Every September, the same question lands in my inbox: when do you plant bulbs in Ontario? The honest answer is that it depends on where you live. A gardener in Windsor and a gardener in Thunder Bay are working with two very different autumns.
The short version: plant spring bulbs in Ontario from late September through early November, once the soil has cooled to about 15°C or lower. Start earlier in the north, finish later in the south, and plant summer bulbs after the last spring frost. Below, I’ll walk you through the exact timing for your part of the province.
Why Timing Matters So Much
Bulbs aren’t seeds. You can’t tuck them in whenever you happen to be in the garden. They run on a schedule, and Ontario’s climate is unforgiving about it.
Spring bloomers like tulips and daffodils need two things from fall. First, several weeks of cool soil to grow roots. Second, a long stretch of cold, roughly 12 to 16 weeks, to trigger flowering. Both happen naturally if you plant on time.
Plant too early, into warm soil, and bulbs may push up leaves that winter then damages. Plant too late, after the ground freezes, and the roots never get going. Either way, you’ve wasted a season and a bag of bulbs.
Ontario stretches from about hardiness zone 2 in the far north to zone 7 in the far south, so the calendar alone can’t be your guide. Soil temperature is a much better one.
The Soil Temperature Rule I Use
Wait until the soil, about 6 inches down, has cooled to roughly 15°C (60°F) or lower and isn’t frozen. A soil thermometer takes the guesswork out. Push it in first thing in the morning, when the reading is at its coolest.
Air temperature fools people. A crisp September morning doesn’t mean the ground is ready. Soil holds onto summer’s heat much longer than the air does.
When to Plant Fall Bulbs in Ontario: By Region
Here’s how I’d think about it, region by region. These windows are guides, not laws. A warm autumn pushes them later, and a cold snap pulls them earlier.
| Region | Approx. zone | Ideal planting window |
|---|---|---|
| Northern Ontario (Thunder Bay, Sudbury, Timmins) | 2 to 4 | Mid-September to early October |
| Central and Eastern Ontario (Barrie, Peterborough, Ottawa, Kingston) | 4 to 6 | Late September to late October |
| Greater Toronto Area and Hamilton | 6 to 7 | Mid-October to early or mid-November |
| Southwestern Ontario (London, Sarnia) | 6 | Early October to early November |
| Windsor and the Niagara region | 6 to 7 | Mid-October to mid-November |
Fall Bulb Planting in Northern Ontario: Timing and Soil Temperature
If you garden in Thunder Bay, Sudbury or Timmins, your window opens earlier and closes faster. The first fall frost can arrive in mid to late September, so I’d aim to plant from mid-September through early October, as soon as the soil drops to about 15°C or lower.
Because winters are harsh, choose your bulbs carefully. Daffodils are hardy to about zone 3 or 4, and crocuses, Siberian squill and glory-of-the-snow are all dependable in the north. Species tulips are tougher than the big hybrids. After the ground starts to freeze, cover your beds with 10 to 15 cm of straw or shredded leaves.
When to Plant Bulbs in Toronto
Toronto’s lake-moderated climate gives you a long, mild fall. Sources disagree on the average first frost, anywhere from mid-October to early November, so I lean on soil temperature. For most Toronto yards, mid-October through early November is the sweet spot. If you plant tulips, the later end of that window is a good choice.
Ottawa and Eastern Ontario: Is Late October Too Late?
People ask me this constantly: is late October too late to plant bulbs in eastern Ontario? Not at all, as long as the ground isn’t frozen. Ottawa’s average first frost falls in early October, so the soil cools quickly, and the best window is roughly late September through late October. But bulbs can go in later if you can still get a trowel into the ground.
Southeastern Ontario, around Kingston and the St. Lawrence, follows a similar pattern. If you’re wondering whether it’s okay to plant tulips there today, on a warm late-September day I’d wait. Tulips are one of the later bulbs to go in, and October is a better bet.
Southwestern Ontario: London, Windsor and Sarnia
If you’re asking when you plant bulbs in southwestern Ontario, the answer runs from early October in London, where the first frost averages in the first ten days of the month, to late October and November around Windsor. Southwestern Ontario also has some of the mildest winters in the province, so you have more room to plant late.
