The player has to be ready to beat the Mummified Gargantuars at the final wave, as this is a regular level. But this level won't be a problem if the player can defeat the first one, since the lawn mowers will kill the last two ones.
Start normally with two columns of Sunflowers. Kill the first zombies with Potato Mines and Iceberg Lettuces.
Plant several columns of Peashooters, then a column of Torchwoods in front of them to double the damage for the Gargantuars. Use Wall-nut if needed.