preemergent

American  

[pree-i-mur-juhnt] / ˌpri ɪˈmɜr dʒənt /

Or pre-emergent

adjective

Horticulture.

1. of or relating to seedlings before they emerge or appear above ground.

   a preemergent weed-killer.

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noun

1. a preemergence chemical, as a herbicide.

Etymology

Origin of preemergent

First recorded in 1955–60; pre- + emergent

Example Sentences

Bare patches in the lawn can be cultivated and seeded in early spring, but be aware that preemergent herbicides applied now will impede grass seed germination.

From Washington Post

In the spray was a preemergent that would carry over into spring to help with weed control.

From Time Magazine Archive