Survival Mode

In Survival Mode, unlocked when Adventure Mode is beaten for the first time, you must survive multiple waves of zombies. You get to choose new seed packets to defend against a different group of zombies, five in total, every 1 or 2 flags (depending on whether playing the normal or hard versions) to continue building up your defenses. For each group of zombies, the plants you previously had on the lawn and your sun remain, but Lawn Mowers, Pool Cleaners, and Roof Cleaners are not renewed.

Normal Modes - Day through Roof
In each of these modes you must survive 5 flags of zombies, with a new group after each one. The zombie concentration is the same as in Adventure Mode levels, so these levels should be pretty easy. Zombies from other areas may show up in some cases, such as Screen Door Zombies in Survival: Day.

Hard Modes: Day (Hard) through Roof (Hard)
These levels, as the name states, are quite hard. This time, you must survive 10 flags, with the zombies changing every two flags. To win this, plants like the Twin Sunflower, Winter Melon, and Tall-nut are essential. As the groups are different every time you play a level, it is not possible to create a strategy based on exactly what was encountered. You will probably want to have your Sunflowers inside Pumpkins in the back with a row of Split Peas, Spikerocks, or a pair of Gloom-shrooms (one on the second row from the bottom, and one on the second row from the top) if Digger Zombies come, or a row of Cactus's if there are Balloon Zombies, although Cattails wok much better for this purpose in Survival: Pool (Hard and Survival: Fog (Hard) (although Blovers can also work, but you have to pay extreme attention). Survival: Day (Hard) and Survival: Pool (Hard) should be the easiest, with Survival: Roof (Hard) slightly more difficult, Survival: Night (Hard) still harder, and the hardest being Survival: Fog (Hard), though this is subjective. Cob Cannons come in handy on these levels, as there will probably be Gargantuars at some point, but they are not necessary; Cherry Bombs, Jalapenos, and Squash should be sufficient. However, they make Survival: Roof (Hard) much less strenuous, and are very useful on Survival: Fog (Hard).

Survival: Endless
This time, you attempt to survive as many waves of zombies as you can, choosing new seeds every two flags. At first, the zombie density is the same as in the Hard modes, but it quickly grows to over that of Column Like You See 'Em. Gloom-shrooms, Winter Melons, and Pumpkins are essential here, and the Cob Cannon is a must in almost all builds. Instants are very good here, although not completely necessary with the Cob Cannons, and zombies come in such droves that playing a half-hour of this will earn you maybe 20 or 30 thousand dollars if you only click half or a third of the coins, given that you are at least 10 or 15 waves in. The high number of zombies also has the effect of generating many diamonds in a short time; at its best a diamond may appear every 4-5 seconds.

One good idea is to use Cabbage-pults instead of Peashooters when starting out in order to better defend against Screen Door Zombies and Ladder Zombies. Alternatively, (depending on preference) you could use Potato Mines and Imitater Potato Mines combined with Cattails to hold the zombies back while you save up to go straight to Winter Melons, Cob Cannons, Gloom-shrooms, or other powerful plants.

For a more in-depth Survival: Endless guide, click here.