Dark, leafy greens are your easiest source of vitamin K.
One way I always remind myself of what food to eat when I need vitamin K is that Kale, starts with a K... And Kale is very high in vitamin K! Of course, kale is also oh-so-very "in" right now, so it's not that difficult to find in most grocery stores.
Other dark greens that are high in vitamin K:
- spinach
- bassil
- brussel sprouts
- asparagus
- leeks
Other foods like olive oil, soybeans, and chilli powder are also good sources of vitamin K.
But really, if you're looking for a super boost, dark green vegetables are your best bet. A simple way to get that boost is to throw some kale or spinach in a soup or stir fry. Do so only in the last couple of minutes of cooking as it doesn't take long for the leaves to get wilted, especially for spinach.
Here's a few other ideas you could try out:
http://www.besthealthmag.ca/eat-well/cooking/11-ways-to-eat-dark-green-vegetables