Push to array of subdocuments only when no other subdocument in that array matches multiple conditions?

I’m making a 2D grid based farming sim type game, where each grid cell can only allow one plant to occupy it at once.
I am storing these plants for the user as an array of subdocuments, where each one details the type and position of the plant.

  { _id },
    $push: {
      plants: {
        type: somePlantTypeValue
        row: someRowValue,
        col: someColValue,

What am I looking for to figure out how I can add a condition to ensure that there is no existing entry in plants that already has the same row and col as the subdoc to be added, to prevent two plants from being stored on the same tile?