What to plant this week in Flagstaff, AZ
Flagstaff gardeners are in the final stretch before winter, with October 17 marking your average first frost date. This week is critical for harvesting cold-tolerant crops like garlic and late-maturing squashes while preparing hardy perennials for their dormant cycle.
The next 7 days
Flagstaff, AZGrowing in Flagstaff right now
- Watch for rapid temperature swings between high desert days and cool nights; mulch heavily around tomatoes, peppers, and young seedlings to protect roots from freezing.
- The short growing season means your fall harvest window is tight—prioritize cutting zucchini, pumpkins, and beans today before temperatures drop below 40°F.
- Flagstaff's rocky soil drains quickly in autumn rain; add organic matter now to improve water retention for next spring's planting.
- While frost dates are set by averages, a hard freeze can arrive early this year due to high elevation winds, so bring sensitive containers indoors immediately.
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
- Late-season aphids may still cluster on the undersides of basil and bean leaves; hose them off or use neem oil if populations spike before harvest.
- Slugs and snails thrive in Flagstaff's cool, damp October nights and will target remaining lettuce, spinach, and young transplants.
- Powdery mildew can develop on cucumbers, melons, and squash during the humidity of autumn mornings; improve airflow by staking tall varieties.
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.
Flagstaff gardening questions
3When should I stop harvesting my summer squash and pumpkins?
Stop picking zucchini immediately once nights dip near 40°F to prevent the plant from setting new fruit that might freeze. For winter squashes like butternut or acorn, let them ripen fully on the vine until a hard frost kills the foliage, then harvest them.
Can I still transplant garlic now in Flagstaff?
Yes, this is actually an ideal time to plant softneck and hardneck garlic varieties before the ground freezes. Push cloves directly into well-drained soil about 2 inches deep and water thoroughly to settle roots before the cold sets in.
What should I do with my dahlia tubers after the first frost?
Once the foliage turns brown following the average October 17 frost, dig up your dahlia tubers carefully and brush off excess dirt. Cure them in a cool, dry place for two weeks before storing them in peat moss or vermiculite in a container that stays above freezing all winter.
Other cities in zone 6a
12See the full zone 6a guide → · Plan your Flagstaff garden in SproutGuide →