Ontario · Growing Zone 6a
Gardeners in Guelph, ON can expect the average last spring frost around April 22, and the first fall frost around October 27, based on historical Environment Canada frost data for the area. That gives Guelph a frost-free growing season of roughly 188 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 Guelph 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 Guelph'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 Guelph, worked out from the local last frost around April 22. 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 | March 18 | May 6 | July 25 |
| 🌶️ Pepper | March 4 | May 6 | July 20 |
| 🥒 Cucumber | — | April 29 | June 26 |
| 🥬 Zucchini | — | April 29 | June 18 |
| 🥬 Lettuce | — | April 1 | May 16 |
| 🥬 Spinach | — | April 1 | May 19 |
| 🫛 Peas | — | April 1 | June 2 |
| 🥕 Carrots | — | April 1 | June 8 |
| 🫘 Bush beans | — | April 22 | June 11 |
| 🥬 Kale | March 4 | April 1 | May 26 |
Guideline dates from Guelph'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 Guelph garden planAround April 22 on average, though it can vary by a week or two either way depending on the year.
Guelph is in zone 6a, with a frost-free season of about 188 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.