I need some PvZA help!!

Park-n-Perish Level 16 is too hard for me! It isn't like a normal level, but you can only choose 4 Peashooters and all the close spots are covered up with tires. AND I DON'T HAVE DYNAMITE YET!! The only thing I can do is perk up my plants whenever a zombie comes in range. And it is so annoying because the range of the Peashooters barely reaches the zombies' paths!!! I know I need Lawn Mower + ZombiFreeze but does anyone else have any suggestions?