Design and Implementation of a Low-Cost Controlled-Environment Growth Chamber for Vegetative Propagation of Mother Plants

Abstract

This Technical Note presents the design and implementation of a low-cost modular growth chamber developed to keep mother plants under controlled environmental conditions for vegetative propagation. The system was conceived as an accessible alternative to expensive commercial equipment, offering reproducibility and adaptability for small-scale and research-based cultivation. The proposed chamber integrates thermal insulation, LED lighting, forced ventilation through the implementation of extractors, a recirculating irrigation system with double filtration, and a sensor-based environmental monitoring platform operated via an Arduino UNO microcontroller. The design features a removable tray that serves as a support for the mother plant, an observation window covered by a movable dark acrylic that prevents the passage of external light, and a vertical structure that facilitates optimal space utilization and ergonomic access. Functionality was conducted using a Stevia rebaudiana Bertoni mother plant maintained for 30 days under monitored conditions. Environmental parameters—temperature, relative humidity, and illuminance—were recorded continuously. The plant showed vegetative development through new shoot emergence and the growth in height of the plant, and despite a loss in foliage expansion, it confirmed the chamber’s capacity to support sustained growth. Although no statistical replication or control group was included in this preliminary evaluation, the system demonstrates technical feasibility and practical utility. This chamber provides a replicable platform for future experimentation and propagation studies. Complete technical specifications, schematics, and component lists are provided to enable replication and further development by other researchers. The growth chamber design aligns with the goals of open-source agricultural innovation and supports knowledge transfer in controlled-environment plant propagation technologies.

1. Introduction

Agriculture is a vital sector of the global economy and a cornerstone of food security. However, the sector faces major challenges associated with climate change, environmental degradation, and resource scarcity. According to the Food and Agriculture Organization of the United Nations (FAO), agricultural activities contributed approximately 12% of global greenhouse gas emissions in 2020 [1]. Meanwhile, primary crop production continues to grow, reaching 9.9 billion tons in 2023, yet food insecurity remains a pressing issue, affecting over 700 million people worldwide due to population growth over time [2,3]. This paradox reflects the growing demand for food production alongside the diminishing availability of fertile land, water resources, and agricultural labor [4]. As a result, the adoption of sustainable practices and advanced technologies has become imperative for the future of agriculture [5,6].

One promising approach involves the vegetative propagation of mother plants through asexual reproduction. This method allows for the preservation of desirable genotypes and ensures uniformity in plant production, a key requirement for modern protected agriculture systems [7]. Controlled-environment agriculture (CEA), which includes technologies such as greenhouses and growth chambers, enables crops to be cultivated year-round, under optimal conditions for temperature, humidity, light, and nutrient supply [8,9]. These systems offer increased productivity, reduced pest incidence, and more efficient use of water and nutrients. Moreover, they facilitate the conservation and propagation of endangered plant species by maintaining genetic fidelity through clonal propagation [10,11]. In this context, a single mother plant is typically sufficient to produce large numbers of cuttings while maintaining genotype purity, making it both biologically and operationally efficient to design chambers around individual specimens.

Despite these advantages, the implementation of CEA technologies, particularly growth chambers, is often limited by high construction and operating costs, along with the need for continuous monitoring and maintenance, in which farmers and horticulturists require constant training. Commercial chambers typically lack flexibility and are tailored to the specific needs of small-scale propagation systems, making them economically unviable for researchers, educators, or growers with limited resources [6,12]. In this context, there is a critical need for accessible and customizable alternatives.

This Technical Note presents the design, implementation of a low-cost, modular vegetative growth chamber (VGC), intended for maintaining mother plants in the vegetative phase under controlled environmental conditions in order to bring them to a maturity phase that can obtain cuttings. The chamber integrates multiple systems—including temperature and humidity sensors, adjustable LED lighting, a ventilation system that allows internal air circulation and a recirculating irrigation circuit with dual filtration that generates savings in water resources, automated through an Arduino UNO microcontroller. The structural design includes a removable tray in which the mother plant container is placed for easy access, an observation window covered with a dark acrylic that prevents natural light from entering, and an ergonomic vertical layout designed for indoor or small-space environments.

