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When to Plant Amaranth in Swift County, MN

Swift County, Minnesota Zone 4b May

May to-do list for Swift County, Minnesota

Here's what deserves your attention in Swift County, Minnesota this month. Everything below is tailored to Zone 4b and timed around your local frost dates.

Avg. last frost May 2
Avg. first frost October 4
Soil temp (4") 56°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Set out amaranth seedlings

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

  2. Sow amaranth where they'll grow

    These tolerate cool soil, so you're not gambling by sowing now.

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Amaranth is an ancient grain crop with edible leaves and seeds, rich in protein and micronutrients. It thrives in warm conditions and is drought-tolerant once established.

Swift County, Minnesota is in USDA Zone 4b. The average last spring frost is May 2 and the first fall frost is October 4, giving you a growing season of approximately 155 days.

At an elevation of 1,212 feet, Swift County receives approximately 35.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Amaranth to ensure they mature before fall.

Swift County, MN (Zone 4b) Moderate season
155 days
Last Spring Frost May 2
155 growing days
First Fall Frost October 4

Swift County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 23 Transplant: May 18 🍅 Harvest: Aug 17 – Oct 5
Recommended (50%) ✗ May not fit
Start indoors: Feb 28 Transplant: May 23 🍅 Harvest: Aug 22 – Oct 10
Safe Start (90%) ✗ May not fit
Start indoors: Mar 13 Transplant: Jun 5 🍅 Harvest: Sep 4 – Oct 23

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 Swift County

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

Soil pH

Your soil pH (6.3–6.7) is within Amaranth's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Swift County is excellent for Amaranth — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Amaranth.

Organic Matter

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

How to Plant Amaranth

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 474 gal / 100 sq ft

Monthly Watering Guide for Amaranth

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

Month Amaranth Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 2.3" 2" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

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

Amaranth 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.

Amaranth needs ~1,286 GDD — county provides 1,898 GDD Excellent fit

Amaranth Planting Timeline — Swift County, MN

Amaranth Planting Calendar

Activity When Date Range
Start Indoors February 28 Feb 28 – Mar 14
Transplant Outdoors May 23 May 23 – Jun 6
Direct Sow May 16 May 16 – Jun 6
Harvest August 22 Aug 22 – Oct 10

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

155 days in Swift County

Growing Tips for Amaranth in Swift County

Direct sow Amaranth outdoors after May 02 in Swift County when soil has warmed and frost danger has passed.

General growing tips

Direct sow after last frost when soil is warm. Thin seedlings to 18 inches apart. Harvest leaves when young and tender; harvest seeds when flower heads begin to dry.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Amaranth in Swift County, MN?

Swift County is in Zone 4b with an average last frost of May 2. Plan your Amaranth planting based on this frost date — see the calendar above for exact timing.

What planting zone is Swift County, MN?

Swift County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is May 2 and first fall frost is October 4.

🌱

Your Swift County Garden Planner — Free

A 24-page printable planner built for Swift 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Swift County, MN. 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.