Probably better and correct way is to use :label key and keep :button_html for styling
<%= form.action :submit, :label => "Submit", :button_html => { :class => "lagoon" } %>
I think best idea is to use I18n keys. Check Formtastic docs:
Formtastic decides which label to use in the following order:
- :label # :label => "Choose Title"
- Formtastic i18n # if either :label => true || i18n_lookups_by_default = true (see Internationalization)
- Activerecord i18n # if localization file found for the given attribute
- label_str_method # if nothing provided this defaults to :humanize but can be set to a custom method
https://github.com/justinfrench/formtastic