The VGC was assessed using a Stevia rebaudiana Bertoni mother plant kept inside the chamber for a period of 30 days. Stevia is a species of growing economic and medicinal interest, known for its sweetening properties and bioactive compounds. It requires specific environmental conditions for successful vegetative propagation, making it a suitable candidate for evaluating the chamber’s capacity to sustain growth, as in this way, such conditions can be replicated in the VGC and the chamber’s functionality can be verified [13].

Although the system was tested using a single plant and without an external control group—consistent with the scope of this early-stage technical deployment—the chamber demonstrated its capacity to maintain stable environmental conditions conducive to the shoot, including development of new shoots and growth in height, although the loss of foliage expansion was reflected. This work represents a technological contribution towards affordable and replicable growth chamber solutions in CEA research and plant propagation initiatives. Full technical specifications and design documentation are provided to support adoption, adaptation, and further development by the scientific community.

2. Materials and Methods

2.1. Patent Review of Related Technologies

To identify the current state of technological solutions for controlled-environment plant systems, a review of recent patents was conducted. Patent US20,220,039,335 [14] describes a grow tent with a hexagonal reflective structure and adjustable height by telescopic poles, incorporating ventilation flaps and modular closures. Patent ES1,073,388 [15] presents a rigid, compartmentalized grow cabinet with dedicated chamber for flowering, germination, and drying each with airtight seals and independent lighting. Similarly, Patent ES1,075,954 [16] features a wall cabinet with stepped trays and a gravity-fed irrigation system. Finally, Patent WO2,021,224,519 [17] proposes a modular and foldable hydroponic unit with nutrient tanks and automated irrigation.

KOMEG are manufacturers of climatic chambers. For 30 years, they have carried out the construction of such chambers in which they seek constant innovation. The products offered by KOMEG (Dongguan, China) are based on temperature and humidity test chambers, environmental chambers, thermal shock chambers, battery test chambers; however, despite being able to use these chambers in different areas, they are not specific for plant cultivation. However, they can be adapted; an example is the environmental chamber [18].

Garden HighPro is a supplier of accessories for crops, as well as grow tents, each with similar designs. However, only the dimensions change, using, in each one, 420D Nylon fabrics; these are patented structures that offer a premium mylar reflection of 97%. The internal coating is the material that helps with reflection. It has air vents on the sides and a closing and an opening, and a window that lifts up in order to cover when necessary [19].

Although innovative, these designs do not prioritize environmental control for mother plant cultivation. Most target seedling or cuttings production and lack integrated climate monitoring; the systems implemented in the patents show the structure of the design without further mentioning functionality. Our proposed Vegetative Growth Chamber (VGC) addresses this gap by providing an environment designed specifically for sustained mother plant maintenance, with full environmental control and resource reuse.

The design of the VGC incorporates an efficient irrigation system that allows the recirculation of the water resource, optimizing its use and minimizing waste. Additionally, the VGC has a removable tray where the plant is placed, facilitating its access for the collection of pruning and cutting without affecting its development. This feature allows for more efficient crop management and maximizes the use of internal space. In addition to maintaining the environmental control systems that allow the replication of the specific environmental conditions for each plant, the programming allows real-time monitoring of the VGC. This ensures stability in key environmental factors for healthy mother plant growth and efficient propagation.

2.2. Design and Construction of the Vegetative Growth Chamber (VGC)

The VGC was designed and assembled at the Laboratory of Inventions Applied to Industry (LIAI) of the Autonomous University of Zacatecas (UAZ), Mexico. The camera has a rectangular prism morphology with external dimensions of 90 cm (width) × 150 cm (height) × 80 cm (depth). It is divided into two sections:

• Upper section: Reserved for the plant and vertical development of the foliage (90 cm in height).
• Lower section: Houses the irrigation reservoirs and supports root expansion of the root through a system of suspended trays (60 cm stainless steel mesh).

The chamber was specifically designed to house a single mother plant. From a biological and operational standpoint, one elite mother plant is sufficient to generate a high number of genetically identical cuttings. Although many propagation systems can support multiple plants simultaneously, this prototype was intentionally configured for a single-plant layout to facilitate precise environmental control, minimize spatial interference, and simplify data collection and monitoring. This design choice ensures structural simplicity and is fully aligned with the propagation purpose of the system.

