[ruby-on-rails-3] How can I change cols of textarea in twitter-bootstrap?

Another option is to split off the textarea in the Site.css as follows:

/* Set width on the form input elements since they're 100% wide by default */

input,
select {

  max-width: 280px;
}

textarea {

  /*max-width: 280px;*/
  max-width: 500px;
  width: 280px;
  height: 200px;
}

also (in my MVC 5) add ref to textarea:

@Html.TextAreaFor(model => ................... @class = "form-control", @id="textarea"............

It worked for me