When to Plant Carrots in Ontario — 2026 Guide
City-by-city direct sow dates, a full succession planting schedule, best varieties for Ontario soils, and how Ontario compares to BC and Quebec.
When to plant carrots in Ontario is one of the more forgiving questions in the vegetable garden — carrots are cool-season vegetables that go in the ground weeks before your last frost date, not after it. Toronto gardeners can sow their first carrots in late March. Ottawa and Kingston gardeners start in mid-April. And unlike tomatoes or peppers, you can keep sowing all the way to mid-July for harvests right through October.
This guide covers first sowing dates for every major Ontario city, a complete succession planting schedule, the best carrot varieties for Ontario soils and zones, and growing tips specific to Ontario conditions.
Ontario carrot planting at a glance: First sowing 4–6 weeks before last frost — no need to wait. Toronto and Windsor: late March to early April. Ottawa and Kingston: mid to late April. Succession sow every 3 weeks through mid-July. Carrots tolerate light frost and germinate in soil as cool as 7°C. Frost dates use Environment and Climate Change Canada climate normals (1991–2020).
When should you plant carrots where you garden?
Get your city's frost dates, indoor seed-starting dates, and this week's planting jobs — three free tools.
Outside Ontario? See the Canada-wide carrot planting guide for dates in BC, Quebec, the Prairies, and the Maritimes — plus soil-temperature triggers and the late-season succession rule.
Ontario Carrot Planting Calendar by City — 2026
Carrots are direct sown only — they do not transplant. All dates are for direct sowing outdoors. First sowing is 4–6 weeks before last frost. Last sowing is 70–80 days before first fall frost to ensure harvest before freeze.
| City | Zone | First Sowing | Last Sowing | Succession Interval | Expected Sowings |
|---|---|---|---|---|---|
| Windsor | 7a | Mar 20–Apr 1 | Jul 20 | Every 3 weeks | 5–6 sowings |
| Toronto | 6b | Mar 25–Apr 5 | Jul 15 | Every 3 weeks | 5 sowings |
| Hamilton | 6b/7a | Mar 25–Apr 5 | Jul 15 | Every 3 weeks | 5 sowings |
| London | 6a | Apr 1–10 | Jul 15 | Every 3 weeks | 4–5 sowings |
| Kingston | 5b | Apr 10–20 | Jul 10 | Every 3 weeks | 4 sowings |
| Ottawa | 5a | Apr 15–25 | Jul 10 | Every 3 weeks | 4 sowings |
Succession Planting Schedule — Toronto Example
Succession planting gives you continuous harvests instead of one big glut. Here's what a full Toronto carrot season looks like — adjust first sowing 2–3 weeks later for Ottawa and Kingston.
Best Carrot Varieties for Ontario
Ontario's soils vary dramatically from heavy clay (Ottawa River valley, much of southern Ontario) to sandy loam (areas around London and Norfolk County). Variety selection — especially days to maturity and root shape — affects how well carrots perform in your specific soil type.
🥔 Best for All Ontario Soils (including clay)
🥔 Best for Containers and Raised Beds
🥔 Best for Storage — Toronto, Hamilton, Windsor
These varieties have the days and size to produce well in longer-season southern Ontario cities, and store best through winter.
Ontario Carrot Sow Dates by Region
Carrot sow dates shift 2–3 weeks across Ontario's five zones. The carrot rule is soil at 10°C minimum — carrots will germinate slowly (12–18 days) at cooler temperatures and reliably (7–10 days) above 13°C. Below: realistic first-sow (spring) and last-sow (fall) dates by Ontario region. Fall sowings produce the sweetest, densest roots — frost concentrates sugars dramatically.