The frame was built with rigid wood panels for thermal insulation and lined internally with expanded polystyrene (EPS) to stabilize humidity and temperature. Assembly employed adhesives, screws, and anchors for structural integrity.

The front panel incorporates a door with a locking mechanism and observation window for non-intrusive monitoring. A removable tray (Figure 1, Element 2) was installed on side rails, facilitating access for pruning and harvesting. The mother plant container (Element 3) is a tubular mesh-supported vessel allowing optimal root development, compatible with hydroponic or aeroponic systems.

Figure 1 shows the computer-aided design (CAD) of the growth chamber and the layout of key components designed in SolidWorks version 2023 software.

The irrigation system includes three PVC reservoirs constructed from 8-inch diameter pipes:

• Reservoir 1 (Element 4): Stores clean, aggregated irrigation solution to start the irrigation cycle.
• Reservoir 2 (Element 5): Receives the used solution, filtered through Filter 1 (Element 7), mesh, and fabric filter that prevents the passage of impurities.
• Reservoir 3: Receives additional filtering via Filter 2 (Element 8), smaller filters that are used to clean the rest of the solution prior to recirculation.

Inside, a removable tray was installed (Element 2, see Figure 1) with front supports and side rails to facilitate movement, where the containment of the mother plant is located that facilitates the pruning and entry of the plant. The mother plant container (Element 3, see Figure 1) has an 8-inch PVC tubular structure that features mesh in its midsection to support and facilitate root growth. The implemented design is compatible with cultivation techniques such as hydroponics and aeroponics, optimizing the growth and development of plants.

For the lighting, an LED light strip (Element 16) was placed on top of the VGC. For air circulation, extractors (Elements 12) were placed to allow air to enter and exit.

A schematic overview of the integrated systems is presented in Figure 2.

The irrigation system flows by gravity, and double water pumps (Elements 9 and 10) powered by a 12 V supply ensure redistribution. The entire system forms a closed-loop irrigation cycle.

The ventilation system maintains air circulation inside with the implementation of air extractors, which allows us to modify the temperature and humidity, in addition to preventing the accumulation of bad odors; however, it does not have filters.

The lighting is provided by an LED light strip (Element 16) which can be connected via Bluetooth USB, with RGB pixel light controller maintaining a maximum power of 2048 pixels.

Photographic views of the fully constructed chamber are shown in Figure 3.

In the assembly, the internal cladding panels were assembled with expanded polystyrene (EPS), a material that improves thermal insulation to maintain internal climatic conditions such as temperature and humidity. At the bottom of the chamber and at the top of the removable tray, it has the adhesion of gridded vinyl, where each frame measures 1 cm, which helps with the measurement of plant growth.

2.3. Environmental Monitoring and Automation System

Environmental variables are regulated through an integrated system consisting of the following:

• Lighting: Full-spectrum LED strip with RGB pixel light controller maintaining a maxi-mum power of 2048 pixels affixed inside the upper chamber. Controlled via relays triggered by light sensors, ensuring a photoperiod of 8 h on, 8 h off.
• Ventilation: Two exhaust fans activated via relay modules based on temperature and humidity thresholds.
• Sensors: A DHT22 sensor monitors ambient temperature and humidity with ±0.5 °C and ±2–5% accuracy, respectively.
• Lighting sensor: A photoresistor detects light intensity (2–5 k lumens range) for LED control.
• Controller: An Arduino UNO microcontroller processes sensor input and manages actuator response.

All environmental data was logged in real time to evaluate system stability during operation the growth chamber functional assessment (VGC).

2.4. Experimental Setup and Operation Protocol

A single Stevia rebaudiana Bertoni mother plant was cultivated inside the VGC over a 30-day period (November 1–30). Prior to installation, the plant was acclimated under outdoor conditions to reduce transplant shock. Once inside, environmental parameters were continuously monitored.

For this functional demonstration of the VGC’s environmental control system, the Stevia rebaudiana Bertoni mother plant was maintained without a specific substrate, akin to its natural growing conditions. This allowed for direct assessment of the chamber’s ability to provide stable environmental parameters. While initial tests with alternative substrates encountered issues like fungal growth, future research will focus on optimizing cultivation protocols, including the selection of suitable substrates (e.g., coconut fiber, rock wool, perlite, or nutrient solutions), to ensure optimal plant health and propagation success.

