significantly impact light interception and canopy uniformity (Stamford et al., 2023). Side-lighting, for example, has been shown to enhance leaf expansion and uniformity in multilayer systems, particularly when green light is included to penetrate deeper into the canopy (Schipper et al., 2023).

2.6.3 Spectral customization

Tailoring the light spectrum according to crop species or development stage is becoming increasingly viable with programmable LED systems. For example, seedling stages may benefit from blue enriched light to promote compact growth (Treder et al., 2016), while reproductive stages may require red and far-red components to stimulate flowering (Bojka, 2020). The ability to shift spectral profiles over time allows for fine-tuned control of morphogenesis, metabolism and yield.

In summary, lighting strategy design in hydroponics should go beyond simple illumination and incorporate principles of photobiology, precision agriculture and crop-specific requirements. Thoughtfully designed lighting schemes can enhance both productivity and sustainability in soilless cultivation systems.

3 Agronomic Applications and Case Studies

The application of photobiological principles in hydroponic systems has led to significant advancements in crop performance, particularly for leafy vegetables and herbs. Controlled lighting environments offer the opportunity to optimize plant morphology, nutrient composition and productivity through spectral tuning and light management strategies.

3.1 Light source technologies and their agronomic implications

In hydroponic systems, artificial light sources determine both the quantity and quality of photosynthetically active radiation (PAR), influencing plant morphology, metabolism, and resource-use efficiency. Among the commonly used technologies-light-emitting diodes (LEDs), high-pressure sodium (HPS) lamps, and fluorescent lamps-each differs in spectral characteristics, energy performance, and suitability for various growth stages (Table 1).

Table 1 Comparative overview of artificial light sources used in hydroponic crop production

LEDs have become the preferred option for hydroponic cultivation owing to their precise spectral tunability, high photon efficacy and long operational lifespan (50,000-100,000 h). Their ability to finely adjust red and blue light ratios optimizes photosynthesis and enhances the biosynthesis of bioactive compounds, such as phenolics and flavonoids, thereby improving both yield and nutritional quality. In addition, the reduced infrared emissions of LEDs lower canopy temperatures and water demand compared with high-pressure sodium (HPS) systems, contributing to higher overall resource-use efficiency (Dannehl et al., 2021; Knyazeva et al., 2024).

By contrast, HPS lamps emit primarily within the yellow–green spectral region, which is suboptimal for photosynthetic performance. Their high thermal output increases transpiration and water stress in plants, while their relatively short lifespan (10,000-20,000 h) and declining efficiency over time limit their long-term viability for intensive hydroponic production (Dannehl et al., 2021).

Fluorescent lamps, although affordable and characterized by low heat emission, provide limited spectral flexibility and insufficient intensity for full-cycle crop cultivation. Consequently, their use is generally restricted to propagation and early growth stages rather than large-scale or commercial applications (Seiler et al., 2017; Stamford et al., 2023).

In a word, LEDs are emerging as the standard in hydroponic lighting due to resource efficiency and crop-quality enhancements. HPS and fluorescents retain niche uses in propagation or legacy systems but are increasingly being phased out.

3.2 Crop specific responses

Multiple hydroponic studies demonstrate that lighting quality and strategy significantly influence both plant productivity and nutritional composition. In lettuce, comparative experiments under LED versus HPS lighting revealed 15% reduced water consumption under LEDs without compromising yield. Notably, LED treatments increased key phenolic compounds and overall phenolic content compared to HPS (Dannehl et al., 2021). Further, dynamic red and blue LED regimens in lettuce boosted xanthophyll accumulation and enhanced photosynthetic indices and transpiration efficiency (Samuolienė et al., 2021).

In basil, the use of LED lighting has shown superior performance compared to fluorescent tubes. In a study testing four LED spectral profiles, including combinations of red, far-red, blue, green and UV, both cultivars displayed significantly greater total biomass and phenolic content under LED treatments, compared to fluorescent control (Bantis et al., 2016). A more recent study found that combinational red, blue and far-red LEDs further elevated biomass and phenolic production relative to white LEDs (Rahman et al., 2021).

