What to plant this week in Edmonton, AB
Edmonton gardeners are in the final stretch before fall, with average first frost hitting around September 25. This week is critical for harvesting early crops like carrots and cabbage while preparing to wrap up late-blooming annuals like zinnias and cosmos by the end of September.
The next 7 days
Edmonton, ABGrowing in Edmonton right now
- Take advantage of the long daylight hours this time of year to get in a final harvest of Swiss chard and kale before temperatures dip toward -30°F overnight.
- Protect your overwintering garlic and shallots from vole damage as soil freezes, ensuring they survive until spring planting for next May 12 frost date.
- Check drainage carefully on the city's clay-heavy soils; heavy rains can still occur in September, risking root rot for remaining tomatoes and peppers.
- Clear out spent French marigolds and nasturtiums to prevent fungal spores from overwintering in your garden beds.
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
- Monitor squash plants (yellow summer squash and zucchini) for late-season powdery mildew as humidity rises before the freeze.
- Watch for cutworms on young transplants of bush beans and pole beans if you haven't finished protecting them yet.
- Check collard greens and kale leaves for cabbage loopers, which can still cause significant damage in late September.
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.
Edmonton gardening questions
3Can I still plant anything now that frost is coming?
You should stop sowing outdoors immediately since the average last frost date was May 12 and we are approaching the first frost window. Focus instead on harvesting your 'harvest soon' list like basil, borage, and collard greens before the cold sets in.
When exactly should I pull my summer tomatoes?
Harvest cherry tomatoes and other varieties immediately as they ripen; if a green fruit has turned to yellow or pink, cut it off rather than letting it freeze on the vine. Stop watering heavily once you are ready to cover plants for frost protection.
Are there specific pests I need to worry about in late Edmonton fall?
The biggest concerns now are fungal diseases like powdery mildew on squash and cabbage loopers on your brassicas before the ground freezes. Remove any diseased leaves promptly to prevent spores from surviving over winter.
Other cities in zone 4a
2See the full zone 4a guide → · Plan your Edmonton garden in SproutGuide →