When to Plant Cauliflower in Utah
Published: April 24, 2026
Utah gardeners in Zone 6a have a 31-week growing season for cauliflower (March 30 to November 1). Utah's spring and fall windows both work well for cauliflower — some gardeners plant both successions for a long harvest. This guide gives exact dates for Utah based on your local frost calendar.
Cauliflower Planting Dates for Utah
| Start seeds indoors | February 23–March 2 |
| Last frost (average) | March 30 |
| Transplant outdoors | March 9–19 |
| Expect first harvest | May 3 – June 17 |
| Fall crop start | August 23–September 2 |
| Fall harvest | October 17 |
| First fall frost (average) | November 1 |
Dates above assume Zone 6a, the most common zone in Utah. Gardeners in cooler Ogden (Zone 5b) plant 1–2 weeks later; warmer St. George (Zone 6b) can plant 1–2 weeks earlier.
⚠ Start cauliflower indoors 4–6 weeks before last frost. Transplant 2–4 weeks before last frost. Needs consistent moisture and cool temps — bolts in heat above 75°F.
Growing Cauliflower in Utah's Climate
Utah's moderate Zone 6a climate is well-suited to cauliflower with minimal special accommodation. The standard transplant calendar works as written, and harvest windows line up with what seed packets recommend without adjustment.
Succession planting extends your cauliflower harvest significantly in Utah. A second planting 3 to 4 weeks after the first gives you a backup in case of pest pressure and extends the total harvest window into early fall.
Common cauliflower pests to watch for in Utah include Cabbage Worm and Cabbage Looper. The first line of defense is companion planting: Onion and Celery 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.
Cauliflower Garden Calendar for Utah
| Month | Task | Notes |
|---|---|---|
| January | — | Dormant season |
| February | Start seeds indoors | Use grow lights; warm soil to 70–75°F for best germination |
| March | Transplant outdoors | Soil temp must be 45°F+; nighttime lows above 50°F |
| April | — | Dormant season |
| May ← | Watch for bolting | Harvest promptly; spring heat arrives quickly |
| June | — | Dormant season |
| July | — | Dormant season |
| August | Fall crop planting | Transplant or direct sow for fall harvest before frost |
| September | — | Dormant season |
| October | — | Dormant season |
| November | First frost approaches | Harvest remaining cauliflower; cover plants on frost nights |
| December | — | Dormant season |
Cauliflower Growing Tips for Utah Gardeners
- •Blanch white varieties by tying outer leaves over the head when it reaches egg-size — prevents yellowing from sun exposure.
- •Keep soil evenly moist — drought stress causes small, bitter 'buttoning' heads instead of full curds.
- •Utah's moderate climate supports succession planting — sow new transplants or seeds every 3 weeks during spring to extend the harvest window into fall.
- •Plant fall crops in mid-July to mid-August for October harvest; fall cauliflower is usually larger and sweeter than spring.
Companion Planting for Cauliflower in Utah
In Utah's moderate climate, planting cauliflower with Onion and Celery helps deter pests and improve soil. Avoid planting near Tomato and Strawberry, which inhibit cauliflower growth through root chemistry or shared pest pressure. See the full cauliflower companion planting guide for the complete list.
Cauliflower Planting Dates by City in Utah
Top cities in Utah — select for city-level frost dates and planting calendars.
Frequently Asked Questions
When should I plant cauliflower in Utah?
In Utah (Zone 6a), start cauliflower seeds indoors around February 23–March 2 and transplant outdoors around March 9–19 — 3 weeks before the state's average last frost of March 30.
What is the last frost date in Utah?
Utah's average last frost date is March 30 in the state's most common Zone 6a. 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 cauliflower year-round in Utah?
cauliflower is a cool-season crop in Utah, 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 cauliflower varieties grow best in Utah?
For Utah's Zone 6a, consult a local nursery or extension office for cauliflower variety recommendations.
When do I start cauliflower seeds indoors in Utah?
Start cauliflower seeds indoors in Utah around February 23–March 2, which is 5 weeks before the state's average last frost of March 30. Use grow lights and keep soil temperatures at 70–75°F for fastest germination.