Blog

When to Plant Bitter Melon in Del Norte County, CA

Del Norte County, California Zone 9b May

Your May gardening checklist

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

Avg. last frost March 27
Avg. first frost November 20
Soil temp (4") 71°F
Watering Critical
Pest pressure High
Daylight 14.4 hrs
  1. Time to start bitter melon inside

    You're about 25 weeks out from your last frost — the perfect window to get these germinating indoors.

A few tasks this May that'll pay off in June
  • First harvests: bitter melon

Instant PDF download. No spam, unsubscribe any time.

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.

Del Norte County, California is in USDA Zone 9b. The average last spring frost is March 27 and the first fall frost is November 20, giving you a growing season of approximately 238 days.

At an elevation of 72 feet, Del Norte County receives approximately 43.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 89°F, providing good warmth for Bitter Melon during the growing season. Sandy soil warms quickly in spring — great for early planting — but Bitter Melon will need more frequent watering and organic matter to retain nutrients.

Del Norte County, CA (Zone 9b) Long season
238 days
Last Spring Frost March 27
238 growing days
First Fall Frost November 20
Share this guide:

Del Norte County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.9-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (125 days to spare)
Start indoors: Jan 22 Transplant: Mar 12 🍅 Harvest: May 14 – Jun 25
Recommended (50%) ✓ Fits season (126 days to spare)
Start indoors: Feb 13 Transplant: Apr 3 🍅 Harvest: Jun 5 – Jul 17
Safe Start (90%) ✓ Fits season (115 days to spare)
Start indoors: Mar 23 Transplant: May 11 🍅 Harvest: Jul 13 – Aug 24

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 Del Norte County

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

Soil pH

Your soil pH (5.9–7.0) overlaps with Bitter Melon's range (6.0–7.0), though not a perfect match.

Soil Texture

Sandy soil in Del Norte 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

4
successive plantings in your 238-day season

Sow every 6.9 weeks. Last sowing by Aug 22 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 481 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 8.3" 0" ❄️ Dormant
Feb 9.9" 0" ❄️ Dormant
Mar 4.3" 5.8" 0" ✅ Rainfall sufficient
Apr 4.3" 3.5" 0.8" 💧 Light watering
May 4.3" 1.1" 3.2" 🚿 Regular watering
Jun 4.3" 0.3" 4" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.4" 3.9" 🚿 Regular watering
Oct 4.3" 1.9" 2.4" 🚿 Regular watering
Nov 4.3" 4.7" 0" ✅ Rainfall sufficient
Dec 7.9" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Del Norte 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 ~1,256 GDD — county provides 3,986 GDD Excellent fit

Bitter Melon Planting Timeline — Del Norte County, CA

Bitter Melon Planting Calendar

Activity When Date Range
Start Indoors February 13 Feb 13 – Feb 27
Transplant Outdoors April 3 Apr 3 – Apr 17
Direct Sow March 27 Mar 27 – Apr 17
Harvest June 5 Jun 5 – Jul 17

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Direct Sow
April Transplant Outdoors Direct Sow
May
June Harvest
July Harvest
August
September
October
November
December
Share this guide:

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

238 days in Del Norte County

Growing Tips for Bitter Melon in Del Norte County

Direct sow Bitter Melon outdoors after March 27 in Del Norte County when soil has warmed and frost danger has passed.

Sandy soil in Del Norte 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 Del Norte County, CA?

Del Norte County is in Zone 9b with an average last frost of March 27. Plan your Bitter Melon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Del Norte County, CA?

Del Norte County, California is in USDA Hardiness Zone 9b. The average last spring frost is March 27 and first fall frost is November 20.

🌱

Your Del Norte County Garden Planner — Free

A 24-page printable planner built for Del Norte 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.

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 Del Norte 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.