When to Plant Sweet Corn in Fredericton, NB
Published: April 24, 2026 · Updated: April 27, 2026
Direct sow after last frost when soil reaches 60°F. Plant in blocks of at least 4 rows for wind pollination. Succession plant every 2 weeks for continuous harvest.
Fredericton's Canadian Zone 5b (USDA 5a) St. John River valley climate is continental with maritime influence. Warmer summers than coastal New Brunswick, colder winters. 151 frost-free days support a broad range of warm-season vegetables when timed carefully.
Sweet Corn Planting Calendar for Fredericton
Direct sow outdoors: May 17–27
Harvest window: July 21 – August 15
Minimum soil temperature: 16°C (60°F)
Days to harvest: 65–90 days
Sun requirement: Full sun (8+ hours)
⚠ Direct sow corn after last frost when soil reaches 60°F. Plant in blocks of at least 4 rows for pollination. Succession plant every 2 weeks for continuous harvest.
Fredericton Climate Notes
Fredericton's St. John River valley creates a warmer microclimate than surrounding uplands. The city has New Brunswick's most productive growing conditions for warm-season crops. Long daylight hours in June-July produce exceptional tomato and pepper quality.
Growing Tips for Sweet Corn
- Plant in blocks of at least 4 rows × 4 plants, not single rows — corn is wind-pollinated and single rows produce deformed ears.
- Sow successively every 2 weeks until 90 days before first fall frost for continuous harvest through summer.
- Side-dress with nitrogen when plants are knee-high and again at tasseling — corn is an extremely heavy feeder.
- Test for ripeness by puncturing a kernel: clear liquid is under-ripe, milky liquid is perfect, pasty is over-ripe.
Companion Planting in Fredericton
Pair sweet corn with Bush Bean, Pumpkin, Squash, Cucumber for mutual benefit. Avoid planting near Tomato, Celery, which compete with or inhibit sweet corn growth.
Pests and Problems to Watch in Fredericton
The most common pest and disease pressure on sweet corn in Fredericton comes from Corn Earworm, Cutworm, Corn Rootworm, Raccoons. Floating row covers through the first 4–6 weeks after planting block adult pests from laying eggs, and a weekly scouting routine catches infestations before they damage the crop.
Other New Brunswick Cities
Frequently Asked Questions
When do I plant sweet corn in Fredericton?
Fredericton's last spring frost is around May 10. Direct sow May 17–27.
What Canadian hardiness zone is Fredericton?
Fredericton is in Canadian Zone 5b (USDA equivalent 5a). The St. John River valley continental maritime climate delivers 151 frost-free days from May 10 to October 8, which shapes every planting date in the local calendar.
How long is Fredericton's growing season?
Fredericton has 151 frost-free days — from May 10 in spring to October 8 in fall. That is more than enough time to finish a full sweet corn crop (65–90 days to maturity) before the first fall frost.
Can I grow sweet corn in containers in Fredericton?
Yes. Container growing on balconies and decks is practical in Fredericton — choose a 5-gallon or larger dark-coloured container to warm the root zone, use a high-quality potting mix, and water daily during hot summer weather. In milder climates, containers extend both spring and fall windows by several weeks.
What is the first fall frost in Fredericton?
Fredericton's average first fall frost is October 8. Most sweet corn in Fredericton is a single spring-timed planting designed to harvest before the first fall frost.