What to plant this week in Ottawa, ON
Ottawa gardeners are in the thick of late spring and early summer, with average last frost finally behind us on May 8. This week is critical for sowing warm-season staples like Zucchini and Yellow Summer Squash directly into your beds before the ground cools again. With harvests beginning soon for crops started earlier this season, you'll be picking everything from tomatoes to basil within days.
The next 7 days
Ottawa, ONGrowing in Ottawa right now
- Ottawa's clay-heavy soils can become waterlogged during our frequent spring rain showers; ensure good drainage or amend with compost before planting squash and beans.
- While the frost date is May 8, keep a blanket handy for unexpected overnight dips common in our urban heat island effect which often cools faster at night.
- Take advantage of the mild daytime warmth now to start succession planting carrots and beets next to your existing harvest rows.
- Be mindful that our limestone-rich soils in areas like Glebe or Old Ottawa South may require extra lime if you are growing acid-loving plants like blueberries not on this list.
Sow this week
2 crops- Yellow Summer Squash
- Zucchini
Transplant this week
Nothing is due to go out this week.
Harvest soon
55 crops- Bachelor's Button (Cornflower)
- Banana Pepper
- Basil
- Beet
- Bell Pepper
- Borage
- Bush Bean
- Cabbage
- Carrot
- Cauliflower
- Cherry Tomato
- Cleome (Spider Flower)
- Collard Greens
- Cosmos
- Cowpea (Black-Eyed Pea)
- Cucumber
- Dill
- Eggplant
- Fava (Broad) Bean
- Fennel
- French Marigold
- Garden Geranium (Zonal)
- Garden Verbena
- Garlic
- Ground Cherry
- Jalapeño
- Lantana
- Lima Bean
- Napa Cabbage
- Nasturtium
- Onion
- Ornamental Sweet Potato Vine
- Parsley
- Petunia
- Poblano Pepper
- Pole Bean
- Potato
- Roma Tomato
- Rutabaga
- Scallion (Bunching Onion)
- Scarlet Runner Bean
- Shallot
- Shishito Pepper
- Shiso (Japanese Basil)
- Snapdragon
- Summer Savory
- Sunflower
- Sweet Corn
- Swiss Chard
- Thai Basil
- Tomato
- Vinca (Madagascar Periwinkle)
- Yellow Summer Squash
- Zinnia
- Zucchini
Seasonal tips
- Start succession sowing bush beans and snapdragons every two weeks for a continuous harvest.
- Deadhead Cosmos and Cleome regularly to encourage more blooms throughout the summer.
- Thin out carrot and beet seedlings now to give remaining plants enough room to mature.
Pest & disease watch
- Watch closely for early slug activity on young Zucchini and Squash seedlings as damp spring weather favors them.
- Monitor your Tomato and Pepper plants for spider mites which can establish quickly in our dry summer winds by late May.
- Check Collard Greens and Cabbage for flea beetle damage which often appears before the canopy closes up.
Watering this week
Water deeply in the morning to keep roots cool and reduce evaporation during this hot season.
Harvest your first ripe cherry tomatoes today to enjoy their peak flavor while they are young and tender.
Ottawa gardening questions
3Can I transplant my tomato starts now that the frost date of May 8 has passed?
Yes, you can safely move your Tomato and Pepper seedlings outdoors now, but wait until any lingering cool nights are gone to avoid shock.
What should I do with my Zucchini seeds since they are listed as sowable now?
Direct sow your Yellow Summer Squash and Zucchini seeds into the ground today or tomorrow before the soil warms up further.
My garlic was listed for harvest soon; how do I know when it is ready?
Garlic is ready to lift when the lower leaves turn yellow and brown but about half the top foliage remains green.
Other cities in zone 5a
6See the full zone 5a guide → · Plan your Ottawa garden in SproutGuide →