When to Plant Brussels Sprouts in Wyoming
Published: April 24, 2026
Wyoming gardeners in Zone 6a have a 31-week growing season for brussels sprout (March 30 to November 1). Wyoming's spring and fall windows both work well for brussels sprout — some gardeners plant both successions for a long harvest. This guide gives exact dates for Wyoming based on your local frost calendar.
Brussels Sprout Planting Dates for Wyoming
| Start seeds indoors | February 23–March 2 |
| Last frost (average) | March 30 |
| Transplant outdoors | June 22–July 2 |
| Expect first harvest | September 10 – September 30 |
| Fall crop start | August 2–12 |
| Fall harvest | October 21 |
| First fall frost (average) | November 1 |
⚠ Brussels sprouts are planted in midsummer for a fall harvest. Count back 90 days from your first fall frost to find the transplant date. Start seeds indoors 4–6 weeks before that date. Flavor improves after frost.
Growing Brussels Sprouts in Wyoming's Climate
Wyoming's moderate Zone 6a climate is well-suited to brussels sprout 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 brussels sprout harvest significantly in Wyoming. 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 brussels sprout pests to watch for in Wyoming include Cabbage Worm and Aphid. 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.
Brussels Sprout Garden Calendar for Wyoming
| Month | Task | Notes |
|---|---|---|
| January | — | Dormant season |
| February | Start seeds indoors | Use grow lights; warm soil to 70–75°F for best germination |
| March | Harden off seedlings | Set seedlings outdoors 1–2 hours daily, increasing gradually |
| April | — | Dormant season |
| May ← | Watch for bolting | Harvest promptly; spring heat arrives quickly |
| June | Transplant outdoors | Soil temp must be 45°F+; nighttime lows above 50°F |
| July | — | Dormant season |
| August | Fall crop planting | Transplant or direct sow for fall harvest before frost |
| September | First harvest window opens | Brussels Sprout begins producing 80–100 days after transplant |
| October | — | Dormant season |
| November | First frost approaches | Harvest remaining brussels sprout; cover plants on frost nights |
| December | — | Dormant season |
Brussels Sprout Growing Tips for Wyoming Gardeners
- •Count back 90 days from first fall frost to find the transplant date — this is the most important Brussels sprout timing rule.
- •Pinch the top of each plant about a month before first frost — this channels energy into sprout formation.
- •Wyoming's moderate climate supports succession planting — sow new transplants or seeds every 3 weeks during spring to extend the harvest window into fall.
- •Harvest sprouts from the bottom up as they reach 1-inch diameter; top sprouts finish last.
Companion Planting for Brussels Sprouts in Wyoming
In Wyoming's moderate climate, planting brussels sprout with Onion and Celery helps deter pests and improve soil. Avoid planting near Tomato and Strawberry, which inhibit brussels sprout growth through root chemistry or shared pest pressure. See the full brussels sprout companion planting guide for the complete list.
Frequently Asked Questions
When should I plant brussels sprout in Wyoming?
In Wyoming (Zone 6a), start brussels sprout seeds indoors around February 23–March 2 and transplant outdoors around June 22–July 2 — 12 weeks after the state's average last frost of March 30.
What is the last frost date in Wyoming?
Wyoming'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 brussels sprout year-round in Wyoming?
brussels sprout is a cool-season crop in Wyoming, 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 brussels sprout varieties grow best in Wyoming?
For Wyoming's Zone 6a, consult a local nursery or extension office for brussels-sprouts variety recommendations.
When do I start brussels sprout seeds indoors in Wyoming?
Start brussels sprout seeds indoors in Wyoming 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.