When to plant Amaranth in Polk County, IA
Plant Amaranth in Polk County from May 9 to May 30 in spring. Polk County sits in USDA Zone 5b, with last frost around May 2 and first frost on October 7.
When to Plant Amaranth in Polk County, IA
Your June planting checklist for Polk County, Iowa
Welcome to June in Zone 5b. These are the moves that will have the biggest impact on your growing season.
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Sow amaranth in trays indoors
You're about 14 weeks out from your last frost — the perfect window to get these germinating indoors.
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.
Polk County, Iowa is in USDA Zone 5b. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.
At an elevation of 1,037 feet, Polk County receives approximately 30.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Amaranth during the growing season.
Polk County Soil Profile
Soil Type
Silt Loam
Soil pH
6-6.8
Drainage
Well Drained
Amaranth 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 Polk County
How your county's soil matches Amaranth's growing requirements.
Soil pH
Your soil pH (6.0–6.8) is within Amaranth's preferred range (6.0–7.5).
Soil Texture
The silt loam soil in Polk County is excellent for Amaranth — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Amaranth.
Organic Matter
Organic matter is excellent (4.7%) — Amaranth will thrive.
How to Plant Amaranth
Amaranth Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.2" | 0" | ❄️ Dormant |
| Mar | — | 2.1" | 0" | ❄️ Dormant |
| Apr | — | 2.6" | 0" | ❄️ Dormant |
| May | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Jun | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Jul | 4.3" | 3.3" | 1" | 💧 Light watering |
| Aug | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Sep | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Oct | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Nov | — | 1.9" | 0" | ❄️ Dormant |
| Dec | — | 1.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Polk 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 Planting Timeline — Polk County, IA
Amaranth Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 7 | Mar 7 – Mar 21 |
| Transplant Outdoors | May 16 | May 16 – May 30 |
| Direct Sow | May 9 | May 9 – May 30 |
| Harvest | August 15 | Aug 15 – Oct 3 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | — |
| 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 5b
📆 Growing Season
158 days in Polk County
Growing Tips for Amaranth in Polk County
Direct sow Amaranth outdoors after May 02 in Polk 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
Check more plant combinations with our Companion Planting Checker →
Amaranth in Other Locations
Frequently Asked Questions
When should I plant Amaranth in Polk County, IA?
Polk County is in Zone 5b 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 Polk County, IA?
Polk County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is May 2 and first fall frost is October 7.
When should I plant Amaranth in Polk County, IA?
In Polk County, IA, plant Amaranth after the last frost (around May 2) and before the first frost (around October 7). Best results when soil holds above 50°F.
What growing zone is Polk County, IA for Amaranth?
Polk County sits in USDA Zone 5b. Amaranth grows reliably in zones 2a through 11b, so it's a good fit here.
Can Amaranth grow in Polk County's climate?
Yes — Amaranth grows well in Polk County's temperate climate. Polk County averages a 158-day frost-free season, with last frost around May 2 and first frost around October 7.
Your Polk County Garden Planner — Free
A 22-page printable planner built for Polk County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.