When to Plant Turnips in Ottawa, ON
Published: April 24, 2026 · Updated: April 27, 2026
Fast-growing cool-season root crop — some varieties ready in just 35 days. Best planted in late summer for fall harvest; frost sweetens the roots. Direct sow only; resents transplanting.
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.
Turnips Planting Calendar for Ottawa
Direct sow outdoors: April 15–25
Harvest window: May 20 – June 14
Minimum soil temperature: 4°C (40°F)
Days to harvest: 35–60 days
Sun requirement: Full sun to partial shade
Fall crop planting: August 11–21 (harvest September 15)
⚠ Direct sow turnips 2–4 weeks before last frost for spring crop. Best planted in late summer (6–8 weeks before first fall frost) for fall harvest — frost sweetens the roots. Fast-growing: some varieties ready in just 35 days.
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 Turnips
- Thin seedlings to 4-inch spacing when plants are 3 inches tall — crowded turnips produce small woody roots.
- Both roots AND greens are edible — harvest baby turnip greens 4 weeks after sowing, roots 5–9 weeks.
- Fall turnips are sweetest — plant 8 weeks before first frost and let cold weather convert starches to sugars.
- Succession plant every 2–3 weeks for continuous harvest through spring; skip summer heat and resume in fall.
Companion Planting in Ottawa
Pair turnip with Pea, Mint, Rosemary, Thyme for mutual benefit. Avoid planting near Potato, Radish, which compete with or inhibit turnip growth.
Pests and Problems to Watch in Ottawa
The most common pest and disease pressure on turnips in Ottawa comes from Flea Beetle, Aphid, Cabbage Root Maggot. 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.
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Frequently Asked Questions
When do I plant turnip in Ottawa?
Ottawa's last spring frost is around May 6. Direct sow April 15–25.
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 turnip crop (35–60 days to maturity) before the first fall frost.
Can I grow turnip 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 turnip crop, plant around August 11–21 so plants mature before the first killing frost.