Plantern

The Plantern will illuminate a small area of fog, allowing you to see the approaching zombies.

Usage
Plant within the foggy area on the right side of the screen to push back the fog, revealing the enemy. If Planterns are planted one square into the foggy area in the rows on either side of the pool, all of the fog will disappear aside from some scraps of it in the corners of the screen. They can only be planted at night without a coffee bean.

Suburban Almanac Entry
Plantern

Planterns light up an area, letting you see through fog.

Range: one lane

Special: Lets you see through fog

Plantern defies science. He just does. Other plants eat light and excrete oxygen; Plantern eats darkness and excretes light. Plantern's cagey about how he does it. "I'm not gonna say 'sorcery,' I wouldn't use the term 'dark forces,' I just... I think I've said enough."

Cost: 25

Recharge: slow

Standard Levels
It is a good idea to put Planterns behind defensive plants such as Wall-nuts or Garlic to keep them from being eaten, or inside a Pumpkin if you can. Note that Planterns are ONLY useful in the Fog levels (Levels 4-1 to 4-10).

Vasebreaker
The Plantern will reveal the contents of any adjacent or diagonally-adjacent vases - up to eight at most. In an emergency, a Plantern may be used as a poor-man's blockade to briefly delay zombies while attempting to kill them with other plants. Ideally. it should be placed in the middle of as many vases as possible.

It's Raining Seeds Mini-game
In the Mini-game It's Raining Seeds, there is fog, so use Planterns the same way that you do in the Adventure Mode levels.

Survival:Fog and Survival:Fog (Hard)
In Survival: Fog and Survival: Fog (hard), use Planterns normally. It is recommended that they are planted during the first 2 flags (before you get to choose new seed packets). Alternatively, for the Survival levels, you can use Blovers instead, which also gets rid of Balloon Zombies, and makes room for more plants. The Torchwood is also a viable replacement for Planterns as it doubles the firepower of all pea-shooting plants in addition to clearing fog.