When to Plant Carrots in Ottawa, ON
Published: April 24, 2026 · Updated: April 27, 2026
Carrots must be direct-sown — they cannot be transplanted without forking the root. Loose, rock-free soil at least 12 inches deep is essential for straight roots.
Ottawa's Canadian Zone 5b (USDA 5a) continental climate brings cold winters, hot summers, and higher frost risk than Toronto thanks to the inland location. The 153 frost-free days from early May through early October is adequate for most vegetables, but variety selection — short-season cultivars under 70 days — matters significantly.
Carrots Planting Calendar for Ottawa
Direct sow outdoors: April 8–18
Harvest window: June 17 – June 27
Minimum soil temperature: 7°C (45°F)
Days to harvest: 70–80 days
Sun requirement: Full sun
Fall crop planting: July 28–August 7 (harvest October 6)
Ottawa Climate Notes
Ottawa Valley winters are harsh. Choose short-season tomato varieties under 70 days (Stupice, Sunrise, Sub-Arctic Plenty) and transplant only after the May long weekend. Fall garden extends the productive season into October with cold-tolerant greens and brassicas.
Growing Tips for Carrots
- Direct sow ONLY — transplanting carrots causes forked, misshapen roots every time.
- Soil must be loose and rock-free to at least 12 inches deep; raised beds are ideal.
- Thin to 3-inch spacing aggressively — crowded carrots fork and grow stunted.
- Light frost improves carrot sweetness — cold converts starches to sugar; fall carrots taste better than spring.
Companion Planting in Ottawa
Pair carrot with Tomato, Onion, Leek, Rosemary for mutual benefit. Avoid planting near Dill, Parsnip, Anise, which compete with or inhibit carrot growth.
Pests and Problems to Watch in Ottawa
The most common pest and disease pressure on carrots in Ottawa comes from Carrot Fly, Wireworm, Leaf Blight, Forking from rocky soil. Floating row covers through the first 4–6 weeks after planting block adult pests from laying eggs, and a weekly scouting routine catches infestations before they damage the crop.
Other Ontario Cities
Frequently Asked Questions
When do I plant carrot in Ottawa?
Ottawa's last spring frost is around May 6. Direct sow April 8–18.
What Canadian hardiness zone is Ottawa?
Ottawa is in Canadian Zone 5b (USDA equivalent 5a). The continental inland climate delivers 153 frost-free days from May 6 to October 6, which shapes every planting date in the local calendar.
How long is Ottawa's growing season?
Ottawa has 153 frost-free days — from May 6 in spring to October 6 in fall. That is more than enough time to finish a full carrot crop (70–80 days to maturity) before the first fall frost.
Can I grow carrot in containers in Ottawa?
Yes. Container growing on balconies and decks is practical in Ottawa — choose a 5-gallon or larger dark-coloured container to warm the root zone, use a high-quality potting mix, and water daily during hot summer weather. In milder climates, containers extend both spring and fall windows by several weeks.
What is the first fall frost in Ottawa?
Ottawa's average first fall frost is October 6. For a fall carrot crop, plant around July 28–August 7 so plants mature before the first killing frost.