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When to Plant Amaranth in St. Lawrence County, NY

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.

St. Lawrence County, New York is in USDA Zone 4a. The average last spring frost is May 10 and the first fall frost is October 2, giving you a growing season of approximately 145 days.

At an elevation of 688 feet, St. Lawrence County receives approximately 39.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Amaranth to ensure they mature before fall.

St. Lawrence County, NY (Zone 4a) Short season
145 days
Last Spring Frost May 10
145 growing days
First Fall Frost October 2

St. Lawrence County Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 27 Transplant: May 22 🍅 Harvest: Aug 21 – Oct 9
Recommended (50%) ✗ May not fit
Start indoors: Mar 8 Transplant: May 31 🍅 Harvest: Aug 30 – Oct 18
Safe Start (90%) ✗ May not fit
Start indoors: Mar 24 Transplant: Jun 16 🍅 Harvest: Sep 15 – Nov 3

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 St. Lawrence County

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

Soil pH

Your soil pH (4.9โ€“6.6) is more acidic than Amaranth prefers (6.0โ€“7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in St. Lawrence County is excellent for Amaranth โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.9%). 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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 โ€” 2.7" 0" โ„๏ธ Dormant
Feb โ€” 2.6" 0" โ„๏ธ Dormant
Mar โ€” 3.4" 0" โ„๏ธ Dormant
Apr โ€” 3.1" 0" โ„๏ธ Dormant
May 4.3" 3.8" 0.5" ๐Ÿ’ง Light watering
Jun 4.3" 3.6" 0.7" ๐Ÿ’ง Light watering
Jul 4.3" 4.4" 0" โœ… Rainfall sufficient
Aug 4.3" 3.3" 1" ๐Ÿ’ง Light watering
Sep 4.3" 3.2" 1.1" ๐Ÿ’ง Light watering
Oct 4.3" 2.9" 1.4" ๐Ÿ’ง Light watering
Nov โ€” 2.9" 0" โ„๏ธ Dormant
Dec โ€” 3.1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in St. Lawrence County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,365 GDD — county provides 1,885 GDD Excellent fit

Amaranth Planting Timeline โ€” St. Lawrence County, NY

Amaranth Planting Calendar

Activity When Date Range
Start Indoors March 8 Mar 8 โ€“ Mar 22
Transplant Outdoors May 31 May 31 โ€“ Jun 14
Direct Sow May 24 May 24 โ€“ Jun 14
Harvest August 30 Aug 30 โ€“ Oct 18

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

90โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

145 days in St. Lawrence County

Growing Tips for Amaranth in St. Lawrence County

Direct sow Amaranth outdoors after May 10 in St. Lawrence 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 St. Lawrence County, NY?

St. Lawrence County is in Zone 4a with an average last frost of May 10. Plan your Amaranth planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is St. Lawrence County, NY?

St. Lawrence County, New York is in USDA Hardiness Zone 4a. The average last spring frost is May 10 and first fall frost is October 2.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help St. Lawrence County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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