Why did the Vikings not sail south in Canada?

There is not much documentation concerning why the Vikings chose not explore further south once they discovered North America, though a few reasons can be surmised based both upon the experiences they had in Vinland and Markland and their reasons for traveling. Erik the Red settled in Iceland with his father, who had been exiled from Norway for manslaughter. Erik was later exiled from Iceland for a similar reason. During this exile, Erik chose to seek land to the west of Iceland based upon reports from trading ships. He established a settlement in Greenland and lived the term of his exile there. He then returned to Iceland to gather more potential settlers and ultimately built a settlement in Greenland of 400 to 500 people. Greenland is, however, cold and lacking in a number of natural resources. This led Erik to explore further to the west where (according to the sagas) a trader had noticed, but not landed on, new lands. Erik set out for those lands and discovered Helluland (believed to be Baffin Island), Markland (likely Labrador), and Vinland (likely Newfoundland). Here he found an abundance of timber and other resources and attempted to found a settlement which would cultivate food and harvest timber to be sent to Greenland. However, hostilities with the native peoples in the area proved too much for Erik's Vikings and they abandoned the potential settlement. While there were likely more trips to North America to retrieve timber and other resources, the danger posed by Native Americans proved too high to establish a permanent foothold and, since the needs of the Greenland settlement were already met, likely discouraged further exploration.