When you say catch do you mean the starter isn't engaging?
Block heaters are a good idea no matter what. They help keep the fluids warmer in the motor which leads to a lot less wear on the internals during a cold start.
If the starter is going bad or sticking a block heater probably won't help much. You battery may also be weak which can cause slow starts or even no starts if the voltage drops. In that case a new battery or a battery blanket may solve your issues.
Originally Posted by Tsircou
So I've been noticing that the colder it is outside and the longer my car sits outside the harder it is to start. She'll try to turn over a couple times and on about the 4th time will catch. Is this mostly due to the cold? And if so will a engine block heater help this problem. Thanks in advance for the help!