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When to Plant Calabash in Benton County, OR

Benton County, Oregon Zone 8b May

May to-do list for Benton County, Oregon

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

Avg. last frost April 14
Avg. first frost October 30
Soil temp (4") 72°F
Watering Moderate
Pest pressure High
Daylight 14.6 hrs
Coming up in June — start thinking about
  • Starting indoors: 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.

Benton County, Oregon is in USDA Zone 8b. The average last spring frost is April 14 and the first fall frost is October 30, giving you a growing season of approximately 199 days.

At an elevation of 97 feet, Benton County receives approximately 53.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Calabash during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Calabash root diseases.

Benton County, OR (Zone 8b) Moderate season
199 days
Last Spring Frost April 14
199 growing days
First Fall Frost October 30

Benton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (57 days to spare)
Start indoors: Feb 6 Transplant: Apr 10 🍅 Harvest: Jul 3 – Aug 28
Recommended (50%) ✓ Fits season (45 days to spare)
Start indoors: Feb 24 Transplant: Apr 28 🍅 Harvest: Jul 21 – Sep 15
Safe Start (90%) ✓ Fits season (52 days to spare)
Start indoors: Mar 19 Transplant: May 21 🍅 Harvest: Aug 13 – Oct 8

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 Benton County

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

Soil pH

Your soil pH (5.6–6.2) is more acidic than Calabash prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — Calabash will thrive.

How to Plant Calabash

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

Succession Planting Calabash

2
successive plantings in your 199-day season

Sow every 9.1 weeks. Last sowing by Jul 02 to harvest before frost.

Plant Water Budget

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

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 8.1" 0" ❄️ Dormant
Feb 6.1" 0" ❄️ Dormant
Mar 5.8" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 1.9" 2.4" 🚿 Regular watering
Jul 4.3" 0.9" 3.4" 🚿 Regular watering
Aug 4.3" 0.8" 3.5" 🚿 Regular watering
Sep 4.3" 2.3" 2" 💧 Light watering
Oct 4.3" 3.8" 0.5" 💧 Light watering
Nov 8.3" 0" ❄️ Dormant
Dec 8.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Benton 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 ~1,375 GDD — county provides 2,736 GDD Excellent fit

Calabash Planting Timeline — Benton County, OR

Calabash Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 – Mar 10
Transplant Outdoors April 28 Apr 28 – May 12
Direct Sow April 21 Apr 21 – May 12
Harvest July 21 Jul 21 – Sep 15

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

199 days in Benton County

Growing Tips for Calabash in Benton County

Direct sow Calabash outdoors after April 14 in Benton County when soil has warmed and frost danger has passed.

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.

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 Benton County, OR?

Benton County is in Zone 8b with an average last frost of April 14. Plan your Calabash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Benton County, OR?

Benton County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 14 and first fall frost is October 30.

🌱

Your Benton County Garden Planner — Free

A 24-page printable planner built for Benton County (Zone 8b). 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 Benton County, OR. 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.