Stevia rebaudiana Bertoni is a shrub that can reach up to 0.9 m in height, with glossy dark green leaves and rough texture. For optimal development, it requires mild temperatures between 15 and 38 °C, high relative humidity (approximately 85%), and prolonged exposure to solar radiation; however, excessive sun exposure can cause dehydration and affect the plant’s rooting process [20].

In the cultivation of Stevia rebaudiana Bertoni, light is a key environmental factor, which influences its morphological development, since the spectrum, intensity, and duration of light allows plant growth to be optimized. Stevia is a plant that requires light for a short time, which means that it naturally flowers when the days are shorter, requiring a period of light of less than 13 h of light in such a way that the light is divided into 2 sections of 8 h each [21].

• Temperature: 20–30 °C, regulated by fan activation.
• Relative humidity: 30–60%, modulated by airflow circulation.
• Lighting: 8 h photoperiod, via LED system.
• Irrigation: Tap water was used for preliminary functionality assessment (future tests will apply nutrient solutions).

Figure 4 provides photographic documentation of the installation process of the mother plant inside the chamber, from selection to final positioning.

2.5. Materials and Construction Techniques

The structural body of the chamber was built using the following:

• Wooden frame: Renewable and thermally stable, as well as providing a stable rigidity for the support of the structure [22].
• EPS insulation: Improves thermal retention, maintaining conditions for a long time [23].
• PVC reservoirs: Joined using specialized PVC adhesives and drilled to interface with hose and pump connectors during irrigation.
• Sprinklers: 180° mist nozzles for efficient irrigation distribution.

All systems were assembled and integrated manually. Pumps, sensors, relays, and lighting modules were calibrated and connected using soldered terminals and secured cable paths. The control logic was programmed in the Arduino IDE and loaded into the microcontroller for autonomous operation, connected to a monitor where the data of the variables were obtained during the evaluation of the VGC.

2.6. Monitoring and Growth Metrics

During the 30-day test period, the mother plant was assessed for the following:

• Environmental stability: Real-time logging of temperature, humidity, and light levels.
• Growth indicators: Height and foliage diameter, recorded on day 1 and day 30 using a flexometer.
• Checkered vinyl: Each frame of the vinyl measures 1 cm which provided information for the measurements of the growth of the plant, in addition to the use of the flexometer.

3. Results

3.1. Environmental Conditions Inside the Chamber

During the period of operation, the internal environmental conditions of the Vegetative Growth Chamber (VGC) were continuously monitored over 30 days, with data recorded every second using calibrated digital sensors. The system measured three key parameters: internal temperature (°C), internal relative humidity (%), and internal illumination (lumens).

Due to the high density of data points (approximately 2.5 million records), only a representative 7-day period—from 21–27 November 2024—was selected for graphical analysis to enhance visual clarity. However, a statistical summary of the entire 30-day dataset is provided in

Table 1. Environmental parameters summary (30 Days).

Parameter	Minimum	Maximum	Average
Temperature (°C)	25.5	29.1	28.8
Relative Humidity (%)	25.1	41.7	35.62
Illumination (lumens)	57.5	137.5	70.42

, including the minimum, maximum, and average values for each parameter monitored during the experiment.

These values helped identify trends and fluctuations in each parameter. Temperature and relative humidity showed stability in their extreme values. The internal temperature remained within a functional range for vegetative development, showing minimal fluctuations. Relative humidity showed moderate variability, likely influenced by both irrigation cycles and ventilation control. Illumination followed a consistent 8 h photoperiod, reflecting the programmed operation of the full-spectrum LED lighting system.

The 7-day graphical representations of temperature, humidity, and illumination are shown in Figure 5, Figure 6 and Figure 7, respectively. These visualizations illustrate diurnal environmental dynamics inside the VGC and reflect the effectiveness of the integrated control systems.

As shown in Figure 6, the nighttime increase in humidity between 23:00 and 00:00 corresponds to the irrigation cycle, followed by a decrease due to programmed ventilation activation. This fluctuation is consistent with the control logic of the system. While acceptable for a functional prototype, future improvements will aim to reduce such oscillations to ensure a more stable microclimate.

