Climate-based carrot planting guide for London, Ontario
When to Plant Carrots in London: Timing and Maturity Guide
Carrots are usually a comfortable fit in London. The season is generally supportive enough that consistency, sizing, and harvest goals matter more than season pressure.
Typical Planting Window
Use the planting dates below for carrots in London.
Gardeners usually sow outdoors around April 12. Most varieties need about 65–75 days to reach maturity.
Carrots are usually a comfortable fit in London. Gardeners usually get the best results when they use that margin to improve finish quality and uniformity.
Even here, the climate does not guarantee an even finish. The better results still come from steady growth, consistent sizing, and harvesting when the crop is actually ready.
Best local strategy: Sow in the normal window and manage for spacing, even moisture, and harvest size; the season usually gives you room to grow for quality, not just completion.
Can Carrots Mature in London?
Growing degree days measure how much useful warmth typically accumulates during the season. For carrots, this helps estimate whether local heat accumulation is usually enough for the crop to reach maturity on time.
From the usual planting window, London typically provides about 3861 growing degree days for carrots. With a typical crop target of 750, that leaves a heat margin of +3111. That large heat margin means season length is usually not the limiting issue here. The more useful question is how gardeners use that room to improve sizing, finish quality, and harvest timing.
GDD Checkpoints for London
If planting later than usual, this table shows how much growing degree day heat is still available from each point in the season. For carrots, it is most useful for judging how much freedom you still have to plant for quality, finish, and harvest goals as the season moves along.
| Checkpoint | Remaining GDD | Heat margin | Fit vs typical target |
|---|---|---|---|
| Apr 15 | 4051 | +3301 | Comfortable |
| May 1 | 3929 | +3179 | Comfortable |
| May 15 | 3737 | +2987 | Comfortable |
| Jun 1 | 3413 | +2663 | Comfortable |
| Jun 15 | 3079 | +2329 | Comfortable |
| Jul 1 | 2648 | +1898 | Comfortable |
Best Carrot Varieties for London
Most carrot varieties can succeed in London in a typical year. That gives gardeners room to choose for the kind of harvest they want, not just for minimum maturity speed.
Varieties that often fit well here include:
- Amsterdam — quick and well suited where gardeners want a fast early carrot
- Nelson — a reliable early Nantes-type with broad short-season appeal
- Yaya — smooth and quick, with a strong fit for earlier harvest goals
- Bolero — productive and dependable where the season gives enough room
- Danvers 126 — a classic storage-leaning type that benefits from a little more runway
| Variety class | Typical days to maturity | Typical GDD need | Local fit |
|---|---|---|---|
| Very early | 55–60 | 650 | Good fit |
| Early | 60–68 | 750 | Good fit |
| Mid-season | 68–75 | 850 | Good fit |
| Late | 75–80 | 925 | Good fit |
Main risk: The usual setbacks here come from management choices rather than from the season itself.
How Frost Affects Carrots in London
London usually has about 166 frost-free days, with a typical last spring frost around May 3 and a typical first fall frost around October 16.
Carrots are generally somewhat frost tolerant and temperatures below about 28°F ( -2 °C) can slow growth or damage plants.
Carrots are usually tolerant enough of cool conditions that frost dates act more like planning markers than hard limits. In practice, timing and steady early growth matter more than avoiding every light frost.
The most common problems here are not climatic ones. Gardeners usually lose ground through timing, uneven growth, or letting the crop move past its best stage.
In London, carrots usually have a solid seasonal margin when planted around April 26. Local gardens do not all warm and cool at the same pace. The warmest garden spots are usually south-facing walls, sheltered gardens, raised beds, and sunnier urban lots. Cooler spots like low spots, exposed sites, and shadier yards tend to warm up later and usually provide less heat. For carrots, warmer garden spots usually improve early growth and can make timing a little more forgiving.
Related crops
Related crops worth comparing for the same city:
For a broader local overview, see the London planting guide. You can also use the Growing Degree Day Planner to test planting dates and crop timing.