Ontario · Growing Zone 5b
Gardeners in Sault Ste. Marie, ON can expect the average last spring frost around May 10, and the first fall frost around October 7, based on historical Environment Canada frost data for the area. That gives Sault Ste. Marie a frost-free growing season of roughly 150 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.
You have your Sault Ste. Marie frost dates. Now put them to work: GrowBlock counts back your indoor seed-starting weeks, marks your safe planting day, warns you before a frost, and lays your whole season out on one timeline.
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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 Sault Ste. Marie's first fall frost approaches in October, it's time to plan the last harvests for anything frost-sensitive still in the ground.
Approximate dates for common crops in Sault Ste. Marie, worked out from the local last frost around May 10. Warm crops go out after frost, cold-hardy crops a few weeks before it, and anything with an indoor start is counted back from its sow date.
| Crop | Start indoors | Sow / transplant out | Approx. harvest |
|---|---|---|---|
| 🍅 Tomato | April 5 | May 24 | August 12 |
| 🌶️ Pepper | March 22 | May 24 | August 7 |
| 🥒 Cucumber | — | May 17 | July 14 |
| 🥬 Zucchini | — | May 17 | July 6 |
| 🥬 Lettuce | — | April 19 | June 3 |
| 🥬 Spinach | — | April 19 | June 6 |
| 🫛 Peas | — | April 19 | June 20 |
| 🥕 Carrots | — | April 19 | June 26 |
| 🫘 Bush beans | — | May 10 | June 29 |
| 🥬 Kale | March 22 | April 19 | June 13 |
Guideline dates from Sault Ste. Marie's average frost window, not a guarantee. GrowBlock tunes these to each variety you plant and adjusts as you build your beds.
This calendar is a starting point. In GrowBlock every date is tuned to the exact varieties you plant and updates as you lay out your beds, and you can share the plan with whoever you garden with, changes show up for both of you.
Build your Sault Ste. Marie garden planAround May 10 on average, though it can vary by a week or two either way depending on the year.
Sault Ste. Marie is in zone 5b, with a frost-free season of about 150 days.
Now that you have your dates, here is how to put them to work through the season:
More how-to on the GrowBlock gardening blog.
See frost dates for all Canadian cities covered by GrowBlock.