During the monitoring of the 30 days, it took 7 days to see the values obtained for temperature, humidity, and lighting, in which a constant pattern in temperature was observed between 28 and 30°, the air extractors allowed to regulate the internal thermal conditions between 25 and 27 °C. Humidity began at 60%, but as it was monitored it stabilized at values between 30 and 45%, influencing irrigation and ventilation. The LED lighting follows a constant cycle of 8 h on for plant growth, with slight adjustments between days to optimize plant growth.

3.2. Visual Assessment of Plant Development

Throughout the 30-day assessment period, the mother plant Stevia rebaudiana Bertoni was observed under controlled conditions within the VGC by capturing images with cameras fixed at key locations, one at the front of the plant and one taking snapshots at the top. Visual monitoring focused on key morphological indicators such as apical growth, shoot development, and leaf expansion. The plant exhibited healthy vegetative behavior consistent with propagation readiness.

During the first week, the plant acclimated to the chamber environment with no signs of stress. By the second week, multiple new shoots were visible and foliar density increased noticeably. By the end of the evaluation, the foliage showed full horizontal expansion and vibrant coloration, confirming the system’s suitability for maintaining the growth of a mother plant in the vegetative phase.

These observations are illustrated in Figure 8a–d, which shows the plant at key stages of development: before installation, during the first week, mid-cycle, and on the final day of the test.

During the experiment, precise measurements of the mother plant were taken using a flexometer to record both initial and final measurements. These included maximum and minimum height and foliage diameter, measured manually with initial and final readings taken during the experimental phase, as shown in

Table 2. Manual growth recording of the mother plant.

Plant	Maximum Height (cm)		Minimum Height (cm)		Diameter (cm)
Stevia rebaudiana Bertoni	Initial	Final	Initial	Final	Initial	Final
	32	43	11	17	14 × 16	19 × 21

. Height measurements allowed for evaluating vertical growth, while foliage diameter reflected lateral expansion and development; these were crucial data for analyzing the impact of controlled environmental conditions in the growth chamber. Table 2 shows the recorded changes in plant height and diameter during the experiment.

From the beginning of monitoring, significant changes in the plant’s height and foliage were documented and manually recorded during this monitoring period. During the monitoring process, a reduction in the number of leaves was observed in the lower part of the stem, some of which acquired a different tone before falling. However, new shoot growth was observed both at the base and upper part of the stem. Throughout the 30 days, stem growth was constant, reflecting vigorous development in terms of height.

4. Discussion

The Vegetative Growth Chamber (VGC) developed in this study successfully maintained stable environmental conditions for a mother plant over a 30 day period, the temperature, humidity, and light levels observed were within the expected physiological ranges for Stevia rebaudiana Bertoni during its vegetative phase These results validate the technical ability of the system to support plant health under controlled conditions, using low-cost components and a modular structure, the chamber effectively reproduced the environmental consistency often reserved for high-end systems, with minimal fluctuations and programmable settings.

A critical design decision was the allocation of space and environmental regulation for a single mother plant, this choice was intentional and based on propagation logic. In vegetative cloning, the focus is on preserving and multiplying a specific genotype, which does not require more than one donor plant [24]. Adding more plants would introduce spatial limitations, potential variability, and a loss of environmental precision; in addition, maintaining one plant facilitates maintenance, monitoring, and the uniform distribution of light and airflow, and savings in resources such as the irrigation solution, which are key aspects for a constant vegetative output.

Beyond technical validation, the economic feasibility of the VGC is central to its relevance, one of the primary limitations for research institutions and small-scale growers is the high cost of commercial climate-controlled chambers, as shown in

Table 3. Economic comparison of growth systems.

System	Estimated Cost (USD)	Key Features
Garden HighPro (Madrid, Spain) Clone Tent (80 × 60 × 40 cm)	65.0	Reflective interior, passive ventilation, low-cost tent
VGC Prototype (this work)	210.0	Custom LED, humidity and temp sensors, low-cost build
SuperCloner50-Site System	249.9 5	50-site hydroponic cloning, compact size
MSE PRO Plant Growth Chamber (250 L)	7281.95	LED lighting, humidity and temperature control, research grade
WatchDog 2475 3686WD (Spectrum Technologies, Bridgend, UK)	24,748.4	Full climate control, CO2 injection, data logging, industrial-scale

, many market-available systems exceed several thousand dollars in cost, with prices ranging from $249 to over $24,000 USD, depending on complexity, capacity, and manufacturer. In contrast, the VGC presented here is fabricated with locally available materials and open-source electronic components, achieving functional performance at a total estimated cost below $250 USD, positioning the design as an accessible alternative for experimentation and small-scale plant propagation.

