What to plant this week in Flagstaff, AZ
With last frost still lingering until late April, Flagstaff gardeners should keep cool-season crops like potatoes and garlic in the ground while protecting emerging heat-lovers from unexpected chill. This week marks a critical transition where you can finally harvest your winter squash stores but must wait for mid-April before moving tomatoes or peppers outdoors.
The next 7 days
Flagstaff, AZGrowing in Flagstaff right now
- Flagstaff's high elevation means temperatures drop rapidly after sunset, so use row covers on tender transplants like basil and edamame to prevent frost damage even when daytime temps hit the 60s. The thin soil here drains quickly but can dry out fast in summer rain; mulch heavily around water-intensive crops like cucumbers and pumpkins to retain moisture between downpours.
- Take advantage of the short growing season by focusing on fast-maturing varieties of bush beans, sweet corn, and zucchini that will ripen before the October 17 frost date cuts the season short. Avoid starting heirloom seedlings indoors now as the soil remains too cold for reliable germination; instead, sow direct seeds only once the ground warms above 50°F in late spring.
- Be mindful of heavy snowpack runoff in early spring which can cause temporary waterlogging near drainage ditches and riverbanks; adjust planting schedules slightly north or east of these areas to avoid root rot on perennials like dahlias and fennel.
Sow this week
No direct sowing windows open this week.
Transplant this week
Nothing is due to go out this week.
Harvest soon
45 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
- Leek
- Lima Bean
- Lisianthus (Prairie Gentian)
- Loofah (Luffa)
- Malabar Spinach
- Nasturtium
- Okra
- Ornamental Sweet Potato Vine
- Parsnip
- Pole Bean
- Potato
- 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 tips of basil and okra to encourage bushier growth rather than flowering too early.
- Add a thin layer of straw or shredded leaves around heavy feeders like pumpkins and squash to retain moisture.
Pest & disease watch
- Spider mites are returning quickly as temperatures climb into the 70s, attacking stressed basil, cosmos, and zinnia plants in full sun.
- Cutworms remain active in cooler microclimates near the timberline, targeting young bean and corn seedlings planted on south-facing slopes.
- Late-season slugs thrive in Flagstaff's cool nights and damp springs, devouring low-growing nasturtiums, parsley, and leeks before they bolt.
Watering this week
Provide about 1 to 2 inches of water per week, applying it deeply in the morning to reduce evaporation and disease risk.
Harvest zucchini and summer squash early in the day when they are most tender and flavorful for your table.
Flagstaff gardening questions
3Can I plant my tomato seeds indoors now for a mid-summer harvest?
No, wait until the last frost date of April 21 passes before moving tomatoes outside; starting them too early risks killing the plants with our high-elevation frosts that can drop to -10°F.
Which crops from my winter harvest should I store versus replant immediately?
Keep your harvested winter squash and pumpkins in a cool, dark place for months, while you can immediately replant garlic cloves or parsnips if they were missed during the last planting window before soil warmth peaked.
How do I protect my edamame from the sudden temperature swings typical of Flagstaff?
Cover young edamame plants with floating row covers at night when temperatures dip below 50°F, and remove them by late afternoon to allow pollination during warmer daylight hours.
Other cities in zone 6a
12See the full zone 6a guide → · Plan your Flagstaff garden in SproutGuide →