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When to Plant Green Beans in St. Lawrence County, NY

Green beans are a warm-season staple available as bush or pole types. Bush beans produce a concentrated harvest while pole beans provide a longer picking season.

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 Green Beans 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) ✓ Fits season (38 days to spare)
Transplant: May 1 🍅 Harvest: Jun 26 – Aug 21
Recommended (50%) ✓ Fits season (33 days to spare)
Transplant: May 10 🍅 Harvest: Jul 5 – Aug 30
Safe Start (90%) ✓ Fits season (33 days to spare)
Transplant: May 26 🍅 Harvest: Jul 21 – Sep 15

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 Green Beans's growing requirements.

Soil pH

Your soil pH (4.9โ€“6.6) is more acidic than Green Beans prefers (6.0โ€“7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Green Beans.

How to Plant Green Beans

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

Succession Planting Green Beans

3
successive plantings in your 145-day season

Sow every 5.7 weeks. Last sowing by Jul 29 to harvest before frost.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Green Beans

Green Beans needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Green Beans 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 3.9" 3.8" 0.1" ๐Ÿ’ง Light watering
Jun 3.9" 3.6" 0.3" ๐Ÿ’ง Light watering
Jul 3.9" 4.4" 0" โœ… Rainfall sufficient
Aug 3.9" 3.3" 0.6" ๐Ÿ’ง Light watering
Sep 3.9" 3.2" 0.7" ๐Ÿ’ง Light watering
Oct 3.9" 2.9" 1" 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.

Green Beans 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.

Green Beans needs ~748 GDD — county provides 1,885 GDD Excellent fit

Green Beans Planting Timeline โ€” St. Lawrence County, NY

Green Beans Planting Calendar

Activity When Date Range
Direct Sow May 24 May 24 โ€“ Jun 14
Harvest July 19 Jul 19 โ€“ Sep 13

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.9"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

50โ€“65 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

145 days in St. Lawrence County

Growing Tips for Green Beans in St. Lawrence County

Direct sow Green Beans outdoors after May 10 in St. Lawrence County when soil has warmed and frost danger has passed.

Common pests for Green Beans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after last frost when soil is warm. Provide sturdy supports for pole varieties. Pick beans regularly when young and tender to encourage continued production.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic
  • Fennel

Check more plant combinations with our Companion Planting Checker →

๐ŸŒพ Save Your Own Green Beans Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Allow pods to dry fully on vine until they rattle.
Storage Store airtight; viable 4 years at 35ยฐF, under 45% humidity.

Avoid harvesting during damp weather. Isolate 25 ft between varieties.

Frequently Asked Questions

When should I plant Green Beans in St. Lawrence County, NY?

St. Lawrence County is in Zone 4a with an average last frost of May 10. Plan your Green Beans 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.