When to Plant Leeks in Bennett County, SD
Leeks are a mild, sweet allium that produces long white shanks. They are more refined than onions and are a key ingredient in soups, stews, and gratins.
Bennett County, South Dakota is in USDA Zone 4b. The average last spring frost is May 11 and the first fall frost is October 4, giving you a growing season of approximately 146 days.
At an elevation of 1,025 feet, Bennett County receives approximately 24.9 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Leeks to ensure they mature before fall.
Bennett County Soil Profile
Soil Type
Loam
Soil pH
6.2-7.6
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 Bennett County
How your county's soil matches Leeks's growing requirements.
Soil pH
Your soil pH (6.2–7.6) overlaps with Leeks's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in Bennett County is excellent for Leeks — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.3%). Annual compost additions will help Leeks.
How to Plant Leeks
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Plant Water Budget
Water stress score is 10/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Leeks
Leeks needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.
| Month | Leeks Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.1" | 0" | ❄️ Dormant |
| Apr | — | 2.9" | 0" | ❄️ Dormant |
| May | 3.5" | 3.3" | 0.2" | 💧 Light watering |
| Jun | 3.5" | 1.6" | 1.9" | 🚿 Regular watering |
| Jul | 3.5" | 2.2" | 1.3" | 💧 Light watering |
| Aug | 3.5" | 2.5" | 1" | 💧 Light watering |
| Sep | 3.5" | 2.1" | 1.4" | 💧 Light watering |
| Oct | 3.5" | 2" | 1.5" | 💧 Light watering |
| Nov | — | 1.8" | 0" | ❄️ Dormant |
| Dec | — | 1.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Bennett County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Leeks 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.
Leeks Planting Timeline — Bennett County, SD
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 30 | Mar 30 – Apr 13 |
| Transplant Outdoors | May 11 | May 11 – May 25 |
| Direct Sow | May 4 | May 4 – May 25 |
| Harvest | August 10 | Aug 10 – Oct 5 |
| Fall Sowing | July 12 | Jul 12 – Jul 26 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.8"/week · Only during dry spells
📅 Days to Maturity
90–150 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 4b
📆 Growing Season
146 days in Bennett County
Growing Tips for Leeks in Bennett County
Direct sow Leeks outdoors after May 11 in Bennett County when soil has warmed and frost danger has passed.
Your 146.0-day growing season in Bennett County is tight for Leeks (90.0-150.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Leeks 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 10-12 weeks before last frost. Transplant into trenches and hill soil around stems as they grow to increase the white portion. Harvest as needed.
Companion Planting
Good Companions
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Check more plant combinations with our Companion Planting Checker →
Leeks in Other Locations
Frequently Asked Questions
When should I plant Leeks in Bennett County, SD?
Bennett County is in Zone 4b with an average last frost of May 11. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.
What planting zone is Bennett County, SD?
Bennett County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 11 and first fall frost is October 4.
Plan Your Garden with Confidence
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