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When to Plant Mache in Campbell County, SD

Campbell County, South Dakota Zone 4b May

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

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Campbell County, South Dakota.

Avg. last frost May 11
Avg. first frost September 30
Soil temp (4") 49°F
Watering Moderate
Pest pressure Low
Daylight 14.7 hrs
  1. Transplant mache outside

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Put mache seeds straight in the ground

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

To set up a strong June, finish these tasks
  • Starting indoors: mache
  • First harvests: mache

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Mache (corn salad) is a cold-hardy salad green with small, rounded, tender leaves and a mild, nutty flavor. It thrives in cool weather and even overwinters in many climates.

Campbell County, South Dakota is in USDA Zone 4b. The average last spring frost is May 11 and the first fall frost is September 30, giving you a growing season of approximately 142 days.

At an elevation of 830 feet, Campbell County receives approximately 27.1 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Mache to ensure they mature before fall.

Campbell County, SD (Zone 4b) Short season
142 days
Last Spring Frost May 11
142 growing days
First Fall Frost September 30

Campbell 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 (67 days to spare)
Start indoors: Mar 21 Transplant: May 2 🍅 Harvest: Jun 13 – Jul 18
Recommended (50%) ✓ Fits season (65 days to spare)
Start indoors: Mar 30 Transplant: May 11 🍅 Harvest: Jun 22 – Jul 27
Safe Start (90%) ✓ Fits season (67 days to spare)
Start indoors: Apr 7 Transplant: May 19 🍅 Harvest: Jun 30 – Aug 4

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 Campbell County

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

Soil pH

Your soil pH (6.5–7.5) is within Mache's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.8%). Annual compost additions will help Mache.

How to Plant Mache

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 Mache

4
successive plantings in your 142-day season

Sow every 4.6 weeks. Last sowing by Aug 01 to harvest before frost.

For a dedicated fall crop, sow by Jul 08.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 251 gal / 100 sq ft

Monthly Watering Guide for Mache

Mache needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Mache Needs Rainfall You Supplement Action
Jan 1.9" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 2.8" 0" ❄️ Dormant
May 4.3" 2.8" 1.5" 💧 Light watering
Jun 4.3" 2" 2.3" 🚿 Regular watering
Jul 4.3" 2.2" 2.1" 💧 Light watering
Aug 4.3" 2.5" 1.8" 💧 Light watering
Sep 4.3" 2.4" 1.9" 💧 Light watering
Oct 2.5" 0" ❄️ Dormant
Nov 2.1" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Campbell County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Mache 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.

Mache needs ~500 GDD — county provides 1,420 GDD Excellent fit

Mache Planting Timeline — Campbell County, SD

Mache 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 June 22 Jun 22 – Jul 27
Fall Sowing July 8 Jul 8 – Jul 22

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

142 days in Campbell County

Growing Tips for Mache in Campbell County

Direct sow Mache outdoors after May 11 in Campbell County when soil has warmed and frost danger has passed.

General growing tips

Direct sow in early spring or late summer for fall and winter harvest. Seeds need light to germinate so press gently into soil surface. Harvest whole rosettes.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mache in Campbell County, SD?

Campbell County is in Zone 4b with an average last frost of May 11. Plan your Mache planting based on this frost date — see the calendar above for exact timing.

What planting zone is Campbell County, SD?

Campbell County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 11 and first fall frost is September 30.

🌱

Your Campbell County Garden Planner — Free

A 24-page printable planner built for Campbell 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 Campbell 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.