When to Plant Broccoli in Utah
Published: April 21, 2026
Utah gardeners in Zone 6a have a 31-week growing season for broccoli (March 30 to November 1). Utah's spring and fall windows both work well for broccoli — some gardeners plant both successions for a long harvest. This guide gives exact dates for Utah based on your local frost calendar.
Broccoli Planting Dates for Utah
| Start seeds indoors | February 16–23 |
| Last frost (average) | March 30 |
| Transplant outdoors | March 2–12 |
| Direct sow outdoors | March 2–12 |
| Expect first harvest | May 1 – May 21 |
| Fall crop start | August 23–September 2 |
| Fall harvest | October 22 |
| 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.
Growing Broccoli in Utah's Climate
Utah's moderate Zone 6a climate is well-suited to broccoli 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 broccoli 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 broccoli pests to watch for in Utah include Cabbage Worm and Cabbage Looper. 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.
Broccoli 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 40°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 broccoli; cover plants on frost nights |
| December | — | Dormant season |
Broccoli Growing Tips for Utah Gardeners
- •For spring: start indoors 6 weeks before last frost and transplant outdoors 4 weeks before last frost.
- •For fall: start indoors in summer — count 10 weeks back from your first fall frost date.
- •Utah's moderate climate supports succession planting — sow new transplants or seeds every 3 weeks during spring to extend the harvest window into fall.
- •Harvest heads before any yellow flowers open — once flowers show, flavor declines quickly.
Companion Planting for Broccoli in Utah
In Utah's moderate climate, planting broccoli with Onion and Garlic helps deter pests and improve soil. Avoid planting near Tomato and Pepper, which inhibit broccoli growth through root chemistry or shared pest pressure. See the full broccoli companion planting guide for the complete list.
Broccoli 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 broccoli in Utah?
In Utah (Zone 6a), start broccoli seeds indoors around February 16–23 and transplant outdoors around March 2–12 — 4 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 broccoli year-round in Utah?
broccoli 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 broccoli varieties grow best in Utah?
For Utah's Zone 6a, Waltham 29, Calabrese, and Green Magic perform well across conditions.
When do I start broccoli seeds indoors in Utah?
Start broccoli seeds indoors in Utah around February 16–23, which is 6 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.