What to plant this week in Portland, ME
With last frost historically around April 21 and current temps hovering near the -10°F winter minimum, Portland gardeners are deep in late summer harvest season. This week is critical for pulling your warm-season crops like watermelons and okra before the October 17 freeze hits, while garlic and shiso thrive in the cool-down.
The next 7 days
Portland, MEGrowing in Portland right now
- Portland's sandy-loam soil drains fast after our spring rains, so add compost to heavy clay patches now to retain moisture for late-maturing zucchini.
- The city's high humidity and coastal proximity create a microclimate perfect for basil but invite fungal issues on crowded tomato vines; space plants wider than seed packets suggest.
- Be prepared for sudden wind gusts from the Atlantic that can snap tall sunflowers or pole beans, so stake them immediately if they haven't been supported yet.
- Take advantage of the short autumn days by sowing hardy greens like malabar spinach and borage now to extend the harvest window before winter sets in.
Sow this week
No direct sowing windows open this week.
Transplant this week
Nothing is due to go out this week.
Harvest soon
41 crops- Basil
- Borage
- Bush Bean
- Cantaloupe
- Celery
- Cleome (Spider Flower)
- Cosmos
- Cowpea (Black-Eyed Pea)
- Cucumber
- Dahlia
- Edamame
- Fennel
- Flour Corn
- French Marigold
- Garden Verbena
- Garlic
- Ghost Pepper (Bhut Jolokia)
- Gourd (Ornamental/Bottle)
- Honeydew Melon
- Lima Bean
- Lisianthus (Prairie Gentian)
- Loofah (Luffa)
- Malabar Spinach
- Nasturtium
- Okra
- Pole Bean
- Pumpkin
- Roselle (Cranberry Hibiscus)
- Scarlet Runner Bean
- Shiso (Japanese Basil)
- Summer Savory
- Sunflower
- Sweet Corn
- Sweet Potato
- Thai Basil
- Vinca (Madagascar Periwinkle)
- Watermelon
- Winter Squash
- Yellow Summer Squash
- Zinnia
- Zucchini
Seasonal tips
- Succession sow bush beans and sweet corn every two weeks for continuous harvests through summer.
- Pinch back the tops of zucchini and squash plants now to encourage more fruit development rather than just vines.
- Cut back dying foliage on basil and borage after heavy harvesting to promote a second, smaller flush of growth.
Pest & disease watch
- Spider mites are exploding on dahlias and cosmos as humidity fluctuates; mist plants early morning or apply insecticidal soap immediately.
- Aphids often swarm the new growth of French marigolds and nasturtiums during this warm stretch, requiring a strong water jet to knock them off.
- Late-season slugs and snails will target tender shiso leaves overnight on any damp, shaded spots in your garden beds.
Watering this week
Water deeply in the early morning to reduce evaporation while supporting heavy fruit production on melons and squash.
Pull any volunteer weeds immediately around your transplants like edamame and fennel before they compete for nutrients.
Portland gardening questions
3Is it safe to transplant sweet corn or beans right now?
No, do not start new transplants; the risk of frost before October 17 is too high for cold-started seeds like corn. Focus instead on harvesting your existing pole and bush bean crops that are listed for soon collection.
What should I do with my dahlia tubers this week?
Since dahlias are ready to be lifted, dig them up carefully before the first hard freeze of mid-October to prevent rot in our damp Portland soil. Dry and store the tubers in a cool, dark place with peat moss for winter storage.
Can I still grow garlic from bulbs at this stage?
Absolutely; garlic is listed as harvest soon but also functions well if you plant new cloves now for a spring crop next year. Plant them 2 inches deep in full sun, ensuring they have enough time to establish roots before the winter chill hits.
Other cities in zone 6a
12See the full zone 6a guide → · Plan your Portland garden in SproutGuide →