Last Frost Date Moncton — When Is It Safe to Plant?
Moncton planting guide — Zone 5a, last frost May 15, first frost September 28, ~136-day season. Full calendar with indoor start dates and outdoor transplant dates for 20+ vegetables.
Moncton's last frost date is May 15 — the date that determines your entire planting schedule. First fall frost arrives around September 28, giving Moncton approximately 136 frost-free days in Zone 5a. The Petitcodiac River and Bay of Fundy provide modest moderation; the Acadian coast (Shediac, Cap-Pelé) gets 2–4 extra days, while inland communities (Salisbury, Sussex) run 5–10 days later.
For a deeper dive on Moncton's frost dates — Greater Moncton community-by-community breakdown (Dieppe, Riverview, Shediac, Sackville NB), Acadian coast Bay of Fundy moderation, Tantramar marsh microclimate, and how Moncton compares to Halifax and Fredericton — see the dedicated Last Frost Date Moncton page, or the province-wide New Brunswick last frost dates. Use this guide alongside the seed starting calculator to build your full planting schedule.
Moncton at a glance: Last frost May 15 · First frost Sept 28 · Growing season ~136 days · Hardiness zone 5b. Cool-season crops (peas, spinach, lettuce, kale) start mid-April; brassicas + onions transplant early May; warm-season crops (tomatoes, peppers, beans, cucumbers) after May 25.
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A printable one-page PDF — seed-starting, transplant, direct-sow and harvest dates for 30+ crops, from your local frost dates.
📅 Moncton's Key Frost Dates
Moncton Planting Calendar — Full Table
All dates calculated from Moncton's average last frost of May 15. Start indoors dates count backward from transplant date. Direct sow dates are when it's safe to plant outdoors.
| Vegetable | Start Indoors | Transplant Out | Direct Sow | Days to Harvest |
|---|---|---|---|---|
| 🍅 Tomatoes | Apr 3–17 | May 25–Jun 1 | — | 55–75 days |
| 🌶 Peppers | Mar 20–Apr 3 | May 28–Jun 5 | — | 60–80 days |
| 🥬 Cucumbers | May 1–8 | May 22–30 | May 22–30 | 50–65 days |
| 🎃 Zucchini / Squash | May 1–8 | May 22–30 | May 22–30 | 50–60 days |
| 🥦 Broccoli | Apr 10–24 | May 6–15 | — | 60–80 days |
| 🥭 Cabbage | Apr 3–17 | May 6–15 | — | 70–120 days |
| 🧀 Onions (seed) | Mar 6–20 | May 6–15 | — | 100–120 days |
| 🧀 Onions (sets) | — | — | May 6–15 | 65–75 days |
| 🥕 Carrots | — | — | May 1–Jun 5 | 70–80 days |
| 🫘 Bush Beans | — | — | May 22–Jun 10 | 50–60 days |
| 🌿 Peas | — | — | Apr 20–May 5 | 55–70 days |
| 🥕 Lettuce | Apr 17–May 1 | May 6–15 | Apr 25–Jun 20 | 45–60 days |
| 🍃 Spinach | — | — | Apr 25–May 25 | 40–50 days |
| 🥦 Kale | — | — | Apr 25–May 15 (+ Aug for fall) | 55–75 days |
| 🪒 Radishes | — | — | Apr 20–Jun 15 | 25–35 days |
| 🥔 Potatoes (seed) | — | — | Apr 25–May 15 | 70–100 days |
| 🥦 Garlic (hardneck) | — | — | Oct 1–15 (previous year) | Harvest Jul–Aug |
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Moncton Month-by-Month Planting Tasks
🌚 March
- Start onion seeds indoors (week 2)
- Start pepper seeds indoors (week 3–4)
- Order seed potatoes and tender bedding plants
🌿 April
- Start tomato seeds indoors (early-to-mid month)
- Start broccoli, cabbage, lettuce indoors (mid-month)
- Direct sow peas, radishes, spinach outdoors (late month)
- Prepare beds — compost amendment
🌺 May
- Plant seed potatoes (week 1–3)
- Transplant brassicas, onions, lettuce (week 1–3)
- Direct sow carrots, kale, beets (early month)
- Transplant tomatoes, peppers, cucumbers, zucchini (after May 25)
- Direct sow bush beans (after May 22)
🍅 June
- Finish warm-crop transplants (week 1)
- Direct sow last beans, cucumbers, zucchini (week 1–2)
- Side-dress with compost
- Mulch heavily for moisture retention
☀️ July–August
- Harvest peas, lettuce, radishes, garlic
- Start fall brassicas indoors (July)
- Direct sow fall kale, spinach, lettuce (early August)
- Watch for late blight on tomatoes (Maritime humidity)
🍁 September–October
- Main harvest: tomatoes, peppers, beans, squash (Sept)
- Cover frost-sensitive crops with row cover (late Sept)
- Plant hardneck garlic (Oct 1–15)
- Mulch garlic beds heavily for overwintering
Best Vegetables for Moncton's Climate
Moncton's humid continental climate with Bay of Fundy moderation favours cool-season crops: kale, peas, broccoli, cabbage, spinach, lettuce, and root vegetables (carrots, beets, potatoes). The Tantramar dyked land near Sackville NB is some of the best agricultural land in the Maritimes for cool-season vegetables.
Warm-season crops succeed with proper variety selection. For tomatoes, pick short-season varieties (55–75 days): Bush Beefsteak, Manitoba, Scotia, Glacier. For peppers, choose 60–75 day varieties and start indoors in mid-March. Cucumbers and zucchini thrive in the warm Moncton July–August. Bay of Fundy humidity creates some late blight pressure — stake tomatoes for airflow and avoid overhead watering.
