Effects of the Shelf Life of Organic Seed Coating Formulations on the Physical Characteristics and Quality of Tomato and Collard Green Seeds

Abstract

In conventional agriculture, most crops are grown from seeds coated with chemicals to protect against diseases and pests, which can reduce the impact of unfavorable growing conditions. However, in organic farming systems, the use of chemically treated seeds is not permitted, potentially lowering the efficiency of organic seed utilization. Therefore, developing organic seed coating formulations can enhance the viability of organic seeds, making them comparable to conventionally grown crops. This experiment therefore aimed to study the formula of organic seed coating using a Completely Randomized Design (CRD) created with four replications for three seed coating formulations: 0.3% w/v gum arabic, 0.2% w/v sodium alginate, and 0.1% w/v xanthan gum. These formulations were stored under two different conditions: controlled conditions (4 °C) and ambient conditions (27±2 °C). The coating formula was stored for 12 months and their physical characteristics were tested every three months over a 12-month period. Additionally, the formulations were tested on tomato and collard green seeds. The result indicated that the pH of all three formulations was initially highly alkaline but gradually decreased over the storage period. All formulations maintained suitable viscosity for seed coating throughout the storage period under both conditions. 0.3% w/v gum arabic film maintained 100% water solubility throughout storage, while 0.2% w/v sodium alginate and 0.1% w/v xanthan gum films showed good water solubility for the three months, which decreased over time. 0.2% w/v sodium alginate demonstrated formulation the highest radicle emergence and germination percentages for both tomato and collard green seeds compared to other formulations. Therefore, organic seed coating prepared with 0.2% w/v sodium alginate stored in controlled conditions for 12 months is recommended as an effective organic seed costing for coating tomato and kale seeds.