| Ontario region | Zone | First spring sow | Last sow for fall harvest | Cities |
|---|---|---|---|---|
| Niagara / Carolinian | 6b/7a | April 15 | Aug 14 | St. Catharines, Niagara Falls, Welland, Leamington, Windsor |
| Southwestern ON | 6a/6b | April 20 | Aug 7 | London, Sarnia, Chatham-Kent, Stratford |
| GTA / Golden Horseshoe | 6a/6b | April 25 | Aug 4 | Toronto, Mississauga, Brampton, Hamilton, Oshawa |
| Central ON / Lake Simcoe | 5a/5b | May 5 | July 25 | Barrie, Orillia, Peterborough, Lindsay, Cobourg |
| Eastern ON / Ottawa Valley | 5a/5b | May 4 | July 23 | Ottawa, Kingston, Belleville, Cornwall, Pembroke |
| Northern ON / Canadian Shield | 3b/4b | May 15–25 | July 5 | Sudbury, North Bay, Sault Ste. Marie, Thunder Bay, Timmins |
Fall-sown carrots can be left in-ground under 30 cm of straw mulch and dug fresh through winter into March in zones 5+ — far better flavour than refrigerated storage.
Common Ontario Carrot Pests & Problems
Carrot rust fly (Psila rosae) — the #1 Ontario carrot pest
Larvae tunnel through carrot roots leaving rust-coloured galleries; fall carrots show damage more than spring carrots because the second-generation flies emerge in August. Control: floating row cover (Reemay or Agribon) from sowing through harvest is the only reliable defence; rotate carrots to a new bed each year (rust fly pupae overwinter in soil where carrots grew); avoid sowing where carrots, parsnips, parsley, celery, or dill grew last year. Companion planting with onions and chives partially disorients the fly. Heaviest pressure in Niagara and the GTA; lighter in Northern Ontario.
Forked or twisted roots
Caused by rocky soil, recent fresh manure, or compacted beds. Control: loosen the bed 30 cm deep before sowing; remove all rocks larger than a marble; use composted (not fresh) manure; choose shorter Nantes-type or Chantenay varieties if your soil is challenging (Mokum, Yaya, Nelson). Raised beds with sifted soil produce the straightest carrots. Avoid sowing where parsnips or carrots grew the previous year — the residual root channels can cause forking.
Small stunted carrots (crowding)
The single most common Ontario carrot failure: gardeners don't thin aggressively enough. Carrots need 5–7 cm spacing for proper root development. Control: thin twice. First at 5 cm tall to one carrot per inch. Second at 10 cm tall to final spacing. The first thinnings are an edible baby carrot bonus. Crowded carrots stay pencil-thin and twisted; thinned carrots are full-size and sweet.
Wireworm and cutworm
Soil-dwelling larvae damage seedlings and tunnel through roots. Worst in beds recently converted from lawn or where green manure was tilled in. Control: beneficial nematodes applied to soil in spring are highly effective; potato slice traps (bury slices to lure wireworms, dig up daily and destroy); 1–2 year rotation away from grass-cover beds. Cutworms are mostly a transplant pest; carrots from seed largely avoid them.
Cracked roots (inconsistent watering)
Caused by drought followed by sudden heavy water uptake — the root expands faster than its skin can grow, causing vertical splits. Control: consistent moisture (2–3 cm/week including rain); mulch heavily once carrots are 10 cm tall to even out moisture; drip irrigation or soaker hose better than overhead. Don't harvest immediately after heavy rain — the cracks visible at the soil surface only show what's happening below.
Ontario Carrot Growing Tips
Germination is the hardest part
Carrot seeds are tiny and slow to germinate — 10–21 days is normal depending on soil temperature. The top 2 cm of soil must stay consistently moist during this entire period. In Ontario's often dry May and June, this means daily watering or covering the seed row with damp burlap until sprouts appear. Once germinated, carrots are easy. The most common failure is the soil drying out during the germination window.
Thinning properly — overcrowding ruins carrots
Thin carrot seedlings to 5–8 cm apart when they are 5 cm tall. This is the step most Ontario gardeners skip — overcrowded carrots stay small and forked. Thin in two stages: first to 2–3 cm when seedlings emerge, then to 5–8 cm two weeks later. Use scissors to cut rather than pull — pulling disturbs neighbouring roots. Thinned seedlings are edible as micro-greens.
