Sol Invictus

Sol Invictus is an achievement only obtainable in the mobile version. This is a strategy from My How to Diary

Plants

 * Lily Pad
 * Repeater
 * Torchwood
 * Magnet-shroom
 * Coffee Bean
 * Garlic
 * Tall Nut
 * Tangle Kelp
 * Squash

Main Strategy
In the right is the initial arrangement of the plants. Note that you still have 1350 suns to spare. However, 2,000 sun are required when the fifth flag finished not every end of a flag. You get 250 suns after each flag. The consecutive Garlics are for the Pole Vaulting Zombies. This will keep them away from eating your Magnet-shrooms which are very important by the way. Keep the Tall Nuts away as possible from the last row so that they would be destroyed immediately. Just replace the Garlics when eaten. As you continue and gain more sun, add two other Repeaters and two Magnet-shrooms. The final arrangement of plants is shown below. You can use the Tangle Kelp and Squash for emergency.