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When to Plant Radicchio in Hamilton County, NY

Hamilton County, New York Zone 4b May

Top priorities for Hamilton County, New York gardeners in May

Your garden in Hamilton County, New York is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost May 20
Avg. first frost September 28
Soil temp (4") 50°F
Watering Low
Pest pressure Low
Daylight 14.5 hrs
  1. Move radicchio into the garden

    Your last frost (May 20) has passed. These warm-season crops can handle outdoor soil now.

  2. Put radicchio 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.

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Radicchio is an Italian chicory with stunning red and white leaves and a pleasantly bitter flavor. It forms tight heads and is used in salads, grilled, or braised.

Hamilton County, New York is in USDA Zone 4b. The average last spring frost is May 20 and the first fall frost is September 28, giving you a growing season of approximately 131 days.

At an elevation of 959 feet, Hamilton County receives approximately 49.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Radicchio to ensure they mature before fall.

Hamilton County, NY (Zone 4b) Short season
131 days
Last Spring Frost May 20
131 growing days
First Fall Frost September 28

Hamilton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (31 days to spare)
Start indoors: Apr 1 Transplant: May 13 🍅 Harvest: Jul 15 – Aug 19
Recommended (50%) ✓ Fits season (33 days to spare)
Start indoors: Apr 8 Transplant: May 20 🍅 Harvest: Jul 22 – Aug 26
Safe Start (90%) ✓ Fits season (33 days to spare)
Start indoors: Apr 19 Transplant: May 31 🍅 Harvest: Aug 2 – Sep 6

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 Hamilton County

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

Soil pH

Your soil pH (5.2–6.2) is more acidic than Radicchio prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Radicchio.

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Radicchio.

How to Plant Radicchio

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 Radicchio

2
successive plantings in your 131-day season

Sow every 6.9 weeks. Last sowing by Jul 10 to harvest before frost.

For a dedicated fall crop, sow by Jul 06.

Plant Water Budget

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

Monthly Watering Guide for Radicchio

Radicchio needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Radicchio Needs Rainfall You Supplement Action
Jan 4" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 3.5" 0" ❄️ Dormant
Apr 4.8" 0" ❄️ Dormant
May 3" 4.1" 0" ✅ Rainfall sufficient
Jun 3" 5" 0" ✅ Rainfall sufficient
Jul 3" 5.1" 0" ✅ Rainfall sufficient
Aug 3" 4.3" 0" ✅ Rainfall sufficient
Sep 3" 4.6" 0" ✅ Rainfall sufficient
Oct 3.9" 0" ❄️ Dormant
Nov 3.7" 0" ❄️ Dormant
Dec 3.4" 0" ❄️ Dormant

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

Radicchio 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.

Radicchio needs ~752 GDD — county provides 1,408 GDD Excellent fit

Radicchio Planting Timeline — Hamilton County, NY

Radicchio Planting Calendar

Activity When Date Range
Start Indoors April 8 Apr 8 – Apr 22
Transplant Outdoors May 20 May 20 – Jun 3
Direct Sow May 13 May 13 – Jun 3
Harvest July 22 Jul 22 – Aug 26
Fall Sowing July 6 Jul 6 – Jul 20

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 4b

📆 Growing Season

131 days in Hamilton County

Growing Tips for Radicchio in Hamilton County

Direct sow Radicchio outdoors after May 20 in Hamilton County when soil has warmed and frost danger has passed.

Common pests for Radicchio in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Start in late summer for fall harvest. The red color develops with cool nights and light frost. Harvest when heads are firm and compact.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radicchio in Hamilton County, NY?

Hamilton County is in Zone 4b with an average last frost of May 20. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hamilton County, NY?

Hamilton County, New York is in USDA Hardiness Zone 4b. The average last spring frost is May 20 and first fall frost is September 28.

🌱

Your Hamilton County Garden Planner — Free

A 24-page printable planner built for Hamilton 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 Hamilton County, NY. Local conditions may vary. Last updated: May 2026.

Sources & credits

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