Alberta · Growing Zone 4a
Gardeners in Calgary, AB can expect the average last spring frost around June 4, and the first fall frost around September 17, based on historical Environment Canada frost data for the area. That gives Calgary a frost-free growing season of roughly 105 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 Calgary 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.
Plan your Calgary garden freeFree forever for one garden, no credit card. Built for Canadian gardeners.
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 Calgary's first fall frost approaches in September, it's time to plan the last harvests for anything frost-sensitive still in the ground.
Approximate dates for common crops in Calgary, worked out from the local last frost around June 4. 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 30 | June 18 | September 6 |
| 🌶️ Pepper | April 16 | June 18 | September 1 |
| 🥒 Cucumber | — | June 11 | August 8 |
| 🥬 Zucchini | — | June 11 | July 31 |
| 🥬 Lettuce | — | May 14 | June 28 |
| 🥬 Spinach | — | May 14 | July 1 |
| 🫛 Peas | — | May 14 | July 15 |
| 🥕 Carrots | — | May 14 | July 21 |
| 🫘 Bush beans | — | June 4 | July 24 |
| 🥬 Kale | April 16 | May 14 | July 8 |
Guideline dates from Calgary'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 Calgary garden planAround June 4 on average, though it can vary by a week or two either way depending on the year.
Calgary is in zone 4a, with a frost-free season of about 105 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.