What to plant this week in Winnipeg, MB
Winnipeg gardeners are currently in a critical late-season window, with the average first frost arriving just days away on September 20th. This week marks the absolute deadline to bring all heat-loving crops like cherry tomatoes and yellow summer squash indoors before temperatures plummet toward -35°F.
The next 7 days
Winnipeg, MBGrowing in Winnipeg right now
- Hail is common in Manitoba late summer; use row covers immediately for vulnerable heads of cabbage, cauliflower, and zucchini to protect against physical damage.
- Winnipeg's clay-heavy soils hold moisture too long near frost; ensure drainage containers are elevated or potted plants have plenty of room to move indoors quickly.
- Wind speeds frequently exceed 40 km/h as storms approach the Red River valley; secure all outdoor trellises for pole beans and snapdragons now before high winds knock them over.
- Take advantage of this week's harvest window for beets, carrots, and Swiss chard while soil is still workable; cover harvested beds with black plastic to suppress weeds in the coming freeze.
Sow this week
No direct sowing windows open this week.
Transplant this week
Nothing is due to go out this week.
Harvest soon
38 crops- Bachelor's Button (Cornflower)
- Beet
- Borage
- Bush Bean
- Cabbage
- Calendula
- Carrot
- Cauliflower
- Cherry Tomato
- Chervil
- Cleome (Spider Flower)
- Collard Greens
- Cosmos
- Dill
- Fava (Broad) Bean
- French Marigold
- Garlic
- German Chamomile
- Kale
- Lettuce
- Napa Cabbage
- Onion
- Pansy
- Parsley
- Pole Bean
- Potato
- Scallion (Bunching Onion)
- Scarlet Runner Bean
- Shallot
- Snapdragon
- Sweet Alyssum
- Swiss Chard
- Tomato
- Turnip
- Vinca (Madagascar Periwinkle)
- Yellow Summer Squash
- Zinnia
- Zucchini
Seasonal tips
- Continue succession sowing bush beans and pole beans every two weeks to extend your harvest through summer.
- Mulch around young tomatoes and peppers to retain moisture as soil temperatures stabilize after the frost-free date.
- Pinch back the tops of Swiss chard and kale to encourage bushier growth before autumn frosts arrive.
Pest & disease watch
- Cutworms often make a final raid on young tomato and bean seedlings just before frost; check stems at dawn and hand-pick any curled larvae.
- Aphid populations can explode quickly in late summer heat; inspect the undersides of kale, collard greens, and lettuces for sticky honeydew or distorted leaves.
- Late-blooming Zinnias and Cosmos may attract Japanese beetles which will skeletonize foliage rapidly if not removed manually this week.
Watering this week
Provide deep watering two to three times per week, ensuring consistent moisture for seedlings like dill and chervil.
Harvest zucchini and yellow summer squash when they are small to prevent the plant from going into a dormant phase.
Winnipeg gardening questions
3Can I still direct sow anything into the ground in Winnipeg right now?
No new seeds should be sown directly into the open ground as soil temperatures are dropping rapidly and frost risk is immediate. Focus entirely on harvesting existing crops and bringing annuals indoors instead.
How do I save my tomato crop before September 20th?
Bring all tomatoes, including cherry varieties, into a warm garage or sunroom immediately; remove them from the vine to prevent rot during transport if necessary.
What should I do with my snapdragons and bachelor's buttons this week?
These perennials are frost-tender; cut the flowering stems down to 6 inches above ground level to encourage root survival over winter.
Other cities in zone 3b
4See the full zone 3b guide → · Plan your Winnipeg garden in SproutGuide →