How to Grow Corn in Canada
On this page
Sow corn in Canada once your soil has warmed to around 16°C (60°F) — it's wind-pollinated, so always sow in a block or grid rather than a single row, to make sure pollen reaches enough plants. A well-grown plant usually gives two cobs, and it's the classic third of the "Three Sisters" planting alongside beans and squash.
The short answer
- Ready in
- 80–95 days
- Site
- 6+ hours of sun, soil pH 5.5–6.8
- Biggest risk
- Damping-off
Core growing advice on this page is checked against named horticultural sources — see References.
Sweet corn (Zea mays)
Also known as: Corn, Indian Corn, Maize · 10 sources cited · Verified
Quick Facts
At a Glance
Growth Stages
| Stage | BBCH | Notes |
|---|---|---|
| Sowing & germination | 0 | Sow 2.5cm deep, 34-45cm apart (20cm for baby corn), in a block or grid pattern rather than rows -- sweetcorn is wind-pollinated and a block ensures pollen reaches enough plants. Germinates in about two weeks at 18-21°C. RHS. |
| Establishment (frost-tender) | 3 | Frost-tender; only plant out once all frost risk has passed, in late May or early June. RHS. |
| Tasseling & cob fill | 6 | Usually produces two cobs per plant, up to 2m tall depending on variety; a well-grown block yields six to nine cobs per square metre. RHS. |
| Harvest | 8 | Test ripeness by piercing a kernel through the peeled-back husk: watery liquid means not ready, creamy liquid means ripe. Harvest by twisting and pulling the cob sharply from the stem, and cook as soon as possible -- the sugars that make it sweet convert quickly to starch once picked. RHS. |
Soil & Growing Conditions
Harvest & Storage
Companion Planting
Can You Save Your Own Sweetcorn Seed?
For most gardeners, yes -- but the reason to think twice isn't legal, it's biological. University of Maryland Extension's guidance on patented seed restrictions is explicit that it applies to commercial growers who've signed a Technology Agreement with a seed company, not home gardeners. The real caution is simpler: most garden sweetcorn is an F1 hybrid, and F1 seed doesn't "breed true" -- plant the kernels you saved and next year's crop is likely to be far less uniform and sweet than what you grew. If you want to save seed reliably, choose an open-pollinated or heirloom variety instead of a hybrid.
Diseases
Pests
Pollination
Wind (abiotic pollination)
RHS: "Sweetcorn is a type of grass, so is wind pollinated". "To maximise pollination, plant in a block or group rather than a long row. That way, each plant is surrounded by several near neighbours, so the chances of successful pollination (resulting in a cob packed with kernels) is much greater, whichever direction the wind blows." "Poor pollination leads to sparsely filled cobs with missing kernels." Growers can also "tap the stems to loosen the pollen" once the tassels open. NOTE the exception: baby corn is sown "in rows not grids" precisely BECAUSE "the female flowers shouldn't be pollinated, otherwise the kernels will start to swell".
Sweetcorn, Plant to Cob
Plan your Corn planting
When to sow and plant Corn depends on your own frost dates. Check the Canada vegetable planting calendar, or the month-by-month guides that cover Corn: May, July, August, September. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.
Growing Sweet corn in another region
Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.
Sources
The full list of 10 sources behind this guide (Clemson Cooperative Extension, Colorado State University, Food Source Information, FAO EcoCrop and others) is in the references of our UK guide to sweetcorn; they describe the plant itself, which is the same wherever it grows.
Frequently Asked Questions
How long does sweetcorn take to grow?
Typically 80–95 days, depending on cultivar and growing conditions.
What soil pH does sweetcorn need?
A pH of about 5.5–6.8. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.
What problems affect sweetcorn?
Our data links 2 diseases and 2 pests to this crop. See the sections above for each one and how to manage it.
Plan next season before the problems start
Short-season growing is arithmetic before it is technique: days to maturity against frost-free days decides what will finish at all. The Canada Garden Planner does that subtraction for your region before you sow.
Get the Canada Garden Planner →Instant PDF download · Written for Canadian growing conditions
How this guide is put together
The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against Canadian hardiness-zone and frost-date data, with provincial agriculture and university extension sources cited directly where one exists for a crop. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.
Vegetable Growing Guides Canada
Related Problem Guides
Last verified 2026-08-06
Where To Go From Here
Take this crop from reading into a written plan for your own beds.
Keep going
Plan the next step
Use the printable SoilCommander planner for your region to turn this guide into sowing dates, bed layouts and weekly garden tasks.