Plant height and leaf area index (LAI) are crucial growth indicators that reflect the growth status of tomatoes in greenhouses, enabling accurate determinations to effectively estimate crop transpiration and formulate irrigation strategies for reducing agricultural water waste. There is a need for the increased application of related models to simulate tomato growth indices in the traditional greenhouse production in China. This study proposes a nondestructive, real-time monitoring and simulation device for measuring tomato plant height and leaf area index. The weight of aboveground tomatoes was obtained by suspending tomato plants on dynamometers, while the total weight of stem and leaf organs was determined using a distribution coefficient simulation model. The R² value between the measurements from the electronic scale and those from the aboveground fresh weight device for tomatoes was 0.937, with an RMSE value of 0.05 kg. The monitoring device did not affect the average tomato growth during operation. The device will not affect the growth of tomatoes during monitoring. A multiple linear regression was used to compare the measured and simulated values of the plant height and leaf area index of various types of greenhouse tomatoes cultivated in different greenhouse types. The average R² value for simulating plant height was 0.817 with an RMSE of 10.81 cm. The average R² value for the leaf area index was 0.854, with an RMSE of 0.55 m²·m⁻². The simulated values for plant height and leaf area index closely matched the measured values, indicating that the model has high accuracy and applicability in traditional Chinese greenhouses (solar greenhouses and insulated plastic greenhouses). However, further optimization is required for commercially produced, continuous plastic greenhouses equipped with greenhouse environmental control equipment.

Carbon dioxide (CO₂) is one of the important factors affecting vegetable yield in controlled environments. This study used cucumber as an experimental material to investigate the effects of hanging different amounts of CO₂ generation bags (CGBs) on the growth of temperature-loving vegetables under facility soil cultivation. CGBs of three different densities were set up: no application (TC), eight bags/265 m² (T1), and sixteen bags/265 m² (T2). The results showed the following: (1) Hanging CGBs at different densities significantly impacted indoor CO₂ concentration. Light, temperature, and humidity also affected CO₂ concentration to a certain extent. (2) The application of CGBs improved cucumber growth, photosynthesis, and quality-related indexes, resulting in a 28.9% increased yield compared to the control group. (3) The economic benefits of CGB application in each group were analyzed, revealing the economic benefits of high-density CGB cultivation on solar greenhouse cucumber. This study explored a low-cost and effective CO₂ generation application mode.