When to Plant Bok Choy in Maine (2026 Guide)

Bok choy thrives in Maine’s cool climate, making it a favorite choice for local gardeners. With the median last spring frost date arriving around May 8 in Zone 5b areas like Portland, timing your planting is crucial. This fast-growing crop can often be harvested in as little as 30 days, provided conditions are right and the danger of late frosts is avoided.

To achieve the best flavor and quality, many Maine gardeners find that the late summer and fall months are ideal for growing bok choy. With a first fall frost expected around October 5 in Portland, sowing in mid-summer allows your plants to mature in the cooler days of autumn, avoiding the heat that can lead to bolting. With the right care, you will enjoy a bountiful harvest.

Bok choy is not only versatile in the kitchen but also has unique growing needs. A consistent watering schedule and careful monitoring for pests—especially cabbage worms and aphids—will help ensure your crop stays healthy throughout the growing season. Embracing these practices will allow you to get the most out of your bok choy planting in Maine.

Planting Schedule by USDA Zone in Maine

Zone	Indoor start	Transplant out	Direct sow	Harvest
Zone 5b	Start February 24 – March 10, ~6–8 weeks before May 8	Transplant outdoors May 9 – May 23, after the last frost	Direct sow April 24 – May 8, just before the last frost	Harvest July 1 – August 15, for summer crops; and September 10 – October 1, for fall crops
Zone 6a	Start February 15 – March 1, ~6–8 weeks before April 27	Transplant outdoors April 28 – May 12, after the last frost	Direct sow April 10 – April 27, nearing the last frost	Harvest June 15 – July 30, for summer crops; and September 10 – October 5, for fall crops

Bok Choy Planting Windows in Maine

Indoor start: For a successful spring crop, start bok choy indoors between February 24 and March 10 in Maine.
Transplant outdoors: Transplant your bok choy outdoors between May 9 and May 23 to avoid late spring frosts.
Harvest: You can expect to harvest bok choy from your garden between July 1 and August 15, and again from September 10 to October 1.

Common Mistakes Growing Bok Choy in Maine

One common mistake made by gardeners in Maine is planting bok choy too early in spring. Late frosts can severely damage young plants, leading to disappointment when the harvest comes. Always check your local frost dates before sowing.
Another frequent issue is ignoring the weather. Maine's spring can be unpredictable, with sudden cold snaps or heat waves. Monitoring the temperature can prevent bolting, especially when growing bok choy in the summer months.
Maine’s coastal fog can impact sunlight exposure, leading to leggy plants. Make sure to plant your bok choy in a location where it receives adequate sunlight throughout the day for healthy growth.
Many gardeners forget about the importance of soil moisture. Bok choy prefers consistent moisture, especially in dry spells during Maine’s growing season. Watering in the morning can help prevent fungal diseases due to humidity.
Finally, new gardeners might overlook pest control, especially in Maine where cabbage worms and aphids can be prevalent. Implementing preventative measures like floating row covers can help protect young plants and ensure a thriving crop.

Frequently Asked Questions

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

If you live in a colder pocket of Maine, you might need to start your bok choy indoors earlier or select faster-maturing varieties. Monitor local frost dates closely and consider using row covers to protect against unexpected cold snaps.

Can I still plant bok choy in May?

Yes, you can still plant bok choy in May, especially in warmer areas of Maine like Zone 6a. Just ensure you plant early in the month before the heat sets in, as bok choy prefers cooler temperatures.

How can I tell when bok choy is ready to harvest?

Bok choy is ready to harvest when the heads reach a size of about 4-6 inches across. Harvest before they begin to flower, cutting at the soil level to allow for potential regrowth.

What pests should I watch for with bok choy?

Common pests that affect bok choy include cabbage worms and aphids. Regularly check the undersides of the leaves, as these pests often hide there and can damage the plants if not controlled.

Is it better to grow bok choy in spring or fall?

Many gardeners find success growing bok choy in the fall due to cooler temperatures that enhance flavor and reduce the risk of bolting. However, spring can also be productive if planted early enough.