Most tomato varieties can ripen before frost in Ontario, but only if their days-to-maturity actually fit the season you have, not the one you assume you have. Environment and Climate Change Canada’s 1981-2010 climate normals put the average last spring frost at Toronto Pearson at April 30 and the average first fall frost at October 16, a gap of roughly five and a half months. Match the days-to-maturity on the seed packet against that window before you buy the plant, not after it’s already hardened off in your garden bed.
What this comes down to in Ontario
At Toronto Pearson, the season between frosts averages about five and a half months, but that April 30 date is a mean, not a promise: in one year out of two, the last frost actually falls later than that. Most southern Ontario gardeners treat mid-May as the practical transplant point, after the worst of that risk has passed, which is why every variety below is timed from a mid-May set-out rather than from the frost date itself. That still leaves room for plenty of tomatoes to ripen with real margin, but it starts to squeeze anything past about 75 days from transplant, especially outside the Toronto area, where cooler counties run behind these figures.
Sakura
Sakura is a 55-day indeterminate cherry tomato, one of the fastest on this list. Set out mid-May, it typically has its first ripe fruit by early July, leaving around 100 days of margin before the October 16 average frost. It also carries resistance to nematodes, tomato mosaic virus and two races of fusarium wilt, useful in a bed with a history of any of those.
Sun Gold
Sun Gold reaches maturity in about 57 days and ripens to a bright golden-orange rather than red. It resists tobacco mosaic virus and one race of fusarium wilt, and its 98 days of margin before frost make it one of the least risky choices on this list for a gardener who wants snacking tomatoes early and often.
Juliet
Juliet is a 60-day grape tomato, smaller and firmer than a slicer, good for roasting whole or splitting into salads. It carries intermediate resistance to both late blight and early blight, two diseases that show up in wet Ontario summers, and its 95 days of margin gives it plenty of room even in a slow year.
Amalfi
Amalfi is a 68-day determinate paste tomato bred for sauce, with a blocky San Marzano-type shape. Its three intermediate resistances (nematodes, late blight, early blight) matter in a humid growing season, and at 87 days of margin before frost, it finishes with room to spare.
Cherokee Purple
Cherokee Purple is a 72-day heirloom slicer, prized for flavour rather than disease resistance, since it carries none of the coded resistances the newer hybrids on this list do. At 83 days of margin, it still comfortably beats the October 16 average frost, but a gardener growing it alongside a disease problem in the bed should expect to manage that problem by hand.
Big Beef Plus
Big Beef Plus matches Cherokee Purple’s 72-day maturity but adds resistance to nematodes, gray leaf spot and tomato mosaic virus. It is the more forgiving choice of the two large-fruited slicers on this list if disease pressure, rather than flavour, is the deciding factor.
Tiren
Tiren is a 75-day paste tomato with resistance to verticillium wilt, tomato mosaic virus and one race of fusarium wilt. Its 80 days of margin is comfortable rather than generous, so it rewards a prompt mid-May transplant more than the shorter-season varieties above do.
San Marzano II
San Marzano II is a 78-day paste tomato, the longest season on this list alongside Celebrity Plus. Its 77 days of margin before the average October 16 frost still gets it home in most years, but it is the variety on this list with the least room for a late spring or a cool summer.
Celebrity Plus
Celebrity Plus is a 78-day determinate slicer with resistance to nematodes, gray leaf spot and tomato mosaic virus. Like San Marzano II, its 77 days of margin is workable but tight, and it is not the variety to plant if your transplants go in later than mid-May for any reason.
| Variety | Days to maturity | Growth habit | Margin before average frost |
|---|---|---|---|
| Sakura | 55 | Indeterminate | 100 days |
| Sun Gold | 57 | Indeterminate | 98 days |
| Juliet | 60 | Indeterminate | 95 days |
| Amalfi | 68 | Determinate | 87 days |
| Cherokee Purple | 72 | Indeterminate | 83 days |
| Big Beef Plus | 72 | Indeterminate | 83 days |
| Tiren | 75 | Indeterminate | 80 days |
| San Marzano II | 78 | Indeterminate | 77 days |
| Celebrity Plus | 78 | Determinate | 77 days |
Working it out for your own garden
The method matters more than any single variety, because it still works if you move, or if a season runs cold. Start from the frost window itself, covered in detail on Tomato Planting Dates in Ontario: Counting Back From Your Frost Window, then count forward using the days-to-maturity printed on the packet or catalogue page. That figure is counted from transplant, not from seed, and it shifts by a week or two either way depending on how warm the summer runs.
