godan verb (-mu), intransitive verb
Intransitive verb describing fruit or crops becoming ripe. Less common than 熟れる (うれる) in modern speech, but still used in some contexts.
柿が熟むまで待つ。
Wait until the persimmons ripen.
畑のトマトがよく熟んでいる。
The tomatoes in the field are nicely ripened.
More common intransitive verb for 'ripen'. 熟む is less frequent and may sound slightly literary or dialectal.
The kanji 熟 carries the meaning 'ripen, mature'. The reading うむ is native Japanese, but its exact derivation is uncertain.