I'm planning on watching Fear the Walking Dead but I read that it's a spin off/prequel of the Walking Dead.
Is it quite dependent on The Walking Dead or can it be watched on its own ?
No, you don't have to.
The two series have a similar name and are set in the same world, but have nothing to do with each other, not the same character, place or even the same time frame (The events in Fear the Walking Dead happens first).
I don't watch either series, but I believe you can CURRENTLY watch either without seeing the other.
However, the two series may be coming together with either a crossover episode and/or a shared character at some point in the near future, so this might change somewhat pending how much weight this character originally holds in whichever show he or she originates. However, I still speculate being a Better Call Saul fan that has not seen more then the Pilot episode of Breaking Bad, it will be watchable, but just that there will be more there for fans that know the character from the other show.
Vanity Fair - Robert Kirkman Interview - October 8, 2017
At New York Comic Con on Saturday night, fans of the zombie drama packed Madison Square Garden for a panel, during which Robert Kirkman revealed a very exciting prospect for the months to come: a crossover episode between Walking Dead and its prequel, Fear the Walking Dead.
As man who wrote the original Walking Dead comics explained, Fear the Walking Dead was designed to stand on its own. Now, though, “I think that we’ve finally gotten to a place with Fear the Walking Dead where it has its own identity where we can play with some things,” Kirkman said. “So what I’m going to say, and this is all I’m going to say, is that there are two Walking Dead shows. I’m not going to name them. But there are two. There’s one character that is going to go from one show that I will not name and appear in the other show, which I will not name.” https://www.vanityfair.com/hollywood/2017/10/walking-dead-crossover-nycc-fear-the-walking-dead-season-8
"Fear the Walking Dead" is a prequel to the "Walking Dead" series which was launched as a "when the outbreak began" series. While Walking Dead is not necessary, apparently there might be a crossover episode on the line, but as of now Fear the Walking Dead is strictly independent!
I agree with all of you. You don't need to watch one to watch the other. They could be "connected" by the same theme ... but "that's all".
In any case, if you want to watch Walking Dead, I recommend you to read also comic books. Stories are quite different, but are both "cool". Enven if I prefer the comic books.