IPA: /ˈʌndərˌsoʊ/
KK: /ˈʌndərˌsoʊ/
To plant a second crop in the same area after the first crop has grown, allowing both crops to grow together.
Farmers often undersow legumes to improve soil health while the main crop is still growing.
Past: undersowed
Past Participle: undersown
Undersow is formed from "under-" (meaning beneath or below) and "sow" (from Old English "sūgan", meaning to plant seeds). The word refers to the act of planting seeds beneath existing crops or vegetation.
Think of planting seeds 'beneath' ('under-') other plants — that's what undersow means.
No commonly confused words.