ddsack - It is possible to grow sweet potatoes in zone 3. But it would probably be like someone in Virginia trying to grow avocados. Can be done with certain varieties but probably not worth the trouble.Here is a video of someone growing in zone 4 Montana. They made mistakes by not growing the extra early varieties and by planting whole sweet potatoes but they did good and will do better next year with early varieties like Beauregard and o'Henry. Georgia Jets is even earlier they say and Radiance was bred especially for Canada.
RADIANCE was released by LSU Ag Center. Radiance is an orange flesh, purple-red skinned sweet potato capable of high yields in northern latitudes. It has shown superior disease resistance to fusarium wilt. This variety produces US#1 grade and total marketable yields equal or higher than ‘Covington’ and ‘Orleans’ in Candian sweetpotato production regions. It tends to have more Jumbos than ‘Covington’ and ‘Orleans’, indicative of its earliness.
https://www.youtube.com/watch?v=5WrbZx3xJkw
Mrs. Justice, I know how hard it is to find garden space. Always something like too much shade, too wet, poor soil and so on. It really doesn't take all that much space to grow a bumper crop of sweet potatoes and you are in the heart of sweet potato country. Here are a couple of my favorite sweet potato videos.
This one is an amazing harvest in a small space. The sweet potatoes are crazy shapes maybe from the loose soil.
https://www.youtube.com/watch?v=IzNIr6IbAt4
More space and a huge crop of sweet potatoes. I like this one because they tell you what the name of the varieties are.
https://www.youtube.com/watch?v=_waEdtuXeHg
I guess you can tell I love watching sweet potato videos. I guess cause it is my favorite thing to do in the garden, digging sweet potatoes.