What About Autumn Crocuses in Southwestern Ontario?
This one catches people out, because “autumn crocus” is a different plant on a different schedule. It’s Colchicum, and it blooms in fall, in September and October. That means it’s planted in late summer, in August or early September, right after you get the corms. If you wait, they often flower in the box.
If you find some now, at the end of September, plant them straight away in a sunny, well-drained spot, roughly 10 to 15 cm deep. They may bloom late this year, or next fall. Colchicums are usually rated hardy in zones 4 or 5 to 7, so they suit southwestern Ontario well. Just remember every part of the plant is toxic, so keep them away from pets and kids, and don’t confuse them with the true saffron crocus.
Can You Plant Bulbs Today? It Depends on Where You Live
Today is September 21, so here’s my honest take by region:
- Northern Ontario: yes, this is prime time. Get your bulbs in soon.
- Central and Eastern Ontario: you can start with small bulbs, but the main window is coming up.
- Toronto, Hamilton, London, Windsor and Niagara: it’s early. Buy now, store them cool and dry, and plant in October when the soil cools.
When Do Fall Bulbs Show Up in Ontario Stores?
Most garden centres start stocking spring bulbs in late August or early September, though it varies from store to store. I always suggest buying early, even if you’re not planting for weeks. The best varieties sell out first. Check that bulbs are firm, not soft or mouldy, and keep them in a cool, dry, airy spot until planting day.
Fall-Planted Bulbs: A Type-by-Type Guide
Here are the classic Ontario spring bloomers, with depth and spacing so you can plant with confidence.
Tulips
Tulips need a good long chill to bloom reliably, and Ontario delivers it. Plant them 15 to 20 cm deep, pointed end up, about 10 to 15 cm apart. Deeper planting protects them from freeze-thaw and helps them come back for more than one year. Darwin Hybrids are dependable for big, showy flowers, and species tulips tend to persist even longer.
Daffodils and Narcissus
Daffodils are the most forgiving bulb you can plant. Squirrels and deer leave them alone because the plant is toxic, and they multiply year after year. Plant them about 15 cm deep and 10 to 15 cm apart, on roughly the same schedule as tulips. If you’re in the south and want the details, I’ve written a full guide on when to plant narcissus in southern Ontario
Crocuses (Spring-Blooming)
These are the early birds, often poking up through snow in March. Plant them 8 to 10 cm deep in clusters of 10 or more. Squirrels love crocus bulbs, so cover new plantings with chicken wire before you mulch, and take it off in spring.
Hyacinths
Hyacinths have the strongest fragrance of any spring bulb. Plant them about 15 cm deep in well-drained soil. In zones 3 and 4, add 10 cm of mulch for protection. Their flower spikes tend to shrink in later years, so many Ontario gardeners replant fresh ones each fall.
Alliums
Alliums bloom in late spring and carry on into early summer, bridging the gap between spring bulbs and summer perennials. Plant them 10 to 20 cm deep depending on size. Giant varieties like Globemaster and Gladiator can reach about a metre tall and make a dramatic focal point.
Fall Planting Timing for Perennials, Trees and Bulbs
While you’re out there with the trowel, bulbs aren’t the only thing worth planting in fall. If you’ve been wondering whether you can plant anything in the fall in Ontario, the answer is yes. A handy rule I use: perennials, shrubs, trees and vines can go in up to about six weeks before the ground freezes, while bulbs follow the soil temperature rule above. Keep new plantings watered until the ground freezes. I cover this in more detail in my guide on planting in fall in Ontario
Spring-Planted Bulbs: The Summer Bloomers
Now for the other group. Dahlias, gladiolus, cannas, tuberous begonias and elephant ears are tender. They come from warm climates, so they can’t overwinter in Ontario soil and need to go in after the last frost.
