Resize fields in Django Admin

Django tends to fill up horizontal space when adding or editing entries on the admin, but, in some cases, is a real waste of space, when, i.e., editing a date field, 8 characters wide, or a CharField, also 6 or 8 chars wide, and then the edit box goes up to 15 or 20 chars.

How can I tell the admin how wide a textbox should be, or the height of a TextField edit box?

You should use ModelAdmin.formfield_overrides.

It is quite easy - in admin.py, define:

from django.forms import TextInput, Textarea
from django.db import models

class YourModelAdmin(admin.ModelAdmin):
    formfield_overrides = {
        models.CharField: {'widget': TextInput(attrs={'size':'20'})},
        models.TextField: {'widget': Textarea(attrs={'rows':4, 'cols':40})},
    }

admin.site.register(YourModel, YourModelAdmin)