A worked example, both ways
Take Sakura, a 55-day tomato. Transplanted in mid-May, as most southern Ontario gardeners do once the frost risk from the April 30 average has largely passed, it reaches maturity in early July. Counting forward from there to the October 16 average first fall frost at Toronto Pearson leaves about 100 days of margin, more than enough to absorb a slow start or a stretch of cool weather.
Now take a hypothetical 95-day heirloom slicer, a length several seed catalogues list for large beefsteak types outside the varieties named above. Transplanted at the same mid-May point, it would not set its first ripe fruit until early to mid-September. Because October 16 is only the average date, in years when frost arrives earlier than that mean, and it does in roughly half of them, that fruit is still on the vine when the first cold night hits. That is where the line sits: past about 80 days from transplant, the margin this region’s frost window allows starts to disappear.
This is also why the choice of variety cannot be separated from the step that comes before it, covered on the main growing tomatoes in Ontario page: a strong, well-hardened transplant set out on time gains you real days, while a stressed or leggy one set out late loses them.
The mistakes this state punishes
The most common mistake is treating April 30 as a safe planting date rather than the midpoint it actually is. Environment and Climate Change Canada’s normals mean frost falls later than April 30 in about half of all years at Toronto Pearson, so a gardener who plants tender transplants right on that date, especially after a run of unseasonably warm days, is gambling on the better half of the odds. Never treat the mean frost date as a guaranteed one, and hold tender transplants until the soil itself has warmed, not just the air.
The second mistake is picking a long-season variety for a short garden. A San Marzano II or a Celebrity Plus, both at 78 days, still finish most years with margin to spare at Toronto Pearson, but a gardener further north or at higher elevation, where the season runs behind these figures, may find that same margin gone. Reading the days-to-maturity as if the whole province shared one climate is the fastest way to end up with a bed of green fruit in October.
A shorter list of smaller errors compounds both of the above:
- Setting out transplants into cold, wet soil right after a warm stretch, which stalls growth for a week or more without killing the plant outright
- Growing only one long-season paste variety instead of pairing it with a 55 to 60-day cherry or grape type as insurance
- Leaving fruit on an indeterminate vine too long in September, when a single cold night can end the season overnight
The fix for all three is the same: build in margin on purpose, rather than discovering how much you had after the season ends.
Checking this against your county
The April 30 and October 16 figures both come from a single station, Toronto Pearson, and Ontario is not one climate. Counties along Georgian Bay, in the Ottawa Valley, or at higher elevation typically see a shorter frost-free season than these figures suggest, while sheltered parts of the Niagara Peninsula and the far southwest often see a longer one. Before locking in a long-season variety, check your own county’s frost record with your local extension office and with the province’s own agriculture resources at Ontario’s Ministry of Agriculture, Food and Rural Affairs, which can point you to the office nearest you.
Common questions
Can I still grow a 90-day tomato in Ontario?
You can, but it leaves very little margin against the average October 16 fall frost at Toronto Pearson once you count forward from a mid-May transplant. A 90-day variety would not ripen until early to mid-September, and in years when frost arrives ahead of that average, the crop is at real risk. None of the varieties in our list run that long, and the longest, San Marzano II and Celebrity Plus at 78 days, are already the tighter end of what this window comfortably supports.
What happens if frost comes before my long-season tomatoes finish?
Green fruit that has reached full size but not colour can still ripen indoors if picked before a hard freeze, though the flavour is never quite the same as vine-ripened fruit. This is exactly why pairing a long-season paste tomato with a 55 to 60-day cherry or grape variety is worth doing, so at least part of the harvest is already in by the time frost risk climbs.
Do disease-resistant varieties ripen any faster than others?
No, disease resistance and days-to-maturity are separate traits and one does not predict the other. Sakura and Cherokee Purple make the point well: Sakura carries resistance to nematodes, tomato mosaic virus and fusarium wilt and matures in 55 days, while Cherokee Purple has none of those resistances and takes 72 days, but the resistance codes have nothing to do with the speed.
Should I pick a variety by days-to-maturity alone?
Days-to-maturity should set the outer limit of what you consider, not the whole decision. Once a variety fits comfortably inside the frost window for your area, disease history in your soil, fruit use (sauce, slicing, snacking) and flavour are all reasonable tie-breakers, since several of the varieties above finish at close to the same point in the season.