When to Plant Collard Greens in Maine (2026 Guide)

Collard greens are a robust leafy green that thrive under Maine’s unique growing conditions. Known for their resilience against both heat and cold, these greens can be exceptionally productive when planted correctly. In areas like Portland, the optimal time to get collards started is crucial, as the last spring frost occurs on May 8, allowing for a relatively long growing season.

For those in different hardiness zones throughout Maine, understanding the right timeline for planting collards is essential. In Zone 6a, for example, you can begin to transplant outdoors after April 27, which provides a bit of a head start compared to areas like Augusta. This timing is particularly beneficial as it ensures plants have established root systems before the warm summer months.

Harvesting collard greens reflects the seasonality of Maine's climate, as they can continue to be picked right up until the first fall frost on October 5 in Zone 5b. Their flavor actually improves once frost hits, turning the starches into sugars. Thus, planning your planting schedule allows you to enjoy fresh greens long into the autumn months.

Planting Schedule by USDA Zone in Maine

Zone	Indoor start	Transplant out	Direct sow	Harvest
Zone 5b	Start March 1 – March 15, ~6–8 weeks before May 8	Transplant outdoors from May 9 – May 20, after the last frost	Direct sow from May 9 – June 1	Harvest from September 5 until October 5, the first fall frost
Zone 6a	Start February 20 – March 7, ~6–8 weeks before April 27	Transplant outdoors from April 28 – May 10, after the last frost	Direct sow from May 11 – June 1	Harvest from September 8 until October 8, the first fall frost

Collard Greens Planting Windows in Maine

Indoor start: For Maine, start collard greens indoors from March 1 to March 15 to give them an early advantage.
Transplant outdoors: You can transplant collard greens outdoors in Portland from May 9 to May 20, right after the last frost.
Harvest: Expect to harvest collards from September 5 until October 5, right before the first fall frost.

Common Mistakes Growing Collard Greens in Maine

One common mistake among Maine gardeners is planting collards too late in the spring, risking growth stunted by the last frost on May 8. Ensure to check the local forecast as late spring weather can be unreliable.
Maine's coastal areas can experience unpredictable fog that affects sunlight, leading to leggy plants. Consider location wisely to ensure your collards get ample light, especially in the early stages of growth.
Neglecting to space plants adequately is another frequent issue in Maine’s moist conditions. Proper airflow is essential to avoid diseases, especially as collards grow larger throughout the season.
Gardeners in Maine often forget the importance of soil health. Given the clay soil prevalent in certain regions, it's critical to amend your soil with organic matter before planting to support robust growth.
Finally, many Maine gardeners do not take full advantage of collards' cut-and-come-again nature. They may harvest too aggressively, preventing the plant from regenerating for multiple pickings throughout the months.

Frequently Asked Questions

What if I’m in a cold pocket of Maine?

If you're in a colder pocket, consider starting your collards indoors even earlier. Monitor the nighttime temperatures and be ready to protect young plants until the risk of frost has entirely passed.

Can I still plant collard greens in May?

Yes, you can certainly plant collard greens in May! Just be sure to wait until after the last frost date, which is May 8 in Portland. This gives your plants the best chance to thrive.

How do I prevent diseases in my collards?

To prevent diseases, rotate your crops each year and ensure good airflow around your collards. Additionally, regularly inspect for pests, especially aphids, and treat them promptly to maintain plant health.

What’s the best way to harvest collards?

The best method is to harvest the outer leaves once they reach 10-12 inches long. Remove them gently, working from the outer edge towards the center of the plant for continued growth.

Can collards survive winter in Maine?

Yes, collards can survive winter in Maine with proper protection. Consider mulching around the base to insulate the roots and cover with row covers for extreme cold periods to extend your harvest.