Trim, wash, chop — not a single step can be skipped.
Tips
usage
择 has two readings: literary 'zé' (to choose, as in 选择) and colloquial 'zhái' when used for sorting food — CC-CEDICT gives 择菜 as zhái cài. It's the prep step before washing: picking off wilted leaves, peeling tough stems, snapping off roots.