Do WiFi signals affect plant growth?

Recent findings by five girls from a primary school in Denmark have proved that plant growth could be affected by WiFi signals. The five girls decided to carry out the experiment after noticing that when they slept with mobile phones near their heads in the night, they realized they could not focus on their studies the following day.
So in order to find out if wireless signals truly affect the human brains, they decided to make do with the equipment they had at their disposal, they placed plants near WiFi routers---what they found out shocked them.
The group took six trays of a garden cress herb and placed them in one room without WiFi routers, and another six tray with same seeds placed with WiFi routers in a different room.
The seeds placed in a room without WiFi routers, after during 12 days of the experiment, grew well while the other seeds placed near the WiFi routers did not. As you can see in the photo above, the seeds placed near the WiFi routers died.