When to plant Onion in Laurel, DE
Spring Onion in Laurel goes in March 20–April 10, once nighttime temps stop dipping near freezing. A second sowing from August 29 to September 12 extends the harvest into fall.
When to Plant Onion in Laurel, DE
This month in Sussex County, Delaware
Your Sussex County, Delaware garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.
Before July arrives, get these ready
- First harvests: onion
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.
Laurel, Delaware is in USDA Zone 7b. The average last spring frost is April 3 and the first fall frost is November 7, giving you a growing season of approximately 218 days.
At an elevation of 1,090 feet, Sussex County receives approximately 46 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Onion during the growing season.
Laurel Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.5
Drainage
Well Drained
Onion Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Soil Compatibility in Laurel
How your county's soil matches Onion's growing requirements.
Soil pH
Your soil pH (5.6–6.5) overlaps with Onion's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Sussex County is excellent for Onion — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.8%). Annual compost additions will help Onion.
How to Plant Onion
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Onion Water Budget
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 | — | 3.5" | 0" | ❄️ Dormant |
| Feb | — | 3.5" | 0" | ❄️ Dormant |
| Mar | — | 3.9" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| May | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Jul | 4.3" | 5.3" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Sep | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Oct | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Nov | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Dec | — | 3.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Nov in Sussex County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Onion Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Onion Planting Timeline — Laurel, DE
Onion Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 27 | Feb 27 – Mar 13 |
| Transplant Outdoors | April 3 | Apr 3 – Apr 17 |
| Direct Sow | March 20 | Mar 20 – Apr 10 |
| Harvest | July 3 | Jul 3 – Aug 21 |
| Fall Sowing | August 29 | Aug 29 – Sep 12 |
Plant 1" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | — |
| July | Harvest |
| August | Fall Sowing Harvest |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7b
📆 Growing Season
218 days in Sussex County
Growing Tips for Onion in Laurel
Direct sow Onion outdoors after April 03 in Sussex County when soil has warmed and frost danger has passed.
Common pests for Onion in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.
General growing tips
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
When should I plant Onion in Laurel, DE?
In Laurel, DE, plant Onion after the last frost (around April 3) and before the first frost (around November 7). Best results when soil holds above 50°F.
What growing zone is Laurel, DE for Onion?
Laurel sits in USDA Zone 7b. Onion grows reliably in zones 3a through 10b, so it's a good fit here.
Can Onion grow in Laurel's climate?
Yes — Onion grows well in Laurel's temperate climate. Laurel averages a 218-day frost-free season, with last frost around April 3 and first frost around November 7.
Your Sussex County Garden Planner — Free
A 22-page printable planner built for Sussex County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.