What to plant this week in Calgary, AB
With the average last frost date in Calgary sitting around May 12, this week marks a critical transition as many hardy crops like kale and cabbage begin their harvest season while you prepare for mid-May transplants. The city's semi-arid climate means you must maximize every drop of moisture now that soils are warming up after winter's freeze.
The next 7 days
Calgary, ABGrowing in Calgary right now
- Calgary's clay-heavy loam retains water but drains poorly; amend heavy spots with compost before planting carrots and onions to prevent stunting.
- West wind exposure is intense in the foothills; use windbreaks or row covers for delicate seedlings like Swiss chard and cilantro to prevent physical damage.
- With low natural rainfall, apply a 2-inch mulch layer immediately around tomatoes and peppers to conserve moisture and keep soil temperatures stable.
- Take advantage of the short summer window by prioritizing quick harvest crops like bush beans and snap peas before the early September frost hits.
Sow this week
No direct sowing windows open this week.
Transplant this week
Nothing is due to go out this week.
Harvest soon
46 crops- Bachelor's Button (Cornflower)
- Basil
- Beet
- Bell Pepper
- Borage
- Bush Bean
- Cabbage
- Carrot
- Cauliflower
- Cherry Tomato
- Cleome (Spider Flower)
- Collard Greens
- Cosmos
- Cowpea (Black-Eyed Pea)
- Cucumber
- Dill
- Fava (Broad) Bean
- Fennel
- French Marigold
- Garlic
- German Chamomile
- Ground Cherry
- Kale
- Napa Cabbage
- Nasturtium
- Onion
- Ornamental Sweet Potato Vine
- Pansy
- Parsley
- Pole Bean
- Potato
- Rutabaga
- Scallion (Bunching Onion)
- Scarlet Runner Bean
- Shallot
- Shishito Pepper
- Snapdragon
- Summer Savory
- Sweet Corn
- Swiss Chard
- Thai Basil
- Tomato
- Vinca (Madagascar Periwinkle)
- Yellow Summer Squash
- Zinnia
- Zucchini
Seasonal tips
- Continue succession sowing quick-growing crops like bush beans and lettuce to extend your summer harvest through September 25.
- Deadhead spent flowers on Cosmos and Zinnia to encourage more blooms before the first frost.
- Apply a light layer of mulch around established perennials like Pansies and Ornamental Sweet Potato Vines to retain soil moisture as nights get cooler.
Pest & disease watch
- Aphids are returning aggressively on young tomato and pepper leaves; monitor closely as Calgary's warm days trigger rapid population growth in late spring.
- Slugs thrive in the city's microclimates near irrigation lines, particularly targeting leafy greens like kale and collard greens during damp evenings.
- Root maggots pose a threat to transplanted carrots and beets; consider using floating row covers immediately after transplanting to protect developing roots.
Watering this week
Water deeply in the morning to help plants withstand afternoon heat while reducing evaporation losses.
Harvest your Cherry Tomatoes and Bell Peppers daily to keep the plant producing and prevent over-ripening before the first frost date.
Calgary gardening questions
3When is the safest time to move my tomato seedlings outdoors in Calgary?
Wait until at least May 15, giving you two weeks of buffer past the average last frost date of May 12. Ensure nighttime temperatures have consistently stayed above 50°F before exposing your transplants to our cool evenings.
My carrots are not growing straight in my Calgary garden bed; how do I fix this?
Calgary's native clay often creates hardpan layers that deflect carrot roots; dig down an extra six inches and mix in generous amounts of compost or coarse sand before sowing.
Should I start harvesting my kale now, or wait until it gets bigger?
You can begin snipping outer leaves from your kale plants this week to encourage a second flush of growth before the summer heat slows development. This is especially useful since Calgary's growing season ends relatively early compared to southern zones.
Other cities in zone 4a
2See the full zone 4a guide → · Plan your Calgary garden in SproutGuide →