Plantern

The Plantern is a plant obtained in the fog area that will illuminate and disperse a large area of fog (5x7), allowing the player to see approaching zombies and their own defense within the cleared radius, like the Torchwood. They can be planted anywhere, but are only used for their real purpose in the Fog and Vasebreaker levels. Technically, like the Grave Buster, the Plantern is not actually a Night plant, because it is not a Mushroom, and therefore, it does not need to be placed in the Mushroom Garden to grow.

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

Usage
The only purpose of the Plantern is to illuminate areas of fog, so plant it within the foggy area on the right side of the screen to push it back, 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. In Vasebreaker, it is used to reveal, what the vases contain within a 3x3 range. It is useful in early fog levels, but less effective and more space-consuming than the Blover, making it pretty useless later on.

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. You should plant only two Planterns in a level, place it near the pool on the fourth row to the right side of the lawn.

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. Try to break a vase in the middle of a 3x3 square and plant the Plantern there.

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. However, it depends on luck whether you will receive the seed packet or not.

Survival: Fog and Survival: Fog (Hard)
In Survival: Fog and Survival: Fog (Hard), use Planterns in the usual way. It is recommended that they are planted during the first two 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, although there is the loss of sun every time you use the Blover. The Torchwood is also a viable replacement for Planterns, as it doubles the firepower of all peashooting plants in addition to clearing fog, but it clears a much smaller area of fog than a Plantern. It is suggested to use a Pumpkin around your Plantern to prevent zombies from eating it easily. Also, Garlic can be placed in front of the Plantern to divert zombies from eating your Plantern easily, while reinforced with Spikerock in front of the Garlic for increased damage.

Trivia

 * The Plantern, the Torchwood, and the Sea-shroom are the only plants with visible roots.
 * Only the Torchwood, the Blover and the Plantern are able to make fog disappear.
 * Its range, rather than being one lane as the Almanac states, is actually a three square radius around it. Due to this, planting it on the far left of the player's defenses will reveal nothing.
 * Also, in Vasebreaker, its range is only 3x3, not 5x7.
 * The Plantern is the only plant with orange eyes.
 * The slow recharge time for Planterns is likely to make the player protect them more wisely so they can't just plant one anywhere immediately as soon as they get eaten.
 * The Plantern is one of the two non-mushroom plants that have a night background in the Suburban Almanac, with the other one being the Grave Buster.
 * If a Plantern is planted in Survival: Fog or Survival: Fog (Hard), every time after reselecting plants, fog will appear around the area it covers for about a second, then recede.
 * The name "Plantern" is a portmanteau of the words plant and lantern.
 * The Plantern, when planted, has an illuminating sound.
 * In the iPhone version of Zen Garden, the Plantern casts a light.
 * The Plantern is one of the plants that's not available in Versus Mode. The others are Lily Pad, Tangle Kelp, Sea-shroom, Blover, Flower Pot, and Marigold.
 * The Plantern and the Torchwood are the only fog-affecting plants which make fog stay away infinitely until they get eaten. The Blover clears the fog for a while, but then it comes back.
 * On the iPad version of Plants vs. Zombies, the Plantern only has one leaf in each corner of the lantern, instead of three. However, the seed packet shows three leaves.
 * An Imitater Plantern's eyes are barely visible.
 * A zombie will automatically go on the lane of a newly planted Plantern, possibly to make the game harder.
 * The Plantern in Plants vs. Zombies: All Stars looks almost identical.