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When to Plant Bitter Melon in Lake County, CA

Lake County, California Zone 9a May

Your May planting checklist for Lake County, California

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

Avg. last frost March 2
Avg. first frost November 27
Soil temp (4") 71°F
Watering Critical
Pest pressure High
Daylight 14.1 hrs
  1. Harvest bitter melon as they ripen

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

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

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Bitter melon is a tropical vine producing warty, bitter fruits used in Asian and Indian cuisine. The intense bitterness is prized for its culinary and health properties.

Lake County, California is in USDA Zone 9a. The average last spring frost is March 2 and the first fall frost is November 27, giving you a growing season of approximately 270 days.

At an elevation of 154 feet, Lake County receives approximately 30.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 83°F, so choose short-season varieties of Bitter Melon to ensure they mature before fall. Sandy soil warms quickly in spring — great for early planting — but Bitter Melon will need more frequent watering and organic matter to retain nutrients.

Lake County, CA (Zone 9a) Year-round
270 days
Last Spring Frost March 2
270 growing days
First Fall Frost November 27
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Lake County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.1-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (166 days to spare)
Start indoors: Jan 3 Transplant: Feb 21 🍅 Harvest: Apr 25 – Jun 6
Recommended (50%) ✓ Fits season (158 days to spare)
Start indoors: Jan 19 Transplant: Mar 9 🍅 Harvest: May 11 – Jun 22
Safe Start (90%) ✓ Fits season (129 days to spare)
Start indoors: Mar 6 Transplant: Apr 24 🍅 Harvest: Jun 26 – Aug 7

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 Lake County

How your county's soil matches Bitter Melon's growing requirements.

Soil pH

Your soil pH (6.1–6.9) is within Bitter Melon's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Bitter Melon.

How to Plant Bitter Melon

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Bitter Melon

5
successive plantings in your 270-day season

Sow every 6.9 weeks. Last sowing by Aug 29 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 1,267 gal / 100 sq ft

Monthly Watering Guide for Bitter Melon

Bitter Melon needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Bitter Melon Needs Rainfall You Supplement Action
Jan 6.2" 0" ❄️ Dormant
Feb 6.5" 0" ❄️ Dormant
Mar 4.3" 4.6" 0" ✅ Rainfall sufficient
Apr 4.3" 2.7" 1.6" 💧 Light watering
May 4.3" 0.8" 3.5" 🚿 Regular watering
Jun 4.3" 0.2" 4.1" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.3" 4" 🚿 Regular watering
Oct 4.3" 1.1" 3.2" 🚿 Regular watering
Nov 4.3" 3" 1.3" 💧 Light watering
Dec 5.1" 0" ❄️ Dormant

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

Bitter Melon 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.

Bitter Melon needs ~919 GDD — county provides 3,307 GDD Excellent fit

Bitter Melon Planting Timeline — Lake County, CA

Bitter Melon Planting Calendar

Activity When Date Range
Start Indoors January 19 Jan 19 – Feb 2
Transplant Outdoors March 9 Mar 9 – Mar 23
Direct Sow March 2 Mar 2 – Mar 23
Harvest May 11 May 11 – Jun 22

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 9a

📆 Growing Season

270 days in Lake County

Growing Tips for Bitter Melon in Lake County

Direct sow Bitter Melon outdoors after March 02 in Lake County when soil has warmed and frost danger has passed.

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

Common pests for Bitter Melon in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 4 weeks before last frost. Provide a trellis for climbing. Harvest fruits while still green and firm. Reduce bitterness by salting sliced fruit before cooking.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Bitter Melon in Lake County, CA?

Lake County is in Zone 9a with an average last frost of March 2. Plan your Bitter Melon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lake County, CA?

Lake County, California is in USDA Hardiness Zone 9a. The average last spring frost is March 2 and first fall frost is November 27.

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Your Lake County Garden Planner — Free

A 24-page printable planner built for Lake County (Zone 9a). 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 Lake 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.