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When to Plant Radicchio in Clark County, NV

Clark County, Nevada Zone 9b May

This month in Clark County, Nevada

We've pulled the most time-sensitive tasks for Clark County, Nevada this May and put them front and centre. Tackle them in order.

Avg. last frost February 28
Avg. first frost November 23
Soil temp (4") 70°F
Watering Critical
Pest pressure High
Daylight 13.9 hrs
  1. Pick radicchio

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Get ahead of June
  • First harvests: radicchio

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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.

Clark County, Nevada is in USDA Zone 9b. The average last spring frost is February 28 and the first fall frost is November 23, giving you a growing season of approximately 268 days.

At an elevation of 2,811 feet, Clark County receives approximately 9.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 111°F, so Radicchio may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Radicchio will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Radicchio successfully. Mulch heavily to conserve soil moisture.

Clark County, NV (Zone 9b) Long season
268 days
Last Spring Frost February 28
268 growing days
First Fall Frost November 23

Clark County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.3-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (175 days to spare)
Start indoors: Jan 14 Transplant: Feb 11 🍅 Harvest: Apr 15 – May 20
Recommended (50%) ✓ Fits season (170 days to spare)
Start indoors: Jan 31 Transplant: Feb 28 🍅 Harvest: May 2 – Jun 6
Safe Start (90%) ✓ Fits season (156 days to spare)
Start indoors: Mar 8 Transplant: Apr 5 🍅 Harvest: Jun 7 – Jul 12

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 Clark County

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

Soil pH

Your soil pH (7.3–8.4) is more alkaline than Radicchio prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Clark County warms quickly in spring but drains fast. Radicchio will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Radicchio.

Organic Matter

Organic matter is low (0.8%). Add 2-3 inches of compost before planting Radicchio.

How to Plant Radicchio

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Radicchio

5
successive plantings in your 268-day season

Sow every 6.9 weeks. Last sowing by Sep 04 to harvest before frost.

For a dedicated fall crop, sow by Sep 28.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.2″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 2,197 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

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 0.7" 0" ❄️ Dormant
Feb 3" 0.6" 2.4" 🚿 Regular watering
Mar 3" 0.6" 2.4" 🚿 Regular watering
Apr 3" 0.3" 2.7" 🚿 Regular watering
May 3" 0.2" 2.8" 🚿 Regular watering
Jun 3" 0.3" 2.7" 🚿 Regular watering
Jul 3" 1.5" 1.5" 🚿 Regular watering
Aug 3" 1.9" 1.1" 💧 Light watering
Sep 3" 1.2" 1.8" 🚿 Regular watering
Oct 3" 0.9" 2.1" 🚿 Regular watering
Nov 3" 0.5" 2.5" 🚿 Regular watering
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Clark 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 ~2,328 GDD — county provides 8,944 GDD Excellent fit

Radicchio Planting Timeline — Clark County, NV

Radicchio Planting Calendar

Activity When Date Range
Start Indoors January 31 Jan 31 – Feb 14
Transplant Outdoors February 28 Feb 28 – Mar 14
Direct Sow February 7 Feb 7 – Feb 28
Harvest May 2 May 2 – Jun 6
Fall Sowing September 28 Sep 28 – Oct 12

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · 2-3 times/week

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

268 days in Clark County

Growing Tips for Radicchio in Clark County

Direct sow Radicchio outdoors after February 28 in Clark County when soil has warmed and frost danger has passed.

Sandy soil in Clark County dries quickly — mulch Radicchio with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 111°F in Clark County, provide afternoon shade for Radicchio and water deeply in the morning.

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 Clark County, NV?

Clark County is in Zone 9b with an average last frost of February 28. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clark County, NV?

Clark County, Nevada is in USDA Hardiness Zone 9b. The average last spring frost is February 28 and first fall frost is November 23.

🌱

Your Clark County Garden Planner — Free

A 24-page printable planner built for Clark County (Zone 9b). 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 Clark County, NV. 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.