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When to Plant Scallions in Haakon County, SD

Haakon County, South Dakota Zone 4b May

Haakon County, South Dakota gardeners: here's your May plan

Welcome to May in Zone 4b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 14
Avg. first frost September 28
Soil temp (4") 54°F
Watering High
Pest pressure Low
Daylight 14.6 hrs
  1. Time to transplant scallions

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Put scallions seeds straight in the ground

    Your soil is 54°F — warm enough for these to germinate without babying.

Coming up in June — start thinking about
  • Starting indoors: scallions

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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.

Haakon County, South Dakota is in USDA Zone 4b. The average last spring frost is May 14 and the first fall frost is September 28, giving you a growing season of approximately 137 days.

At an elevation of 1,097 feet, Haakon County receives approximately 22.5 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.

Haakon County, SD (Zone 4b) Short season
137 days
Last Spring Frost May 14
137 growing days
First Fall Frost September 28

Haakon County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (51 days to spare)
Start indoors: Mar 28 Transplant: May 9 🍅 Harvest: Jul 4 – Aug 1
Recommended (50%) ✓ Fits season (53 days to spare)
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: Jul 9 – Aug 6
Safe Start (90%) ✓ Fits season (50 days to spare)
Start indoors: Apr 14 Transplant: May 26 🍅 Harvest: Jul 21 – Aug 18

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 Haakon County

How your county's soil matches Scallions's growing requirements.

Soil pH

Your soil pH (6.5–7.5) overlaps with Scallions's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Haakon County is excellent for Scallions — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Scallions.

Organic Matter

Organic matter is excellent (4.1%) — Scallions will thrive.

How to Plant Scallions

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Scallions

3
successive plantings in your 137-day season

Sow every 5.7 weeks. Last sowing by Jul 20 to harvest before frost.

For a dedicated fall crop, sow by Jul 06.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 893 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 4.3" 2.6" 1.7" 💧 Light watering
Jun 4.3" 1.6" 2.7" 🚿 Regular watering
Jul 4.3" 1.9" 2.4" 🚿 Regular watering
Aug 4.3" 2.3" 2" 💧 Light watering
Sep 4.3" 2" 2.3" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.8" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Haakon 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 needs ~645 GDD — county provides 1,472 GDD Excellent fit

Scallions Planting Timeline — Haakon County, SD

Scallions Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 – Apr 16
Transplant Outdoors May 14 May 14 – May 28
Direct Sow May 7 May 7 – May 28
Harvest July 9 Jul 9 – Aug 6
Fall Sowing July 6 Jul 6 – Jul 20

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June
July Fall Sowing Harvest
August Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

137 days in Haakon County

Growing Tips for Scallions in Haakon County

Direct sow Scallions outdoors after May 14 in Haakon 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.

Haakon County receives only 22" 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

  • Peas
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Scallions in Haakon County, SD?

Haakon County is in Zone 4b with an average last frost of May 14. Plan your Scallions planting based on this frost date — see the calendar above for exact timing.

What planting zone is Haakon County, SD?

Haakon County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 14 and first fall frost is September 28.

🌱

Your Haakon County Garden Planner — Free

A 24-page printable planner built for Haakon County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Haakon County, SD. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.