CRISPR/Cas9 genome editing has emerged as a transformative tool in plant biology, enabling precise manipulation of genes involved in stress responses. In the context of plant stress memory, where prior exposure to environmental stress enhances subsequent stress tolerance. CRISPR-based approaches offer a powerful means to dissect and engineer underlying regulatory genes. A critical factor determining the success of CRISPR/Cas9 editing is the careful design and validation of single guide RNAs (sgRNAs), which guide the Cas9 nuclease to specific genomic targets. This chapter provides a detailed, step-by-step protocol for the design, in vitro transcription, and in vitro cleavage assay to check efficiency of target-specific sgRNAs for plant genome editing applications. As a case study, we describe the design and validation of sgRNAs targeting the Arabidopsis thaliana DREB2A gene, a key transcription factor associated with drought stress memory. Emphasis is placed on strategies to maximize on-target efficiency, minimize off-target effects, and assess sgRNA functionality in vitro prior to in planta applications. This chapter serves as a practical guide for researchers aiming to functionally characterize stress memory-associated genes using CRISPR/Cas9 technology.