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When to Plant Bitter Melon in Winnebago County, WI

Winnebago County, Wisconsin Zone 5b May

What to do in May

Your Winnebago County, Wisconsin garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 30
Avg. first frost October 12
Soil temp (4") 55°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
  1. Get bitter melon in the ground

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Direct-sow bitter melon

    Your soil is 55°F — warm enough for these to germinate without babying.

Looking ahead to June
  • Starting indoors: 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.

Winnebago County, Wisconsin is in USDA Zone 5b. The average last spring frost is April 30 and the first fall frost is October 12, giving you a growing season of approximately 165 days.

At an elevation of 608 feet, Winnebago County receives approximately 38.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Bitter Melon to ensure they mature before fall.

Winnebago County, WI (Zone 5b) Moderate season
165 days
Last Spring Frost April 30
165 growing days
First Fall Frost October 12

Winnebago County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (44 days to spare)
Start indoors: Feb 28 Transplant: May 9 🍅 Harvest: Jul 11 – Aug 22
Recommended (50%) ✓ Fits season (46 days to spare)
Start indoors: Mar 5 Transplant: May 14 🍅 Harvest: Jul 16 – Aug 27
Safe Start (90%) ✓ Fits season (46 days to spare)
Start indoors: Mar 20 Transplant: May 29 🍅 Harvest: Jul 31 – Sep 11

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 Winnebago County

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

Soil pH

Your soil pH (6.3–6.7) is within Bitter Melon's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

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

How to Plant Bitter Melon

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

Succession Planting Bitter Melon

3
successive plantings in your 165-day season

Sow every 6.9 weeks. Last sowing by Jul 14 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 26 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 1.8" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4.4" 0" ✅ Rainfall sufficient
Aug 4.3" 4.5" 0" ✅ Rainfall sufficient
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Winnebago 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 ~862 GDD — county provides 1,897 GDD Excellent fit

Bitter Melon Planting Timeline — Winnebago County, WI

Bitter Melon Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 – Mar 19
Transplant Outdoors May 14 May 14 – May 28
Direct Sow May 7 May 7 – May 28
Harvest July 16 Jul 16 – Aug 27

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

Month-by-Month Timeline

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

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: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

165 days in Winnebago County

Growing Tips for Bitter Melon in Winnebago County

Direct sow Bitter Melon outdoors after April 30 in Winnebago County when soil has warmed and frost danger has passed.

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 Winnebago County, WI?

Winnebago County is in Zone 5b with an average last frost of April 30. Plan your Bitter Melon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Winnebago County, WI?

Winnebago County, Wisconsin is in USDA Hardiness Zone 5b. The average last spring frost is April 30 and first fall frost is October 12.

🌱

Your Winnebago County Garden Planner — Free

A 24-page printable planner built for Winnebago County (Zone 5b). 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 Winnebago County, WI. 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.