Plant upgrade system

Plants upgrade system is a feature in Plants vs. Zombies 2 introduced in the 5.7.1 update.

Overview
Plants are leveled up by collecting seed packets, can be only obtained via Pinãtas. After upgrading plants, the stats of plants are increased, which are sun cost, damage, hp and others. However, not all plants' stats are increased per level. The player has to spend a HUGE amount of coins to upgrade. The maximum level of plants is 20. Now with the level up system, instant-kills do more damage, defensive plants can take more damage, Potato Mine arms faster, stunning/freezing plants increased time, plant food effects are stronger, expensive plants get cheaper, Citron, Chomper, Coconut Cannon, Toadstool, Banana Launcher and Missile Toe charge faster, very slow recharging plants recharge faster!

Strategies
Don't upgrade plants which you don't prefer to use, as it only causes a waste of coins. Upgrading instant use plants is useful, because instant use plants usually take a long time to reload. Upgrading them will allow you to deal more damage while planting them more often

Trivia

 * Projectile-shooting plants' projectiles' outlook changes by levels.
 * Gold Leaf, Imitater, Marigold, and Thyme Warp cannot be upgraded.
 * Gold Leaf and Thyme Warp, however, will be upgradable in future updates.
 * Plants are capped at levels 3 to 5. This cap will be increased in future updates.
 * Bonus seed packets can be any premium plant from the game, even if the player doesn't have it or even if it is not available in the store.
 * Player's House and Ancient Egypt seed packets are shared in Ancient Egypt pinãtas.