When to Plant Collard Greens in Arizona
Published: April 24, 2026
Arizona gardeners in Zone 9b enjoy an extended 50-week growing season for collard green. Cool-season crops like collard green do best in fall, winter, and early spring in Arizona — the hot summers bolt these plants before they can be harvested. This guide gives exact dates for Arizona based on your local frost calendar.
Collard Green Planting Dates for Arizona
| Start seeds indoors | December 11–18 |
| Last frost (average) | January 15 |
| Transplant outdoors | December 25–January 4 |
| Direct sow outdoors | December 25–January 4 |
| Expect first harvest | February 23 – March 10 |
| Fall crop start | October 22–November 1 |
| Fall harvest | December 21 |
| First fall frost (average) | December 31 |
Dates above assume Zone 9b, the most common zone in Arizona. Gardeners in cooler San Tan Valley (Zone 7b) plant 1–2 weeks later; warmer Tucson (Zone 9a) can plant 1–2 weeks earlier.
⚠ Direct sow or transplant collard greens 3–4 weeks before last frost. Extremely cold hardy — withstands temps to 15°F. Can be grown as a perennial in Zones 8+. Fall planting produces the best-flavored greens.
Growing Collard Greens in Arizona's Climate
Arizona's warm Zone 9b climate makes collard green a fall, winter, and early spring crop rather than a summer one. The cool-season window runs roughly October through April in Arizona — plant outside this window and the collard green will bolt (send up a flower stalk and turn bitter) before it produces a harvestable crop.
Succession planting stretches the collard green harvest window. Sow small amounts every two weeks from October through February — you will have staggered harvests rather than a single wave to process all at once. Bolt-resistant varieties extend the usable window an extra three to four weeks into warming weather.
Common collard green pests to watch for in Arizona include Cabbage Worm and Aphid. The first line of defense is companion planting: Onion and Garlic planted nearby discourage several of these pests by confusing host-plant identification or repelling adults before they can lay eggs. Weekly garden walks in the early morning catch problems when they're still manageable.
Collard Green Garden Calendar for Arizona
| Month | Task | Notes |
|---|---|---|
| January | Harden off seedlings | Set seedlings outdoors 1–2 hours daily, increasing gradually |
| February | First harvest window opens | Collard Green begins producing 60–75 days after transplant |
| March | — | Off-season |
| April | — | Off-season |
| May ← | Watch for bolting | Harvest promptly; spring heat arrives quickly |
| June | — | Off-season |
| July | — | Off-season |
| August | — | Off-season |
| September | — | Off-season |
| October | Fall crop planting | Transplant or direct sow for fall harvest before frost |
| November | — | Off-season |
| December | Transplant outdoors | Soil temp must be 45°F+; nighttime lows above 50°F |
Collard Green Growing Tips for Arizona Gardeners
- •Harvest outer leaves continuously once plants reach 10 inches — the central growing point produces for months.
- •In Zones 8+ collard greens often overwinter and produce for 2–3 years as a perennial.
- •Arizona's cool-season collard green plants best in October, November, and December for winter and early spring harvest. Spring plantings bolt before producing a harvestable crop.
- •Frost improves flavor dramatically — southern tradition is to wait for the first frost before harvesting.
Companion Planting for Collard Greens in Arizona
In Arizona's warm climate, planting collard green with Onion and Garlic helps deter pests and improve soil. Avoid planting near Tomato and Strawberry, which inhibit collard green growth through root chemistry or shared pest pressure. See the full collard green companion planting guide for the complete list.
Collard Greens Planting Dates by City in Arizona
Top cities in Arizona — select for city-level frost dates and planting calendars.
Frequently Asked Questions
When should I plant collard green in Arizona?
In Arizona (Zone 9b), start collard green seeds indoors around December 11–18 and transplant outdoors around December 25–January 4 — 3 weeks before the state's average last frost of January 15.
What is the last frost date in Arizona?
Arizona's average last frost date is January 15 in the state's most common Zone 9b. Frost dates vary by city — higher elevations and northern counties run 1 to 3 weeks later than the state average. See the city list below for city-level frost dates.
Can I grow collard green year-round in Arizona?
collard green is a cool-season crop in Arizona, with spring and fall windows. Summer heat bolts the plants before they can produce a harvestable crop. Succession planting every 2–3 weeks stretches the harvest window.
What collard green varieties grow best in Arizona?
For Arizona's Zone 9b, consult a local nursery or extension office for collard-greens variety recommendations.
When do I start collard green seeds indoors in Arizona?
Start collard green seeds indoors in Arizona around December 11–18, which is 5 weeks before the state's average last frost of January 15. Use grow lights and keep soil temperatures at 70–75°F for fastest germination.