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When to Plant Lentils in Riverside County, CA

Riverside County, California Zone 10a May

This month in Riverside County, California

Welcome to May in Zone 10a. These are the moves that will have the biggest impact on your growing season.

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. Start harvesting lentils

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Coming up in June — start thinking about
  • First harvests: lentils

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Lentils are an ancient pulse crop producing small, lens-shaped seeds packed with protein and iron. They grow on short, bushy plants and are surprisingly easy to cultivate.

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 Lentils may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Lentils 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
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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 (170 days to spare)
Start indoors: Jan 6 Transplant: Feb 3 🍅 Harvest: Apr 28 – Jun 9
Recommended (50%) ✓ Fits season (157 days to spare)
Start indoors: Jan 27 Transplant: Feb 24 🍅 Harvest: May 19 – Jun 30
Safe Start (90%) ✓ Fits season (145 days to spare)
Start indoors: Feb 22 Transplant: Mar 22 🍅 Harvest: Jun 14 – Jul 26

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 Lentils's growing requirements.

Soil pH

Your soil pH (6.2–7.8) is within Lentils's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

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

How to Plant Lentils

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 Lentils

4
successive plantings in your 283-day season

Sow every 9.1 weeks. Last sowing by Aug 16 to harvest before frost.

For a dedicated fall crop, sow by Oct 09.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.2″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 1,125 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Lentils

Lentils needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Lentils Needs Rainfall You Supplement Action
Jan 3.5" 0" ❄️ Dormant
Feb 2.6" 3.6" 0" ✅ Rainfall sufficient
Mar 2.6" 2.2" 0.4" 💧 Light watering
Apr 2.6" 1.2" 1.4" 🚿 Regular watering
May 2.6" 0.4" 2.2" 🚿 Regular watering
Jun 2.6" 0.1" 2.5" 🚿 Regular watering
Jul 2.6" 0" 2.6" 🚿 Regular watering
Aug 2.6" 0" 2.6" 🚿 Regular watering
Sep 2.6" 0.2" 2.4" 🚿 Regular watering
Oct 2.6" 0.6" 2" 🚿 Regular watering
Nov 2.6" 1.5" 1.1" 💧 Light watering
Dec 2.6" 2.4" 0.2" 💧 Light watering

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.

Lentils 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.

Lentils needs ~2,518 GDD — county provides 7,526 GDD Excellent fit

Lentils Planting Timeline — Riverside County, CA

Lentils Planting Calendar

Activity When Date Range
Start Indoors January 27 Jan 27 – Feb 10
Transplant Outdoors February 24 Feb 24 – Mar 10
Direct Sow February 3 Feb 3 – Feb 24
Harvest May 19 May 19 – Jun 30
Fall Sowing October 9 Oct 9 – Oct 23

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
October Fall Sowing
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · 1-2 times/week

📅 Days to Maturity

80–110 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 10a

📆 Growing Season

283 days in Riverside County

Growing Tips for Lentils in Riverside County

Direct sow Lentils 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 Lentils and water deeply in the morning.

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

General growing tips

Direct sow in early spring as lentils tolerate frost. Provide short supports as plants tend to lodge. Harvest when lower pods turn brown. Pull entire plants and dry in bundles.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lentils in Riverside County, CA?

Riverside County is in Zone 10a with an average last frost of February 24. Plan your Lentils 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.