Tomato research indicates that even short LED light supplementation during night periods of red/blue/far-red spectrum can enhance yield nutritional quality (Arif et al., 2024). In cucumber (Cucumis sativus L.), nutrient film technique (NFT) trials comparing LED-only lighting with combined HPS+LED and HPS-only treatments found the highest yields and chlorophyll content under LED-only conditions. Enhanced gas exchange and PSII efficiency in LED-only compartments further supported fruit yield improvements (Gajc-Wolska et al., 2021) Additionally, cucumber seedlings grown under red/blue LEDs developed stronger root systems and higher biomass accumulation than controls.

Microgreens, due to their short growth cycle and high nutritional density, are particularly sensitive to light conditions. Both the spectral composition and intensity of artificial lighting significantly influence their morphological development, pigment accumulation and nutrient content. Optimizing parameters such as the blue:red light ratio and total photon flux density can modulate key traits including shoot elongation, biomass production and the synthesis of bioactive compounds (Zhang et al., 2020; Partap et al., 2023). In a hydroponic study, increasing the proportion of blue light from 0% to 100% consistently reduced shoot elongation in mustard (Brassica juncea L.) and kale microgreens, while simultaneously enhancing the accumulation of macro and micronutrients (Brazaitytė et al., 2021).

Collectively, these studies illustrate a consistent trend: LED lighting enhances both productivity and functional quality across a range of hydroponic crops. Crop-specific ‘lighting recipes’, including tailored red:blue ratios, supplemental periods and dynamic light profiles, enable optimization of distinct outcomes such as yield, antioxidant capacity, and nutrient accumulation. This supports the concept of precision lighting in hydroponic horticulture to meet both agronomic and nutritional goals.

3.3 Practical implications of artificial light strategies in hydroponics

The evidence reviewed across multiple hydroponic crops highlights the central role of light spectrum and intensity as modulators of both productivity and nutritional quality. LEDs (owing to their customizable spectra, energy efficiency, and minimal heat output) consistently outperform traditional lighting systems such as HPS and fluorescent lamps in both yield optimization and enhancement of phytochemical profiles. These advantages are particularly evident in leafy greens and microgreens, where short cycles allow rapid phenotypic responses to spectral adjustments.

Species-specific outcomes underline the necessity of tailored “light recipes.” For instance, lettuce benefits from moderate red:blue ratios (e.g., 3:1) for biomass and phenolic accumulation (Dannehl et al., 2021), while basil and tomato exhibit improved functional traits under red and far-red enriched environments (Bantis et al., 2016; Arif et al., 2024). Microgreens, by contrast, respond to blue-dominant spectra with reduced elongation and elevated nutrient density, although responses vary significantly between cultivars (Zhang et al., 2020).

From an agronomic perspective, these findings support a paradigm shift toward dynamic lighting strategies in commercial hydroponic systems. Implementing crop and stage specific light profiles (potentially using programmable LED arrays and sensor-integrated control) could enhance both resource use efficiency and final product quality. This precision lighting approach aligns with broader goals of sustainable intensification in controlled-environment agriculture (Stanghellini and Katzin, 2024).

4 Challenges and Future Perspectives

4.1 Technical and scientific bottlenecks

Despite rapid advances in artificial lighting, several technical and scientific constraints continue to limit the large-scale implementation of optimized spectral control in hydroponic systems. LED lighting, though markedly more efficient than conventional HPS or fluorescent systems, still entails substantial energy demands and high initial costs. The installation of LED arrays typically represents 40%-60% of the total setup cost, but payback can be achieved within 3-5 years due to reduced electricity consumption and extended lifespan (Patel, 2024).

In terms of energy performance, LEDs exhibit efficiencies of approximately 3.2-3.5 μmol/J, roughly double that of HPS systems, which range between 1.4-1.7 μmol/J (Dannehl et al., 2021). Nonetheless, lighting remains one of the most energy-intensive components in commercial hydroponic systems, accounting for 25%-35% of total operational energy use. Although integrating AI-assisted dimming strategies can reduce this demand by 15%-20%, challenges persist in balancing spectral optimization with cost-effective implementation.

Another critical limitation lies in the complexity of spectral interactions. Light quality, intensity and photoperiod interact dynamically with temperature, humidity and nutrient status, making standardization across systems difficult. Discrepancies in experimental setups and reporting metrics also hinder the establishment of universal lighting “recipes” for specific crops, thereby restricting reproducibility and scalability.

4.2 Knowledge and research gaps

At the scientific level, our understanding of how specific wavelengths regulate plant metabolism and morphogenesis remains incomplete. While red and blue spectra are well studied, the physiological mechanisms triggered by green, far-red and ultraviolet radiation require further exploration. These spectral regions often display species-dependent and context-specific effects, complicating model development for precise spectral recommendations.

