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When to plant Calabash in San Bernardino County County,

In San Bernardino County County, plant Calabash in spring between February 24 and March 17, once soil temps hold above 50°F. San Bernardino County County's last frost averages February 24, so aim for a steady week of warm soil before planting. For a fall crop, sow between and — roughly 120 days before the first frost on November 25.

When to Plant Calabash in San Bernardino County, CA

San Bernardino County, California Zone 10a June

Your June gardening checklist

A quick June briefing for San Bernardino County, California gardeners — what's urgent, what's next, and what can wait.

Avg. last frost February 24
Avg. first frost November 25
Soil temp (4") 86°F
Watering Critical
Pest pressure High
Daylight 14.3 hrs
  1. Harvest calabash as they ripen

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

July will be here before you know it — start on
  • First harvests: calabash

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Calabash (bottle gourd) is a tropical vine producing edible young fruits used in Asian and African cooking. Mature dried fruits serve as natural containers and utensils.

San Bernardino County, California is in USDA Zone 10a. The average last spring frost is February 24 and the first fall frost is November 25, giving you a growing season of approximately 274 days.

At an elevation of 1,012 feet, San Bernardino County receives approximately 16.9 inches of rainfall annually with predominantly loam soil. Summer highs average 97°F, so Calabash may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Calabash successfully. Mulch heavily to conserve soil moisture.

San Bernardino County, CA (Zone 10a) Year-round
274 days
Last Spring Frost February 24
274 growing days
First Fall Frost November 25
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San Bernardino County Soil Profile

Soil Type

Loam

Soil pH

5.9-7.2

Drainage

Well Drained

Calabash Planting Risk Windows

Early Start (70% safe) ✓ Fits season (133 days to spare)
Start indoors: Jan 2 Transplant: Feb 20 🍅 Harvest: May 15 – Jul 10
Recommended (50%) ✓ Fits season (127 days to spare)
Start indoors: Jan 13 Transplant: Mar 3 🍅 Harvest: May 26 – Jul 21
Safe Start (90%) ✓ Fits season (130 days to spare)
Start indoors: Jan 24 Transplant: Mar 14 🍅 Harvest: Jun 6 – Aug 1

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 San Bernardino County

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

Soil pH

Your soil pH (5.9–7.2) overlaps with Calabash's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in San Bernardino County is excellent for Calabash — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Calabash.

How to Plant Calabash

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

Succession Planting Calabash

4
successive plantings in your 274-day season

Sow every 9.1 weeks. Last sowing by Jul 28 to harvest before frost.

Calabash Water Budget

Plant needs
1.0″/week
Rainfall provides
0.3″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 2,179 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Calabash

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

Month Calabash Needs Rainfall You Supplement Action
Jan 3.2" 0" ❄️ Dormant
Feb 4.3" 3.8" 0.5" 💧 Light watering
Mar 4.3" 2.2" 2.1" 💧 Light watering
Apr 4.3" 1.5" 2.8" 🚿 Regular watering
May 4.3" 0.5" 3.8" 🚿 Regular watering
Jun 4.3" 0.1" 4.2" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.2" 4.1" 🚿 Regular watering
Oct 4.3" 0.7" 3.6" 🚿 Regular watering
Nov 4.3" 1.7" 2.6" 🚿 Regular watering
Dec 3" 0" ❄️ Dormant

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

Calabash 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.

Calabash needs ~2,275 GDD — county provides 6,256 GDD Excellent fit

Calabash Planting Timeline — San Bernardino County, CA

Calabash Planting Calendar

Activity When Date Range
Start Indoors January 13 Jan 13 – Jan 27
Transplant Outdoors March 3 Mar 3 – Mar 17
Direct Sow February 24 Feb 24 – Mar 17
Harvest May 26 May 26 – Jul 21

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 10a

📆 Growing Season

274 days in San Bernardino County

Growing Tips for Calabash in San Bernardino County

Direct sow Calabash outdoors after February 24 in San Bernardino County when soil has warmed and frost danger has passed.

With summer highs reaching 97°F in San Bernardino County, provide afternoon shade for Calabash and water deeply in the morning.

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

San Bernardino County receives only 17" of rain annually. Calabash needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 4 weeks early. Provide a very strong trellis for heavy fruits. Harvest young for cooking or let mature on the vine for crafts. Requires a long, warm season.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Calabash in San Bernardino County, CA?

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

What planting zone is San Bernardino County, CA?

San Bernardino County, California is in USDA Hardiness Zone 10a. The average last spring frost is February 24 and first fall frost is November 25.

When should I plant Calabash in San Bernardino County County, ?

In San Bernardino County County, , plant Calabash after the last frost (around February 24) and before the first frost (around November 25). Best results when soil holds above 50°F.

What growing zone is San Bernardino County County, for Calabash?

San Bernardino County County sits in USDA Zone 10a. Calabash grows reliably in zones 5a through 11b, so it's a good fit here.

Can Calabash grow in San Bernardino County County's climate?

Yes — Calabash grows well in San Bernardino County County's temperate climate. San Bernardino County County averages a 275-day frost-free season, with last frost around February 24 and first frost around November 25.

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Your San Bernardino County Garden Planner — Free

A 22-page printable planner built for San Bernardino 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 San Bernardino County, CA. Local conditions may vary. Last updated: June 2026.

Sources & credits

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