You can Schedule your Web Form activity in QuintaDB. You can set a timeframe when form will be active and in other time if will be disabled
If you want to close form for a while, but don't want to remove iframe code from your page, you can use "Schedule Form Activity" option.
Which can be found in Form widget menu , in Security tab.
You need to enter start and end dates and message, which will be shown while form will be disabled.