So can you plant summer-flowering bulbs now in Ontario? For these, no. Wait until spring. (Hardy summer bloomers like true lilies are the exception, and they do go in during fall.) I’ve written up the full answer in my guide to summer bulbs in fall
Outdoor planting usually runs from mid-May through early June, and many gardeners wait until after Victoria Day weekend, which is the Monday before May 25.
| Bulb | Plant outdoors | Lift in fall? |
|---|---|---|
| Dahlias | Mid to late May | Yes, after frost blackens the foliage |
| Gladiolus | Mid-May (stagger every 2 weeks) | Yes, when foliage yellows or after frost |
| Cannas | Late May to early June | Yes, after frost kills the foliage |
| Tuberous begonias | Late May (start indoors in Feb or March) | Yes, before a hard frost |
| Elephant ears | Late May to early June | Yes, after frost kills the foliage |
Dahlias
If I could grow only one summer bulb in Ontario, it would be the dahlia. It blooms from July right up to frost. Plant tubers horizontally, 10 to 15 cm deep, with the eye facing up, and stake tall varieties at planting time so you don’t disturb the roots later.
Gladiolus
Gladiolus needs roughly 60 to 90 days from planting to bloom. For flowers all summer, plant a new batch every two weeks from mid-May into June. Watch for thrips, which cause silvery streaks on the leaves, and treat early with insecticidal soap.
Cannas
Cannas grow fast and look tropical. Plant the rhizomes 5 to 8 cm deep after all frost risk has passed, which in southern Ontario usually means around Victoria Day or later.
Starting Tender Bulbs Indoors
Ontario’s growing season is short, so I like to give tender bulbs a head start indoors, about 4 to 6 weeks before they go outside:
- Dahlias: start in March or early April in barely moist soil at about 18 to 21°C.
- Begonias: start in February or March, pressing tubers into moist peat with the hollow side up.
- Cannas: start in April, and soak the rhizomes overnight in warm water before potting.
Ontario Frost Dates for Bulb Planting
Frost dates are averages, and different sources give slightly different numbers, especially for big cities where the airport and the downtown core run a few degrees apart. Use these as a starting point, and trust your soil thermometer.
| City | Typical last spring frost | Typical first fall frost |
|---|---|---|
| Thunder Bay | Early June | Mid-September |
| Sudbury | Mid-May | Late September |
| Ottawa | Early May | Early October |
| London | Early to mid-May | Early October |
| Hamilton | Early May | Mid-October |
| Toronto | Late April to mid-May | Late October to early November |
| Windsor | Mid to late April | Mid to late October |
When to Dig Up Bulbs in Ontario
This is another question I hear a lot, and the answer depends on the type of bulb.
Tender summer bulbs (dahlias, gladiolus, cannas, begonias, elephant ears): dig them up in fall. The best moment is after a frost has blackened the foliage but before the ground freezes. Begonias are more delicate and can come out a bit earlier. If a hard frost threatens before you’re ready, cover the plants for a few nights.
Hardy spring bulbs (tulips, daffodils, crocuses, alliums): leave them in the ground. They’re built for Ontario winters. The only reason to lift them is to divide overcrowded clumps, and the time for that is after the foliage has died back naturally in early summer.
How to Dig and Store Summer Bulbs
- Wait for frost to blacken the foliage, but dig before the ground freezes.
- Cut stems back to about 10 to 15 cm.
- Loosen the soil a few inches out from the plant and lift gently. Damaged tubers rot in storage.
- Shake off loose soil and let them cure. Dahlias, cannas and begonias need a few days, while gladiolus corms need about three weeks, and shouldn’t be washed.
- Pack in dry peat moss, vermiculite or shredded newspaper in a box or mesh bag.
- Store somewhere cool and frost-free, around 5 to 10°C. An unheated basement works well. Avoid a garage or attic where they might freeze.
- Check every month or so, and toss anything that shrivels or rots.
Label everything when you dig. By March, dahlia tubers from different varieties look identical.
Soil Preparation Before You Plant
The number one killer of bulbs in Ontario isn’t cold. It’s wet. Bulbs sitting in soggy soil rot within weeks.
Test your drainage before you plant. Dig a hole about 30 cm deep, fill it with water, and see how long it takes to soak away. If it drains within a couple of hours, you’re fine. If water sits much longer, fix the drainage first.
