In a recent study published in BiocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More, researchers Sirjana Adhikari, Michael Vernon, Scott Adams, Lawerence Webb, and Wendy Timms explored optimal growth media for sustainable basil cultivation. Their innovative approach utilized Internet of Things (IoT)-enabled smart growth cabinets for continuous physicochemical monitoring of basil growth, comparing various soilless media to traditional potting mix.

Traditional farming faces challenges like soil degradation and inefficient water usage, making soilless growth media a promising alternative for enhancing crop productivity and minimizing environmental impact. Biochar, a porous carbon structure containing over 60% stable carbon, can significantly improve plant growth by retaining nutrients, enhancing water holding capacityWater holding capacity is the amount of water that soil can retain. Biochar can significantly increase the water holding capacity of soil, improving its ability to withstand drought conditions and support plant growth.   More, and improving airspace in the growth media. This study specifically investigated how different combinations of sand, coir, and biochar (both unsoaked and nutrient-enriched), along with sand, coir, and perlite, performed against a potting mix control with 10% and 20% biochar incorporation.

Over a 30-day period under controlled conditions, the team analyzed pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More, electrical conductivity (EC), and cation exchange capacity (CEC) of the growth mixes before and after the experiment. Key growth metrics such as root length, shoot length, leaf number, fresh and dry plant weight, and leaf area index (LAI) were also assessed.

The findings indicated that incorporating 10% to 20% biochar into potting mix optimally enhanced basil growth. This resulted in significant improvements in root development and the LAI of the plants. Notably, biochar soaked in a nutrient solution demonstrated a three-fold increase in plant weight compared to unsoaked biochar, highlighting its potential as a slow-release nutrient matrix. For instance, the fresh weight of plants grown in SCB10%s (sand, coir, 10% soaked biochar) was 2.6±2.7g, while plants in SCB10%us (sand, coir, 10% unsoaked biochar) weighed only 0.9±0.8g. The study also found that replacing 10% to 20% of potting mix with biochar significantly increased the exchangeable potassium content by more than double, and for 20% replacement, by more than three times. Root length, a critical indicator of plant health, increased from 253±25 mm in the control potting mix to 305±21 mm with 20% biochar addition (PMB20%). The optimal conditions for basil growth were observed around a pH of 7.5 and an EC up to 1200 µS cm−1. While potting mix showed the best overall growth with a 13.59% daily growth rate, the 20% biochar blend achieved a comparable 11.12% daily growth rate, suggesting it can replace a significant portion of traditional potting mix without negatively impacting growth.

Despite biochar’s high exchangeable potassium and sodium, calcium and magnesium remained dominant in the potting mix, indicating the need to optimize biochar use based on the specific plant type. The negative growth rates observed in sand-based media (SCB10%un, SCB10%s, SCP) were attributed to over-watering due to sand’s high water retention, which was exacerbated by the small quantities of biochar in these mixes.

Beyond growth benefits, incorporating 10% biochar into potting mix also supports circular economy goals by enhancing plant growth and sequestering carbon. Biochar’s stable carbon structure (over 75% carbon) makes it a more durable growing medium than potting mix, which decomposes rapidly and releases greenhouse gases. This research provides timely insights into sustainable horticulture practices, emphasizing the importance of continuous IoT monitoring for real-time plant growth assessment and data-driven decision-making.

Source: Adhikari, S., Vernon, M., Adams, S., Webb, L., & Timms, W. (2025). Optimizing sustainable basil cultivation with smart-monitoring: a comparative study of biochar and soilless growth media. Biochar, 7(1), 89.