Seed trays on a bright windowsill are one of the first signs of spring for a tomato grower, long before the garden thaws. In Newfoundland and Labrador, the sowing window opens in March and runs into April, so the trays have time to fill out before planting.
When Should You Start Tomato Seeds in Newfoundland and Labrador?
Start tomato seeds indoors in March or April, with mid-March to mid-April as the sweet spot. Timing here follows the dates of the nearest comparable climate, so confirm local timing with a garden centre, a garden society or the provincial gardening groups.
| Step | When in Newfoundland and Labrador | Why |
|---|---|---|
| Sow seeds indoors | March to April (mid-March to mid-April) | Seedlings need six to eight weeks indoors before they go out |
| Plant outside | May to June (late May to early June) | The danger of the last frost has to be gone first |
| Harden off | In the one to two weeks before planting | Plants adjust to sun and wind outdoors |
Frost dates vary a lot across a province. At St. John’s, the average last spring frost falls on May 30, which means that in one year out of two frost arrives later. Treat it as the middle of a window, never a safe date. Northern and upland districts, including Labrador, run weeks behind. Potting up into larger containers happens as the seedlings outgrow their first cells, a little before the hardening-off stage.
Newfoundland and Labrador — the year and the numbers
- State
- Newfoundland and Labrador
- Hardiness zones
- 6a
- Last spring frost
- May 30
- First fall frost
- October 17
- Annual rain
- 60 in
- Lawn zone
- cool-season
- Source
- Environment and Climate Change Canada — Canadian Climate Normals 1981-2010, station ST JOHN'S A · St. John's
How to Start Tomatoes from Seed
The gestures are simple, and each one follows the season, from the first sowing to the day the plants go outdoors.
- In March or April, fill clean trays with fresh seed-starting mix, sow the seeds shallowly and keep the mix moist but never soggy.
- Once the seeds are sown, set the trays somewhere warm, because warm mix wakes the seeds faster than a cool room does.
- As soon as seedlings show, move them under bright light, such as a sunny south window or a grow light, so the stems stay short and sturdy.
- When the seedlings outgrow their cells, pot them up into larger containers, handling them by the leaves rather than the fragile stem.
- In the one to two weeks before planting, set the plants outdoors a little longer each day to harden them off.
- In late May to early June, plant out once all danger of frost has passed and the soil has warmed to about 60°F (16°C).
Cold soil stalls a tomato even after the frost is over, so waiting a few extra days at planting time costs the plant very little.
What Happens If You Start Tomato Seeds Too Early
Seedlings sown too early outgrow their trays before the garden is ready for them. They turn tall, thin and floppy, reaching for light, and they can become rootbound in small cells while they wait for the weather to turn.
That wait is real in Newfoundland and Labrador, where planting out happens in late May to early June. Sowing in March or April keeps the plants compact. A stocky seedling with a thick stem settles into the garden faster than a leggy one that has been waiting indoors for weeks.
Where to Get Seed-Starting Advice in Newfoundland and Labrador
Canada has no county extension offices, so local advice comes from the province and from growers nearby. The provincial Department of Fisheries, Forestry and Agriculture is the starting point for questions about growing food in the province.
- Visit a local garden centre in late winter to ask which tomato varieties suit your part of the province and when to sow them.
- Join a local garden society before sowing season, since members know how your district’s spring runs compared with St. John’s.
Common Questions
Do Tomato Seeds Need Heat to Sprout?
Warmth in the seed-starting mix helps seeds germinate, so a warm spot indoors works better than a cool windowsill. Once seedlings appear, they need bright light more than extra heat.
Can You Plant Tomatoes Outside in May in Newfoundland and Labrador?
Late May is the start of the planting window, and it can run into June. Wait until the frost danger is truly over and the soil has warmed, and in cooler districts expect to wait toward the later end of that range.
Which Tomato Varieties Are Worth Trying?
Look for varieties with disease resistance, since many modern tomatoes are bred for it. A local garden centre can point you to the ones that ripen reliably in a short, cool season.