Left component —
青 is both the indexing radical and the phonetic (qīng → jìng with initial palatalization).
青 names the green-blue of growing plants and clear sky, carrying a 'pure/clear' flavour that fits
静's calm meaning directly. As a phonetic it also drives
清 (clear water),
情 (feeling),
请 (please) — a tight qing/jing family.