^ Do you need settlers for plants(corn,mutfruit,tato) to regrow? Also, does planting attract settlers? Thx in advance

I'm pretty sure a settler must be assigned to a plant for it to grow.

You can only attract settlers by building a radio beacon in the settlement you want settlers to come to. Or you can move settlers to a new settlement in workshop mode.

Yes, plants inside your settlements will regrow only if workers are assigned to them. And they don't attract new settlers.