Conveyor-belt levels

Conveyor-Belt Levels are levels where all the Seed Packets the player receives come via conveyor-belt, with no cost in sun. For this reason, sun-producing plants are not present on conveyor-belt Levels because no sun is required. In Plants vs. Zombies 2, Brain Busters conveyor-belt levels are called Special Delivery.

Plants vs. Zombies

 * The final levels in each area in Adventure Mode (1-10, 2-10, 3-10, 4-10, 5-10).
 * Levels 1-5, 3-5, and 5-5.
 * Mini-games and Cancelled Mini-games: Wall-nut Bowling, Invisi-ghoul, Big Trouble Little Zombie, Portal Combat, Column Like You See 'Em, Wall-nut Bowling 2, BOMB All Together!, Can You Dig It?, Dark Stormy Night, Bungee Blitz and Dr. Zomboss's Revenge.

It's Raining Seeds is not a Conveyor-Belt Level, although it has a very similar structure.

Plants vs. Zombies 2

 * Ancient Egypt: Days 4, 8 and 25.
 * Pirate Seas: Days 8 and 25.
 * Wild West: Days 4, 8, 12, 20 and 25.
 * Far Future: Days 8, 16 and 25.
 * Dark Ages: Nights 4, 10, 13 and 20.
 * Big Wave Beach: Days 3, 5, 8, 10, 16, 18, 21, 26 and 32
 * Frostbite Caves: Days 3, 5, 8, 10, 16, 18, 21, 25, and 30.
 * Most Piñata Parties (with some exceptions)

Strategies
The player's strategy should differ slightly, depending on the level, but they should generally plant as many offensive plants as possible as soon as they are obtained, to free up room on the conveyor belt. However, saving instant-use or situational plants, such as the Blover or Cherry Bomb, for when it is needed is an excellent strategy. Also, the player should remember to plant at the back of the lawn if they have enough range, as there's no need for sun-producing plants.

Trivia

 * Sunflowers, Sun-shrooms, Garlics, Umbrella Leaves, Marigolds, and Planterns never come on Conveyor-Belt Levels, although Umbrella Leaves, Marigolds, Garlics, and Planterns can appear in It's Raining Seeds.
 * The player never receives Upgrade Plants or the Imitater, most likely because it would not make sense to have them if the player had not 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).
 * In the iPhone and Android versions, the belt is on the side with the plants scrolling upward.
 * The original concept of the conveyor belt was for it to be used to randomly load plants for use on each level instead of selecting plants.
 * When playing the final level of a stage, the player will only receive plants obtained in the stage (except the Lily Pad in 4-10, the Jalapeno and Ice-shroom in 5-10, the Wall-nut in Ancient Egypt - Day 8 (Day 11 pre-1.7), Coconut Cannon and the Spikeweed in Wild West Day 10 (pre-1.7), and Kernel-Pult in Dark Ages - Night 20).
 * On the iOS and Android versions, the ?-10 levels do not play Ultimate Battle Music when played in Quick Play. Instead it plays the level's regular theme.