Integrating omics-based research can help fill these gaps. Transcriptomic and metabolomic studies, for instance, have revealed how light quality influences the expression of transcription factors such as HY5 and MYB, which control the biosynthesis of secondary metabolites and antioxidant pathways (Wu et al., 2023; Zeng et al., 2023). However, comprehensive multi-omics models linking light perception to metabolic regulation are still scarce (Zhang et al., 2022). Developing such integrative frameworks would enable predictive spectral modeling, advancing from empirical experimentation toward mechanism-driven control.

Artificial intelligence offers a promising avenue to accelerate the development of adaptive horticultural lighting systems. Machine learning and deep learning models have been successfully applied to predict light-response patterns and optimize spectral compositions, such as red-to-blue light ratios, in order to balance plant productivity with energy efficiency (Durmus, 2020). Recent developments integrate AI with real-time sensor inputs (including chlorophyll fluorescence, canopy temperature and CO₂ exchange) to create self-regulating lighting systems that adjust spectral outputs based on plant feedback (Srinivasan et al., 2024). Despite this progress, the lack of large, standardized datasets and benchmarks remains a critical limitation to fully validate and generalize these AI-driven systems across diverse crops and cultivation environments.

4.3 Future directions and integrated solutions

The next generation of hydroponic photobiology will depend on bridging molecular knowledge, intelligent technology and sustainable management. Integrating AI-powered lighting systems with sensor networks and cloud-based analytics can enable precision control, dynamic energy savings and data-driven decision-making. The convergence of omics research, machine learning and environmental monitoring represents a new paradigm for achieving both efficiency and resilience in crop production.

At the same time, economic and policy frameworks will be crucial to ensure accessibility and scalability. Initial investments in LED infrastructure remain a key barrier, particularly for small enterprises. However, global sustainability programs are increasingly providing financial and regulatory support. The European Green Deal (European Commission, 2020) includes incentive mechanisms for energy-efficient technologies and smart agriculture, while the FAO (2022) underscores the importance of digital agriculture and artificial intelligence in enabling “green transitions” within agri-food systems. Establishing standardized certification systems for energy performance, alongside public–private partnerships, will accelerate adoption and promote long-term economic viability.

Ultimately, the sustainable evolution of hydroponic lighting requires simultaneous progress in technological innovation, fundamental research and institutional collaboration. The integration of omics-driven understanding with intelligent control and supportive policy environments will define the next frontier in achieving productive, resilient, and environmentally responsible hydroponic systems.

5 Conclusion

In hydroponic agriculture, where environmental variables can be tightly controlled, artificial lighting emerges as a central factor not only for biomass accumulation but also for shaping plant morphology, metabolism and functional quality. This review demonstrates that light quality, intensity and photoperiod interact in complex ways with plant photoreceptors and metabolic networks, influencing growth performance, nutrient composition, and stress resilience.

Red and blue light remain the fundamental drivers of photosynthesis and photomorphogenesis, yet expanding the spectrum to include green, far-red and UV-A/B wavelengths provides new opportunities for fine-tuning physiological responses. Such spectral diversification enables both yield optimization and the enhancement of bioactive compounds, essential for the development of high-quality, functional crops.

Beyond physiological optimization, the integration of omics-based research and artificial intelligence offers a path toward precision photobiology. Multi-omics studies can clarify the regulatory mechanisms underlying spectral responses, while AI-driven control systems enable adaptive and energy-efficient lighting management. Together, these advances promise to transform hydroponic systems into intelligent, self-optimizing production environments capable of real-time response to plant needs.

However, technological innovation alone will not ensure sustainability. Future progress depends on coupling scientific and digital advances with supportive economic and policy frameworks. Coordinated global efforts that integrate research, industry and governance will be essential to accelerate the adoption of energy-efficient technologies, foster equitable access and enhance the resilience of agri-food systems.

In summary, overcoming the current technological and economic barriers in hydroponic photobiology will require bridging molecular-level understanding of light signaling with intelligent control and policy frameworks. The convergence of omics-driven research, AI-based spectral management and renewable energy integration represents the next frontier in achieving efficient, resilient and sustainable hydroponic production.

Conflict of Interest Disclosure

The author affirms that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.

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