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When to Plant Chives in Riverside County, CA

Riverside County, California Zone 10a May

This month in Riverside County, California

May is a pivotal month for Riverside County, California gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost February 24
Avg. first frost December 4
Soil temp (4") 74°F
Watering Critical
Pest pressure High
Daylight 13.8 hrs
  1. Bring in the chives

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Get ahead of June
  • First harvests: chives

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Chives are a hardy perennial herb with a mild onion flavor and attractive purple pom-pom flowers. They are one of the easiest herbs to grow and maintain.

Riverside County, California is in USDA Zone 10a. The average last spring frost is February 24 and the first fall frost is December 4, giving you a growing season of approximately 283 days.

At an elevation of 1,206 feet, Riverside County receives approximately 15.5 inches of rainfall annually with predominantly loam soil. Summer highs average 102°F, so Chives may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Chives successfully. Mulch heavily to conserve soil moisture.

Riverside County, CA (Zone 10a) Year-round
283 days
Last Spring Frost February 24
283 growing days
First Fall Frost December 4

Riverside County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (156 days to spare)
Transplant: Feb 10 🍅 Harvest: Apr 14 – Jun 23
Recommended (50%) ✓ Fits season (143 days to spare)
Transplant: Mar 3 🍅 Harvest: May 5 – Jul 14
Safe Start (90%) ✓ Fits season (131 days to spare)
Transplant: Mar 29 🍅 Harvest: May 31 – Aug 9

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 Riverside County

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

Soil pH

Your soil pH (6.2–7.8) overlaps with Chives's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Riverside County is excellent for Chives — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Chives.

How to Plant Chives

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Chives

5
successive plantings in your 283-day season

Sow every 6.9 weeks. Last sowing by Sep 05 to harvest before frost.

Plant Water Budget

Plant needs
0.4″/week
Rainfall provides
0.2″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 518 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Chives

Chives needs approximately 0.4 inches of water per week (1.7" per month). Here's how your county's rainfall compares month by month.

Month Chives Needs Rainfall You Supplement Action
Jan 3.5" 0" ❄️ Dormant
Feb 1.7" 3.6" 0" ✅ Rainfall sufficient
Mar 1.7" 2.2" 0" ✅ Rainfall sufficient
Apr 1.7" 1.2" 0.5" 💧 Light watering
May 1.7" 0.4" 1.3" 🚿 Regular watering
Jun 1.7" 0.1" 1.6" 🚿 Regular watering
Jul 1.7" 0" 1.7" 🚿 Regular watering
Aug 1.7" 0" 1.7" 🚿 Regular watering
Sep 1.7" 0.2" 1.5" 🚿 Regular watering
Oct 1.7" 0.6" 1.1" 🚿 Regular watering
Nov 1.7" 1.5" 0.2" 💧 Light watering
Dec 1.7" 2.4" 0" ✅ Rainfall sufficient

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

Chives 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.

Chives needs ~1,988 GDD — county provides 7,526 GDD Excellent fit

Chives Planting Timeline — Riverside County, CA

Chives Planting Calendar

Activity When Date Range
Transplant Outdoors March 3 Mar 3 – Mar 17
Harvest May 5 May 5 – Jul 14

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Transplant Outdoors
April
May Harvest
June Harvest
July Harvest
August
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.4"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 10a

📆 Growing Season

283 days in Riverside County

Growing Tips for Chives in Riverside County

Direct sow Chives outdoors after February 24 in Riverside County when soil has warmed and frost danger has passed.

With summer highs reaching 102°F in Riverside County, provide afternoon shade for Chives and water deeply in the morning.

Common pests for Chives in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

Start from seed or divisions in spring. Cut back to 2 inches after flowering to encourage fresh growth. Both the leaves and flowers are edible and delicious.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Chives in Riverside County, CA?

Riverside County is in Zone 10a with an average last frost of February 24. Plan your Chives planting based on this frost date — see the calendar above for exact timing.

What planting zone is Riverside County, CA?

Riverside County, California is in USDA Hardiness Zone 10a. The average last spring frost is February 24 and first fall frost is December 4.

🌱

Your Riverside County Garden Planner — Free

A 24-page printable planner built for Riverside County (Zone 10a). 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 Riverside County, CA. 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.