Conveyor-belt levels

Conveyor-Belt Levels are levels where all the seed packets you receive come on a Conveyor Belt, with no cost in Sun. For this reason, you never receive Sunflowers or Sun-shrooms on these levels as the seed packets do not need to cost any sun. For some reason, these are probably the easiest levels in the game because of its an amazing spawn of plants.

Levels
The final levels of the stages in Adventure Mode (Day, Pool, Fog, etc) (e.g. 1-10, 2-10, etc.) are Conveyor-Belt Levels, as well as the fifth level of every stage, except level 2-5, which is Whack a Zombie, and level 4-5, which is a Vasebreaker level (these are puzzles).

Also, the Mini-games Wall-nut Bowling, Invisighoul, Big Trouble Little Zombie, Portal Combat, Column Like You See 'Em, Wall-nut Bowling 2, and Dr. Zomboss's Revenge are Conveyor-Belt Levels.

It's Raining Seeds and Slot Machine are not Conveyor-Belt Levels, although they have very similar structures.

Strategy
Your strategy should differ slightly, depending on the level, but you should generally plant as many offensive plants as possible as soon as they are obtained, to free up room on the conveyor belt. However, save instant-use or situational plants, such as the Blover or Cherry Bomb, for when you need to use them. Also, remember to plant at the back of the Lawn if you have enough range, as you don't need room for sun-producing plants.

Trivia
thumb|300px|left|"Ultimate Battle", the theme that plays on most of the conveyor-belt levels
 * Sunflowers, Sun-shrooms, Garlics, Umbrella Leaves, Marigolds, and Planterns never come on Conveyor-Belt Levels, although Marigolds, Garlics, and Planterns can fall from the sky.
 * You never receive Upgrade Plants or the Imitater, most likely because it wouldn't make sense to have them if you hadn't decided to purchase them yet.
 * The music heard in ?-5 Conveyor-belt Levels is "Loonboon" (excluding Level 4-5 which plays "Cerebrawl" because it is a Vasebreaker Level), while the music played in the ?-10 levels is "Ultimate Battle" (excluding Level 5-10 which plays "Brainiac Maniac" as it features Dr. Zomboss and Level 4-10 in which no music plays at all).
 * Before level 2-10, you get a note says zombies attacking for "midnight snack", but it is actually takes place at dawn, if for the fact that all the Night levels take place in one night. Though it's also possible that each Night level takes place in a different night.
 * In IPod Touch version, the belt is on the side with the plants scrolling upward.
 * For the original concept, the conveyor belt is used to randomly load plants on each level instead of clicking and dragging your plants on the screen.
 * When playing the final level of a stage, you'll only recieve plants obtained in this stage (except the Lily Pad in 4-10 and Jalapeno, Ice-shroom in 5-10).
 * Zombies call the 1-10 level an all-out attack. While they pretend they are the player's mother before 4-10.
 * In the IPod Touch version Ultimate Battle doesn't play on the 1-10 (and 2-10 and 3-10). Instead it plays the level's regular theme.