How do I plant onions? Also what is the latest time that I can plant potatoes?

Welcome @kimi! We have a very powerful tool which you can find in the Webapps selection, on the left sidebar, called Garden Planting Calendar. This app will tell you when to plant your onions. I'll let others discuss proper planting techniques but for planting times, we've got you covered. Good luck!

Direct link here: http://garden.org/apps/calenda...

I buy onion starts, I order in Nov. @ Dixondale Farms for delivery in March when it is time to plant them where I live. Some folks plant sets which are small bulbs. You can also grow them from seed too, but I'm not very good at that yet.