What to plant this week in Quebec City, QC
With the last frost typically passing in mid-May and night temps still dipping near -25°F, Quebec City gardeners are pivoting from early spring starts to hardening off cool-weather crops for a summer harvest. This week marks the start of transplanting warmth-loving varieties like Beefsteak Tomatoes and Basil as we move past our critical frost window toward October's first freeze.
The next 7 days
Quebec City, QCGrowing in Quebec City right now
- Protect young Brassicas like Brussels Sprouts and Leeks from sudden late spring chills common in the St. Lawrence valley using row covers until soils fully warm.
- Take advantage of short growing days by planting Sunflowers, Zinnias, and Corn immediately to ensure they mature before the October 1 frost date.
- Amend heavy clay soils typical of the region with organic matter to improve drainage for water-sensitive crops like Cucumbers and Eggplant.
- Start seeds indoors now for Borage and Cleome if you missed the window, as these thrive in Quebec's late spring heat waves.
Sow this week
No direct sowing windows open this week.
Transplant this week
Nothing is due to go out this week.
Harvest soon
50 crops- Basil
- Beefsteak Tomato
- Bell Pepper
- Borage
- Brussels Sprouts
- Bush Bean
- Cantaloupe
- Celery
- Cleome (Spider Flower)
- Cosmos
- Cowpea (Black-Eyed Pea)
- Cucumber
- Dahlia
- Edamame
- Eggplant
- Fennel
- Flour Corn
- French Marigold
- Garden Geranium (Zonal)
- Garden Verbena
- Garlic
- Habanero Pepper
- Honeydew Melon
- Jalapeño
- Lantana
- Leek
- Lima Bean
- Loofah (Luffa)
- Marconi Pepper
- Nasturtium
- Ornamental Sweet Potato Vine
- Parsnip
- Petunia
- 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
- Finish succession planting bush beans and pole beans to extend the summer harvest window.
- Apply a thick layer of compost around root vegetables like parsnips and rutabagas as they mature.
- Deadhead spent flowers on zinnias, cosmos, and marigolds to encourage more blooms all season long.
Pest & disease watch
- Watch for Cabbage Loopers and Aphids on newly transplanted Brassicas as temperatures stabilize above 50°F.
- Monitor Squash Vine Borers on Pumpkins and Zucchini as humidity rises later this month.
- Check for early Potato Tuber Moth activity in fields around the city outskirts.
Watering this week
Water deeply at the soil line in the morning to prevent fungal issues on these thirsty summer crops.
Don't forget to save seeds from your favorite varieties like Beefsteak Tomato or Yellow Summer Squash before they ripen fully this week.
Quebec City gardening questions
3Can I plant my Tomatoes and Peppers outside now?
Yes, you can move hardy varieties like Beefsteak Tomatoes and Bell Peppers out as long as there is no forecast for frost below 28°F. Ensure they get a few days of acclimation in a sheltered spot before full sun exposure.
When should I plant Garlic for winter harvest?
Garlic goes in the ground now while soil moisture is adequate, aiming to be established before the heavy snows of late November or early December. Choose hardy varieties suited for Quebec's long cold winters to ensure bulb formation underground.
How do I extend my season for Summer Squash and Zucchini?
Mulch heavily around the base of your plants with straw or shredded leaves to retain heat in the soil and protect roots from temperature swings. Install a frost cloth over the vines at night until after October 1 to catch any late-season harvests.
Other cities in zone 4b
3See the full zone 4b guide → · Plan your Quebec City garden in SproutGuide →