Hardneck garlic planted in mid-October overwinters reliably under Moncton's snow cover and produces excellent heads — the Maritimes are reputed for high-quality garlic production. The Acadian coast and the Memramcook valley have a tradition of garlic farming worth tapping.
Maritime Late Frost Protection
A late frost after May 15 happens roughly 1 year in 5 in Greater Moncton, more often in Salisbury and Sussex (inland). Maritime late frosts are usually -1 to -3°C and arrive with cold Atlantic rain or wet snow rather than the dry radiation frosts of inland Quebec or the Prairies. Keep floating row cover (Reemay, Agribon) on hand until at least May 25 — the Maritime workhorse for spring frost protection. Cloches over individual seedlings on forecast frost nights. Plant tender crops against a south-facing fence or in a Tantramar dyked field for marsh moderation. Watch the 10-day forecast: don't transplant tender crops if nights below 5°C are forecast within 7 days.
📍 Atlantic Canada Garden Resources
Plan Your Moncton Garden Season
Use the frost calculator for your exact postal code — Acadian coast (Shediac) runs 2–4 days earlier than the May 15 Moncton average; inland Sussex runs 5–10 days later.
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Save to PinterestFrequently Asked Questions
When can I plant my garden in Moncton?
Moncton's average last frost date is May 15 — the date that determines your outdoor planting schedule. Cool-season crops (peas, spinach, radishes, lettuce, kale) can go in 4–6 weeks before that — mid-April. Brassicas (broccoli, cabbage, cauliflower) and onions can be transplanted out 2–4 weeks before last frost — early May. Warm-season crops (tomatoes, peppers, beans, cucumbers, squash) wait until after May 15, typically May 25–June 1 to be safe from late frosts.
What is the last frost date in Moncton?
Moncton's average last spring frost is May 15 (Zone 5a). The Acadian coast (Shediac, Cap-Pelé) runs 2–4 days earlier; Sackville NB and Tantramar 13–17 May; inland NB (Salisbury, Sussex Kennebecasis valley) runs 5–10 days later. Always have frost cloth ready and monitor the 14-day forecast before transplanting tender seedlings — see the dedicated Last Frost Date Moncton page for the full 9-community breakdown.
When should I start tomatoes indoors in Moncton?
Start tomato seeds indoors 6–8 weeks before Moncton's last frost date of May 15 — meaning late March to mid-April. Transplant outdoors May 25–June 1 once soil reaches 10°C. Choose blight-tolerant short-season varieties for Moncton's 136-day season: Bush Beefsteak (62 days), Manitoba (60 days), Scotia (58 days), Glacier (55 days). Bay of Fundy humidity creates some late blight pressure — avoid overhead watering and stake plants for airflow.
How long is the growing season in Moncton?
Moncton's growing season runs approximately 136 days — from last frost around May 15 to first fall frost around September 28. This is similar to Montreal (~150 days), shorter than Halifax (~161 days) due to Moncton's more inland position, and notably longer than the Prairies (Calgary ~120 days). The 136-day window allows most 60–80 day vegetable varieties to mature with margin to spare.
What vegetables grow best in Moncton?
Moncton's humid continental climate with Bay of Fundy moderation favours cool-season crops: kale (excellent all season), peas (spring and fall crops), broccoli and cabbage (two crops possible), spinach, lettuce, and root vegetables (carrots, beets, potatoes — the Tantramar dyked land is some of the best agricultural land in the Maritimes). Warm-season crops succeed too with proper variety selection: short-season tomatoes (Manitoba, Scotia), Bush Champion cucumbers, and Black Beauty zucchini all produce reliably. Hardneck garlic planted in October overwinters reliably under snow cover.
What growing zone is Moncton?
Moncton is Zone 5a — comparable to Montreal, Ottawa, and Fredericton. Greater Moncton (Dieppe, Riverview) is also Zone 5a. The Acadian coast (Shediac, Cap-Pelé, Bouctouche) sits in Zone 5b/6a thanks to Northumberland Strait moderation. Sackville NB and Tantramar are Zone 5b with salt-marsh microclimate. Inland NB (Salisbury, Sussex) drops to Zone 5a/5b. Hardy roses, peonies, lilacs, and hostas all thrive in Greater Moncton.
Can I grow tomatoes in Moncton?
Yes — Moncton's 136-day growing season is sufficient for most tomato varieties. Start indoors late March to mid-April, transplant after May 25 in Greater Moncton (June 1–5 inland Sussex and Salisbury). Choose short-season varieties (55–75 days) for reliable maturity before the September 28 first fall frost: Bush Beefsteak, Manitoba, Scotia, Glacier. Plant in the warmest south-facing spot, stake for airflow to reduce late blight pressure from humid Maritime summers.
Has the last frost passed in Moncton?
Moncton's average last frost is May 15 (Zone 5a). If today's date is past May 15 and no frost is forecast in the next 10 days, the last frost has likely passed in the urban core. However, in any given year there is roughly a 15–20% chance of a frost after May 15 — keep frost cloth ready until May 25. Inland gardeners around Salisbury and Sussex should wait until June 1–5 for tender crops.
Is it safe to plant tomatoes outside in Moncton?
Wait until May 25–June 1 to transplant tomatoes outdoors in Greater Moncton, June 1–5 inland (Salisbury, Sussex). Soil should reach 10°C at 5 cm depth. Choose short-season varieties (55–75 days) and stake plants for airflow — Maritime humidity creates late blight pressure from August onward, so airflow + variety selection matters more than fertilizer.
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Your microclimate may sit closer to the next city over. Distances are straight-line.