Ontario · Growing Zone 5a
Gardeners in Sudbury, ON can expect the average last spring frost around May 18, and the first fall frost around September 29, based on historical Environment Canada frost data for the area. That gives Sudbury a frost-free growing season of roughly 134 days. Actual frost dates shift by a week or two year to year, so use this as a planning baseline rather than an exact guarantee, and always check your local forecast before moving tender plants outside.
Most warm-season crops (tomatoes, peppers, squash) need transplanting only after the last frost has passed, and are usually started indoors 6 to 8 weeks before that date. Cold-hardy crops (peas, lettuce, spinach) can often go in the ground a few weeks before the last frost. As Sudbury's first fall frost approaches in September, it's time to plan the last harvests for anything frost-sensitive still in the ground.
GrowBlock builds your whole season timeline around dates like these automatically, indoor seed starting, transplant windows, and harvest, tuned to Sudbury specifically.
Plan your Sudbury gardenAround May 18 on average, though it can vary by a week or two either way depending on the year.
Sudbury is in zone 5a, with a frost-free season of about 134 days.