When to Plant Scallions in Codington County, SD
Scallions (green onions) are mild-flavored alliums harvested for their slender green tops and white bases. They are quick-growing and perfect for succession planting.
Codington County, South Dakota is in USDA Zone 4a. The average last spring frost is May 3 and the first fall frost is October 6, giving you a growing season of approximately 156 days.
At an elevation of 679 feet, Codington County receives approximately 20.6 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Scallions to ensure they mature before fall.
Codington County Soil Profile
Soil Type
Loam
Soil pH
6.6-7.2
Drainage
Well Drained
Plant 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 Codington County
How your county's soil matches Scallions's growing requirements.
Soil pH
Your soil pH (6.6–7.2) overlaps with Scallions's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in Codington County is excellent for Scallions — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.8%). Annual compost additions will help Scallions.
How to Plant Scallions
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Scallions
Sow every 5.7 weeks. Last sowing by Jul 28 to harvest before frost.
For a dedicated fall crop, sow by Jul 14.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Scallions
Scallions needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Scallions Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 0.6" | 0" | ❄️ Dormant |
| Feb | — | 0.8" | 0" | ❄️ Dormant |
| Mar | — | 1.2" | 0" | ❄️ Dormant |
| Apr | — | 2.1" | 0" | ❄️ Dormant |
| May | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Jun | 4.3" | 3.3" | 1" | 💧 Light watering |
| Jul | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| Aug | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Sep | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Oct | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Nov | — | 0.7" | 0" | ❄️ Dormant |
| Dec | — | 0.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Codington County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Scallions 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.
Scallions Planting Timeline — Codington County, SD
Scallions Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 22 | Mar 22 – Apr 5 |
| Transplant Outdoors | May 3 | May 3 – May 17 |
| Direct Sow | April 26 | Apr 26 – May 17 |
| Harvest | June 28 | Jun 28 – Jul 26 |
| Fall Sowing | July 14 | Jul 14 – Jul 28 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Fall Sowing Harvest |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
50–70 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 4a
📆 Growing Season
156 days in Codington County
Growing Tips for Scallions in Codington County
Direct sow Scallions outdoors after May 03 in Codington County when soil has warmed and frost danger has passed.
Common pests for Scallions in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.
Codington County receives only 21" of rain annually. Scallions needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Direct sow every 3 weeks for continuous harvest. Thin to 1 inch apart or grow in clusters. Harvest when pencil-thick by pulling or cutting at soil level.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Scallions in Other Locations
Frequently Asked Questions
When should I plant Scallions in Codington County, SD?
Codington County is in Zone 4a with an average last frost of May 3. Plan your Scallions planting based on this frost date — see the calendar above for exact timing.
What planting zone is Codington County, SD?
Codington County, South Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 3 and first fall frost is October 6.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Codington County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.