Blind Faith

Complete an Extremely Foggy level and never use Planterns or Blovers.

Strategy
The easiest way to get it is to play level 4-8, because it's extremely foggy, one of the requirements for the level.

To get it, you should pick the following:

Sun-shroom

Puff-shroom

Scaredy-shroom

Wall-nut

Gloom-shroom

As the achievement states, you can't use the fog removers. If you have the Plantern or Blover, you can't achieve this. It isn't very different like the pool level from the day, but you can beat it. Gloom-shrooms are cheaper than Threepeaters.

Note: Torchwoods don't count as Planterns or Blovers.

Note: Completing a non-extremely foggy level without using any Planterns or Blovers won't unlock this achievement.