When to Plant Onions in Maine
In a typical Maine location, start seeds indoors Feb 21 – Mar 7, then transplant outdoors Apr 4 – Apr 18. Across the state, the outdoor planting window starts as early as Mar 28 in Lewiston and as late as Apr 18 in Sanford.
Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings.
Onions Planting Dates by City
| City | Start indoors | Transplant |
|---|---|---|
| Portland | Feb 15 – Mar 1 | Mar 29 – Apr 12 |
| Lewiston | Feb 14 – Feb 28 | Mar 28 – Apr 11 |
| Bangor | Feb 23 – Mar 9 | Apr 6 – Apr 20 |
| West Scarborough | Feb 15 – Mar 1 | Mar 29 – Apr 12 |
| South Portland | Feb 15 – Mar 1 | Mar 29 – Apr 12 |
| South Portland Gardens | Feb 15 – Mar 1 | Mar 29 – Apr 12 |
| Auburn | Feb 14 – Feb 28 | Mar 28 – Apr 11 |
| Biddeford | Feb 28 – Mar 14 | Apr 11 – Apr 25 |
| Sanford | Mar 7 – Mar 21 | Apr 18 – May 2 |
| Saco | Feb 28 – Mar 14 | Apr 11 – Apr 25 |
| Augusta | Feb 16 – Mar 2 | Mar 30 – Apr 13 |
| Westbrook | Feb 15 – Mar 1 | Mar 29 – Apr 12 |
| Waterville | Feb 21 – Mar 7 | Apr 4 – Apr 18 |
| Brunswick | Feb 21 – Mar 7 | Apr 4 – Apr 18 |
| York Beach | Feb 20 – Mar 6 | Apr 3 – Apr 17 |
| Wells Beach Station | Feb 28 – Mar 14 | Apr 11 – Apr 25 |
| Orono | Feb 20 – Mar 6 | Apr 3 – Apr 17 |
| Lisbon | Mar 6 – Mar 20 | Apr 17 – May 1 |
| North Bath | Mar 1 – Mar 15 | Apr 12 – Apr 26 |
| Brewer | Feb 23 – Mar 9 | Apr 6 – Apr 20 |
| Presque Isle | Mar 5 – Mar 19 | Apr 16 – Apr 30 |
Showing the 21 most populous of 21 Maine cities. Dates are estimates from each city's NOAA frost normals and university extension timing guidelines. See all Maine cities.
Frequently Asked Questions
When should I plant onions in Maine?
In a typical Maine location, start seeds indoors Feb 21 – Mar 7, then transplant outdoors Apr 4 – Apr 18. Across the state, the outdoor planting window starts as early as Mar 28 in Lewiston and as late as Apr 18 in Sanford.
When is the last frost in Maine?
The average last spring frost in Maine ranges from April 25 in Lewiston to May 16 in Sanford, based on NOAA 1991–2020 climate normals.
How long do onions take to grow?
Onions typically take 90–120 days from planting to harvest. Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings.
Other Crops in Maine
- Tomatoes
- Peppers
- Eggplant
- Cucumbers
- Zucchini
- Winter Squash
- Pumpkins
- Watermelon
- Cantaloupe
- Corn
- Green Beans
- Peas
- Lettuce
- Spinach
- Kale
- Arugula
- Swiss Chard
- Broccoli
- Cauliflower
- Cabbage
- Brussels Sprouts
- Carrots
- Beets
- Radishes
- Turnips
- Garlic
- Potatoes
- Sweet Potatoes
- Asparagus
- Basil
- Cilantro
- Parsley
- Dill
- Oregano
- Thyme
- Sunflowers
- Zinnias
- Marigolds
- Cosmos
- Nasturtiums
- Dahlias
When to plant onions in other states