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When to Plant Bitter Melon in Shasta County, CA

Shasta County, California Zone 9a May

This month in Shasta County, California

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

Avg. last frost June 6
Avg. first frost September 21
Soil temp (4") 70°F
Watering Critical
Pest pressure High
Daylight 14.3 hrs
June will be here before you know it — start on
  • Transplants going out: bitter melon
  • Direct-sowing: 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.

Shasta County, California is in USDA Zone 9a. The average last spring frost is June 6 and the first fall frost is September 21, giving you a growing season of approximately 107 days.

At an elevation of 81 feet, Shasta County receives approximately 40.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 85°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.

Shasta County, CA (Zone 9a) Short season
107 days
Last Spring Frost June 6
107 growing days
First Fall Frost September 21

Shasta County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (1 days to spare)
Start indoors: Apr 11 Transplant: May 30 🍅 Harvest: Aug 1 – Sep 12
Recommended (50%) ✗ May not fit
Start indoors: Apr 25 Transplant: Jun 13 🍅 Harvest: Aug 15 – Sep 26
Safe Start (90%) ✗ May not fit
Start indoors: May 11 Transplant: Jun 29 🍅 Harvest: Aug 31 – Oct 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 Shasta County

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

Soil pH

Your soil pH (5.7–6.8) overlaps with Bitter Melon's range (6.0–7.0), though not a perfect match.

Soil Texture

Sandy soil in Shasta 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 (2.6%). Annual compost additions will help Bitter Melon.

How to Plant Bitter Melon

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

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 7.7" 0" ❄️ Dormant
Feb 8" 0" ❄️ Dormant
Mar 6.8" 0" ❄️ Dormant
Apr 3.2" 0" ❄️ Dormant
May 1" 0" ❄️ Dormant
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" 0.4" 3.9" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 4.4" 0" ❄️ Dormant
Dec 7.1" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Shasta 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 ~1,031 GDD — county provides 1,471 GDD Excellent fit

Bitter Melon Planting Timeline — Shasta County, CA

Bitter Melon Planting Calendar

Activity When Date Range
Start Indoors April 25 Apr 25 – May 9
Transplant Outdoors June 13 Jun 13 – Jun 27
Direct Sow June 6 Jun 6 – Jun 27
Harvest August 15 Aug 15 – Sep 26

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

107 days in Shasta County

Growing Tips for Bitter Melon in Shasta County

Direct sow Bitter Melon outdoors after June 06 in Shasta County when soil has warmed and frost danger has passed.

Sandy soil in Shasta 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 Shasta County, CA?

Shasta County is in Zone 9a with an average last frost of June 6. Plan your Bitter Melon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Shasta County, CA?

Shasta County, California is in USDA Hardiness Zone 9a. The average last spring frost is June 6 and first fall frost is September 21.

🌱

Your Shasta County Garden Planner — Free

A 24-page printable planner built for Shasta 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 Shasta 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.