When to Plant Butternut Squash in Yamhill County, OR
Yamhill County, Oregon gardeners: here's your May plan
Your Yamhill County, Oregon garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.
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Indoor seed-starting week for butternut squash
Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.
Butternut squash is a popular winter squash with a long neck, small seed cavity, and sweet, nutty orange flesh. It stores exceptionally well for months.
Yamhill County, Oregon is in USDA Zone 8b. The average last spring frost is April 15 and the first fall frost is October 27, giving you a growing season of approximately 195 days.
At an elevation of 476 feet, Yamhill County receives approximately 54.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Butternut Squash during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Butternut Squash root diseases.
Yamhill County Soil Profile
Soil Type
Silt Loam
Soil pH
5.4-6.2
Drainage
Well Drained
Plant Planting Risk Windows
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 Yamhill County
How your county's soil matches Butternut Squash's growing requirements.
Soil pH
Your soil pH (5.4–6.2) is more acidic than Butternut Squash prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Yamhill County is excellent for Butternut Squash — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Butternut Squash.
Organic Matter
Organic matter is excellent (4.3%) — Butternut Squash will thrive.
How to Plant Butternut Squash
Plant Water Budget
Monthly Watering Guide for Butternut Squash
Butternut Squash needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.
| Month | Butternut Squash Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 7.4" | 0" | ❄️ Dormant |
| Feb | — | 6.4" | 0" | ❄️ Dormant |
| Mar | — | 5.1" | 0" | ❄️ Dormant |
| Apr | 4.8" | 3.5" | 1.3" | 💧 Light watering |
| May | 4.8" | 2.8" | 2" | 💧 Light watering |
| Jun | 4.8" | 2.1" | 2.7" | 🚿 Regular watering |
| Jul | 4.8" | 0.9" | 3.9" | 🚿 Regular watering |
| Aug | 4.8" | 1" | 3.8" | 🚿 Regular watering |
| Sep | 4.8" | 2.4" | 2.4" | 🚿 Regular watering |
| Oct | 4.8" | 4.8" | 0" | ✅ Rainfall sufficient |
| Nov | — | 9.3" | 0" | ❄️ Dormant |
| Dec | — | 8.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Yamhill County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Butternut Squash 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.
Butternut Squash Planting Timeline — Yamhill County, OR
Butternut Squash Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 18 | Mar 18 – Apr 1 |
| Transplant Outdoors | April 29 | Apr 29 – May 13 |
| Direct Sow | April 22 | Apr 22 – May 13 |
| Harvest | July 29 | Jul 29 – Sep 2 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors 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
1.1"/week · Only during dry spells
📅 Days to Maturity
85–110 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 8b
📆 Growing Season
195 days in Yamhill County
Growing Tips for Butternut Squash in Yamhill County
Direct sow Butternut Squash outdoors after April 15 in Yamhill County when soil has warmed and frost danger has passed.
Common pests for Butternut Squash 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 3 weeks early or direct sow after frost. Allow 6-8 feet for sprawling vines. Harvest when the skin is hard and uniformly tan. Cure in the sun for 10 days.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Butternut Squash in Other Locations
Frequently Asked Questions
When should I plant Butternut Squash in Yamhill County, OR?
Yamhill County is in Zone 8b with an average last frost of April 15. Plan your Butternut Squash planting based on this frost date — see the calendar above for exact timing.
What planting zone is Yamhill County, OR?
Yamhill County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 15 and first fall frost is October 27.
Your Yamhill County Garden Planner — Free
A 24-page printable planner built for Yamhill 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.