How to keep all my django applications in specific folder

You can do this very easily, but you need to change the settings.py to look like this:

INSTALLED_APPS = (
    'apps.app1',
    'apps.app2',
    # ...
)

And your urls.py to look like this:

urlpatterns = patterns('', 
    (r'^app1/',include('apps.app1')),    
    (r'^app2/',include('apps.app2')),    
)

.. and modify any imports to point to the app location

How about you utilize the BASE_DIR variable already present in the settings.py.

Just add the following:

import sys
sys.path.insert(0, os.path.join(BASE_DIR, 'apps'))

Hope this helps.

As a slight variant to Berhard Vallant's or Anshuman's answers, here is an alternative snippet to place in settings.py

import os
import sys  # Insert this line

BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))

# Insert the two lines below
APPS_DIR = os.path.join(BASE_DIR, '<your_project_dir_name>/apps/')
sys.path.insert(0, APPS_DIR)

Doing it in this way has the added benefit that your template directories are cleaner as they will look like below. Without the APPS_DIR variable, there will be a lot of repitition of <your_project_dir_name>/apps/ within the DIRS list of the TEMPLATES list.

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [
            os.path.join(APPS_DIR, '<app_name>/templates/<app_name>'),
            os.path.join(APPS_DIR, '<app_name>/templates/<app_name>'),
            ...
        ],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

You can list the apps within the INSTALLED_APPS list as normal with either the short-form name given in apps.py or by using the long-form syntax of appname.apps.AppnameConfig replacing appname with your app's name.

You can add your apps folder to your python path by inserting the following in your settings.py:

import os
import sys

PROJECT_ROOT = os.path.dirname(__file__)
sys.path.insert(0, os.path.join(PROJECT_ROOT, 'apps'))

Then you can use all the apps in this folder just in the same way as they were in your project root!