When to plant Onion in Middlesex County, CT
Plant Onion in Middlesex County after April 18; the prime window is April 4–April 25. A second sowing from August 17 to August 31 extends the harvest into fall.
When to Plant Onion in Middlesex County, CT
Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.
Middlesex County, Connecticut is in USDA Zone 6b. The average last spring frost is April 18 and the first fall frost is October 26, giving you a growing season of approximately 191 days.
At an elevation of 248 feet, Middlesex County receives approximately 40.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Onion during the growing season.
Middlesex County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.2
Drainage
Well Drained
Monthly Watering Guide for Onion
Onion needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Onion Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.2" | 0" | ❄️ Dormant |
| Feb | — | 3" | 0" | ❄️ Dormant |
| Mar | — | 3.7" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| May | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Jun | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Aug | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Sep | 4.3" | 3" | 1.3" | 💧 Light watering |
| Oct | 4.3" | 3" | 1.3" | 💧 Light watering |
| Nov | — | 2.8" | 0" | ❄️ Dormant |
| Dec | — | 2.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Middlesex County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Onion Planting Timeline — Middlesex County, CT
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 14 | Mar 14 – Mar 28 |
| Transplant Outdoors | April 18 | Apr 18 – May 2 |
| Direct Sow | April 4 | Apr 4 – Apr 25 |
| Harvest | July 18 | Jul 18 – Sep 5 |
| Fall Sowing | August 17 | Aug 17 – Aug 31 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| June | — |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 6b
📆 Growing Season
191 days in Middlesex County
Growing Tips for Middlesex County
Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Onion in Other Locations
Frequently Asked Questions
When should I plant Onion in Middlesex County, CT?
Middlesex County is in Zone 6b with an average last frost of April 18. Plan your Onion planting based on this frost date — see the calendar above for exact timing.
What planting zone is Middlesex County, CT?
Middlesex County, Connecticut is in USDA Hardiness Zone 6b. The average last spring frost is April 18 and first fall frost is October 26.
When should I plant Onion in Middlesex County, CT?
In Middlesex County, CT, plant Onion after the last frost (around April 18) and before the first frost (around October 26). Best results when soil holds above 50°F.
What growing zone is Middlesex County, CT for Onion?
Middlesex County sits in USDA Zone 6b. Onion grows reliably in zones 3a through 10b, so it's a good fit here.
Can Onion grow in Middlesex County's climate?
Yes — Onion grows well in Middlesex County's temperate climate. Middlesex County averages a 191-day frost-free season, with last frost around April 18 and first frost around October 26.
Your Middlesex County Garden Planner — Free
A 22-page printable planner built for Middlesex County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.