How long does it take for magnet shroom to recharge?

I noticed that recently when a magnet shroom sucks a metal item it needs to recharge. Most of my defense is dependent on magnet shroom for defense against metallic zombies. However the magnet shrooms are taking a while to disintegrate whatever metal item it has sucked. ( This is optional, you don't have to answer it.) Should I keep depending on magnet shrooms?

Solution 1:

It takes 10 seconds for it to recharge. It can be quite effective against Football Zombies, so you could integrate it in your defense, should you have troubles with them.
Unfortunately, it makes Digger Zombies pop out of the ground (because it sucks in their pickaxes), potentially causing them to eat plants from your middle columns.