Clay is common across much of Ontario, and it holds too much moisture. Work in generous compost and some coarse grit, or plant in a raised bed with a loam and compost mix. A small handful of coarse sand under each bulb also helps water drain away from the base.
Common Mistakes Ontario Gardeners Make
- Planting too shallow. Shallow bulbs heave out of the ground during freeze-thaw cycles. Stick to the depth guidelines.
- Cutting foliage too soon. After bloom, leave the leaves until they turn yellow. They feed the bulb for next year.
- Planting in deep shade. Most bulbs want at least six hours of sun during the growing season.
- Buying small bulbs. Bigger, firmer bulbs give bigger flowers. Skip any that are soft or mouldy.
- Skipping winter mulch in Northern Ontario. In zones 3 and 4, add 10 to 15 cm of straw or shredded bark after the ground freezes.
- Planting summer bulbs too early. One frosty night in May can wipe out a whole planting of dahlias or cannas.
Month-by-Month Bulb Calendar for Ontario
| Month | What to do |
|---|---|
| February | Start tuberous begonias indoors |
| March | Start dahlias indoors, order bulbs |
| April | Spring bulbs emerge, remove mulch in the north, prepare beds, start cannas indoors |
| May (after Victoria Day) | Plant dahlias, gladiolus and cannas outdoors in southern Ontario |
| Late May to early June | Plant summer bulbs across the province |
| August | Plant autumn crocus (Colchicum) as soon as you get them |
| Late August to September | Buy fall bulbs. Plant in Northern Ontario. Dig gladiolus corms as foliage yellows |
| October | Plant tulips, daffodils, crocuses and alliums across most of Ontario. Dig dahlias and cannas after frost |
| November | Last chance to plant in southern Ontario, until the ground freezes. Mulch beds |
| December to February | Check stored summer bulbs monthly for rot |
Best Bulbs by Ontario Region
Northern Ontario (zones 2 to 4):
- Siberian squill, which naturalizes readily and is very cold-hardy
- Species tulips, more cold-tolerant than most hybrids
- Daffodils, which return reliably year after year
- Crocuses, among the hardiest bulbs you can buy
- Glory-of-the-snow (Chionodoxa), which blooms while snow is still around
Southern Ontario (zones 6 to 7):
- Dahlias, which make the most of the longer season
- Giant alliums, happy in well-drained soil
- Camassia, a hardy bulb that tolerates moist soil
- Dutch iris, which benefit from the longer season
- Cannas, which love the extra warmth and frost-free days
Quick Answers
When do you plant spring bulbs in Ontario?
From mid-September in the north to mid-November in the far south, once soil temperature falls to about 15°C or lower and before the ground freezes.
Is late October too late to plant bulbs in Ontario?
No. Late October is fine in most of southern and eastern Ontario, as long as the soil isn’t frozen. Even in November you can still plant if you can dig.
When should I plant tulips in Ontario?
October in most of the province, and into early November in the south. They’re one of the later bulbs to go in.
When should I plant bulbs in Ottawa?
Late September through late October works well. The first frost typically arrives in early October, so don’t wait too long.
When should I plant bulbs in London, Ontario?
Early October to early November. Daffodils and small bulbs first, tulips a little later.
When can I plant autumn crocuses in southwestern Ontario?
August to early September, right after you get them. If you find them later, plant them straight away.
When do I dig up bulbs in Ontario?
Tender summer bulbs come up after frost blackens the foliage, before the ground freezes. Hardy spring bulbs stay put.
The Bottom Line
If you remember one thing, make it this: let the soil tell you when to plant, not the calendar. Fall bulbs go in when the soil is cool but not frozen. Summer bulbs go in after the last frost. Two short windows each year, October and late May, and you’ll have colour for months.
If you’re new to this, start with a few dependable bulbs. Darwin Hybrid tulips, Carlton daffodils and Bishop of Llandaff dahlias are widely grown favourites. Get one good season under your belt, then expand.
What are you planting this fall, and where in Ontario are you gardening? Tell me in the comments, and I’ll help you pin down the timing.
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