What to plant this week in Edmonton, AB
With average last frost still looming until May 12, Edmonton gardeners are in a tight window where early spring warmth is fleeting and late frosts remain a real threat. While you can finally start hardening off your Garlic indoors or check on overwintered crops, the air remains crisp enough to snap back any tender seedlings not yet protected under row covers.
The next 7 days
Edmonton, ABGrowing in Edmonton right now
- Edmonton's heavy clay soils retain moisture well in winter but freeze solid early; avoid working garden beds until after May 12 to prevent soil compaction that delays root growth.
- Be vigilant with wind protection for newly transplanted herbs like Basil and Shiso, as the Bow River valley often brings sudden gusts that can damage delicate foliage before mid-June.
- Extend your growing season by utilizing north-facing slopes for early planting of cold-tolerant crops like Leeks and Rutabaga, which benefit from slower warming rates in our short summer.
- Prioritize mulching around heat-loving harvests like Watermelon and Honeydew Melon to keep soil temperatures stable against the region's rapid temperature swings.
Sow this week
1 crops- Garlic
Transplant this week
Nothing is due to go out this week.
Harvest soon
46 crops- Basil
- Beefsteak Tomato
- Bell Pepper
- Borage
- Brussels Sprouts
- Bush Bean
- Cantaloupe
- Celery
- Cleome (Spider Flower)
- Cosmos
- Cowpea (Black-Eyed Pea)
- Cucumber
- Dahlia
- Edamame
- Fennel
- Flour Corn
- French Marigold
- Garden Verbena
- Garlic
- Habanero Pepper
- Honeydew Melon
- Jalapeño
- Leek
- Lima Bean
- Loofah (Luffa)
- Marconi Pepper
- Nasturtium
- Ornamental Sweet Potato Vine
- Parsnip
- Pole Bean
- Potato
- Pumpkin
- Rutabaga
- Scarlet Runner Bean
- Shiso (Japanese Basil)
- Summer Savory
- Sunflower
- Sweet Corn
- Thai Basil
- Tomatillo
- Vinca (Madagascar Periwinkle)
- Watermelon
- Winter Squash
- Yellow Summer Squash
- Zinnia
- Zucchini
Seasonal tips
- Mulch around potatoes and squash to retain moisture as summer heat peaks.
- Deadhead Cosmos and Zinnias regularly to encourage more blooms throughout the season.
- Space newly harvested Brassicas like Brussels Sprouts carefully to allow room for final growth.
Pest & disease watch
- Watch for early-season aphid colonies on Brassicas like Brussels Sprouts as they emerge from dormancy, especially in sheltered urban pockets.
- Monitor for cutworms attacking young Tomato and Pepper seedlings planted near compost piles where larvae often overwinter.
- Keep an eye out for powdery mildew on Fennel and Celery as humidity rises during our brief, wet late-May weather patterns.
Watering this week
Water deeply at the base of large crops like pumpkins and squash in the early morning to reduce evaporation.
Now is an excellent time to start planning your garlic planting schedule for next fall, as it requires cool soil to establish roots before winter.
Edmonton gardening questions
3Can I plant my Garlic cloves outside now in Edmonton?
Yes, this is the ideal time to sow hardneck Garlic varieties directly into prepared soil before the ground freezes again. Ensure you place them 2 inches deep with tips pointing up to avoid winter heaving in our harsh freeze cycles.
When should I expect my Beefsteak Tomatoes and Bell Peppers to ripen?
Given our average first frost on September 25, these heat-loving crops need immediate attention to speed up maturation. Apply a bit more nitrogen fertilizer now to boost foliage growth while protecting them from any late frost events.
How do I protect my Zinnias and Cosmos from Edmonton's early snow?
Since our first frost can hit as early as September 25, plan to harvest or cut back these annuals just before mid-September. Mulch the base lightly with dry straw if a late October frost threatens, though most will naturally die back by then.
Other cities in zone 4a
2See the full zone 4a guide → · Plan your Edmonton garden in SproutGuide →