User blog comment:Milesprower2/My Terror from Tomorrow guide/@comment-4077536-20140418104529

For non-Prime levels I use Twin Sunflower, Iceberg Lettuce, Potato-Mine, Magnifying Grass (although I rarely use it), Cherry Bomb, E.M.Peach and Winter Melon. It hasn't failed me yet, and this strategy works with just 1 Plant Food at the start.

For Prime levels (ugh) I use Twins, Iceberg Lettuce, E.M.Peach, Winter Melons, Melon-Pults, Cherry Bomb (in earlier levels Spikerock instead) and Magnifying Grass, but it's not really reliable for 4-flag levels. I also found that it doesn't mather if you plant up to 3 columns of Melons, as it won't kill the Gargantuars quickly. When it comes to Primes, it's stalling, stalling, stalling.

Also, did you know that E.M.Peach and Iceberg Lettuce PF stack up? I've found that helpful.