Ontario clay soils fork carrots — here's the fix
Much of Ontario has heavy clay soil that causes long carrots to fork around obstacles. Solutions: choose stubby varieties (Chantenay, Paris Market, Thumbelina) that don't need deep penetration; add 20–30 cm of loose compost or raised bed mix to create a deep, stone-free growing medium; or grow in raised beds filled with a 50/50 mix of topsoil and compost. Avoid adding fresh manure to carrot beds — it causes forking and hairy roots.
Leave fall carrots in the ground — frost makes them sweeter
Carrots that mature in cool autumn soil develop significantly higher sugar content as the plant converts starches to sugar in response to cold. Ontario's October frosts are your friend here — a carrot left in the ground through several light frosts (down to about -5°C) will be noticeably sweeter than one harvested in August. Mulch with 20–30 cm of straw before hard freeze to extend harvest into November in Toronto and Hamilton.
Summer sowings — beat the heat
Carrot seeds germinate poorly in soil above 30°C — common in Ontario in July and August. For summer succession sowings, sow in the late afternoon, water thoroughly, and cover the row with a light board or damp burlap for the first week to keep soil cool and moist. Remove the cover as soon as sprouts emerge. This simple trick dramatically improves germination rates for summer carrot sowings.
How Ontario Compares — BC and Quebec
Carrots are grown successfully across Canada. Here's how Ontario's timing and conditions compare to BC and Quebec.
| City | First Sowing | Last Sowing | Sowings/Season | Notes |
|---|---|---|---|---|
| Vancouver, BC | Feb 20–Mar 10 | Aug 1 | 6–7 | Earliest in Canada. Mild, wet spring ideal for germination. |
| Kelowna, BC | Mar 20–Apr 1 | Jul 20 | 5–6 | Hot dry summer — irrigation essential for germination. |
| Toronto, ON | Mar 25–Apr 5 | Jul 15 | 5 | Excellent all-round season. Heavy clay common — choose compact varieties. |
| Ottawa, ON | Apr 15–25 | Jul 10 | 4 | Good season. Hot summers help mid-season growth. |
| Montreal, QC | Apr 15–25 | Jul 10 | 4 | Nearly identical to Ottawa. Zone 5b — same timing. |
| Windsor, ON | Mar 20–Apr 1 | Jul 20 | 5–6 | Best Ontario carrot season — longest window in the province. |
Frequently Asked Questions
When should I plant carrots in Ontario?
4–6 weeks before last frost — much earlier than most vegetables. Toronto and Windsor: late March to early April. Hamilton and London: late March to early April. Kingston: mid-April. Ottawa: mid to late April. Use the frost calculator to find your exact last frost date, then count back 4–6 weeks.
Can I plant carrots before last frost in Ontario?
Yes — carrots are a cool-season crop that goes in weeks before last frost. Carrot seeds germinate in soil as cool as 7°C and seedlings tolerate light frost. The biggest risk is not cold — it's the soil drying out during the 10–21 day germination period. Keep the seed row consistently moist until sprouts appear.
Why are my carrots forking in Ontario?
Forking is caused by obstacles in the soil — rocks, clods, or hard clay — that force the root to split around them. Ontario's heavy clay soils are the main culprit. Fix: choose short varieties (Chantenay, Paris Market), add compost to loosen soil to at least 25 cm depth, and never add fresh manure to carrot beds. Raised beds filled with loose compost-rich mix eliminate forking almost entirely.
How many times can I sow carrots in Ontario?
Toronto and Windsor: 5–6 sowings from late March through mid-July. Ottawa and Kingston: 4 sowings from mid-April through early July. Sow every 3 weeks for continuous harvests. The last sowing should be timed so carrots are ready 70–80 days before your first fall frost to ensure a full harvest before hard freeze.
📖 Related Guides & Calculators
Plan your full Ontario vegetable garden.