- Coloque o StringGrid no form.
- No evento OnCreate do form coloque o código abaixo:

procedure TForm1.FormCreate(Sender: TObject);
begin
  StringGrid1.RowHeights[0] := 15;
  StringGrid1.RowHeights[1] := 20;
  StringGrid1.RowHeights[2] := 50;
  StringGrid1.RowHeights[3] := 35;
end;