A detailed breakdown of the VGC’s construction costs is provided in Appendix A.

From the resulting costs shown in Table 3, the difference between the existing products and the VGC prototype is observed, in which the Garden HighPro has a low cost of 65 USD; however it is a prototype with a reflective interior and passive ventilation, defining it as a tent [25]. The prototype of this work has a cost of approximately 210 USD, based on the cost of the current components that make up the prototype, which does not include the development expenses. The SuperCloner50-SITE System has a higher cost of 549.95 USD, which is a 50-site hydroponic cloning system with a compact size [26]. The prototype MSE PRO Plant Growht Chamber (250L) offers LED lighting, humidity control, temperature, and presents a research grade; however, its cost tends to be higher, having a cost of 7281.95 USD [27]. Finally, the WatchDog 2475 3686WD (Spectrum Technologies) offers full climate control, CO₂ injection, data logging, and having an industrial scale, so it leads to a higher cost of 24,748.4 USD [28].

The ability to replicate environmental conditions with a simple Arduino-based control system illustrates the potential to democratize agricultural technology. The modularity of the design allows for repairs and upgrades without depending on proprietary parts. For example, the lighting system can be replaced with higher-efficiency LEDs, and the irrigation loop can be extended for nutrient delivery in hydroponic applications. Future research will also focus on optimizing cultivation protocols, implementing the selection of suitable alternative substrates to which plant growth is adapted, leaving behind the natural growth conditions of Stevia rebaudiana Bertoni to ensure successful propagation, with such possibilities opening up avenues for adaptation to different species or cultivation purposes.

Despite the favorable performance, certain aspects of the design require further optimization. As noted in Figure 8d, the plant exhibited partial loss in the lower leaves during the final stage of the trial. Although this is not unusual in confined vegetative chambers, it suggests that airflow dynamics or humidity levels near the substrate. In addition to having more stable handling in temperature, future iterations could incorporate dynamic fan control or compartmentalized airflow paths to address these microclimatic variations.

Furthermore, a CAD-based redesign was developed during the evaluation process to unify and reinforce the structural components of the system, in addition to restructuring the dimensions in order to better enable its management and access to sites. As shown in Figure 9, the updated design consolidates the irrigation, lighting, and environmental monitoring components within a streamlined enclosure while allowing easy access to the plant and reservoirs. Such a design enhances functionality, user interaction, and system replicability.

In summary, the VGC fulfills its intended role as a compact, low-cost, and functional system for maintaining mother plants under controlled environmental conditions. Its simplicity, modularity, and affordability make it a candidate for adaptation and open distribution in research, education, and decentralized agriculture initiatives.

5. Conclusions

This work presented the design, fabrication, and functional of a vegetative growth chamber (VGC) developed to support the propagation of the mother plant in controlled environments was presented. The system was operational within a period of 30 days with continuous environmental monitoring and automated irrigation management. The prototype maintained temperature, humidity, and lighting within the functional ranges for vegetative development, supporting sustained shoot growth and height elongation. Even though the plant did not reach maturity for cutting extraction within the trial period, it showed continuous vegetative activity and morphological indicators of health and adaptation.

The chamber integrated critical components such as a suspended root tray, a recirculating irrigation system with dual filtration, air extractors, full-spectrum lighting, and programmable sensors, the setup enabled a stable root-zone moisture regime and minimized environmental variability. The irrigation system demonstrated efficiency in resource use, while environmental sensors allowed real-time data capture and autonomous control through open-source programming.

The modular and low-cost nature of the VGC highlights its potential for adaptation and scalability in diverse contexts. As a next step, improvements to the control interface and sensor calibration are proposed to enhance environmental stability and data accuracy. Based on the results, the VGC is a promising solution for localized, reproducible plant propagation under controlled conditions, especially in resource-limited or educational settings.