When to Plant Lima Beans in San Juan County, WA
May in San Juan County, Washington — your action list
Welcome to May in Zone 9a. These are the moves that will have the biggest impact on your growing season.
A few tasks this May that'll pay off in June
- First harvests: lima beans
Lima beans are a warm-season legume producing large, creamy beans with a buttery texture. Both bush and pole varieties are available, with pole types yielding more.
San Juan County, Washington is in USDA Zone 9a. The average last spring frost is March 26 and the first fall frost is November 3, giving you a growing season of approximately 222 days.
At an elevation of 371 feet, San Juan County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Lima Beans to ensure they mature before fall.
San Juan County Soil Profile
Soil Type
Silt Loam
Soil pH
5.4-6.4
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 San Juan County
How your county's soil matches Lima Beans's growing requirements.
Soil pH
Your soil pH (5.4–6.4) is more acidic than Lima Beans prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in San Juan County is excellent for Lima Beans — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Lima Beans.
Organic Matter
Organic matter is excellent (4.8%) — Lima Beans will thrive.
How to Plant Lima Beans
Succession Planting Lima Beans
Sow every 6.9 weeks. Last sowing by Aug 05 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Lima Beans
Lima Beans needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.
| Month | Lima Beans Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 5.7" | 0" | ❄️ Dormant |
| Feb | — | 4.7" | 0" | ❄️ Dormant |
| Mar | 3.9" | 4.1" | 0" | ✅ Rainfall sufficient |
| Apr | 3.9" | 2.6" | 1.3" | 💧 Light watering |
| May | 3.9" | 2.6" | 1.3" | 💧 Light watering |
| Jun | 3.9" | 1.5" | 2.4" | 🚿 Regular watering |
| Jul | 3.9" | 0.6" | 3.3" | 🚿 Regular watering |
| Aug | 3.9" | 0.8" | 3.1" | 🚿 Regular watering |
| Sep | 3.9" | 1.8" | 2.1" | 🚿 Regular watering |
| Oct | 3.9" | 3.4" | 0.5" | 💧 Light watering |
| Nov | 3.9" | 6.4" | 0" | ✅ Rainfall sufficient |
| Dec | — | 6.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in San Juan County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Lima Beans 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.
Lima Beans Planting Timeline — San Juan County, WA
Lima Beans Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 2 | Apr 2 – Apr 23 |
| Harvest | June 4 | Jun 4 – Jul 16 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.9"/week · 1-2 times/week
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 9a
📆 Growing Season
222 days in San Juan County
Growing Tips for Lima Beans in San Juan County
Direct sow Lima Beans outdoors after March 26 in San Juan County when soil has warmed and frost danger has passed.
Common pests for Lima Beans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow after soil is thoroughly warm at 65F or above. Do not soak seeds before planting as they may crack. Harvest when pods are plump but still green for fresh limas.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Lima Beans in Other Locations
Frequently Asked Questions
When should I plant Lima Beans in San Juan County, WA?
San Juan County is in Zone 9a with an average last frost of March 26. Plan your Lima Beans planting based on this frost date — see the calendar above for exact timing.
What planting zone is San Juan County, WA?
San Juan County, Washington is in USDA Hardiness Zone 9a. The average last spring frost is March 26 and first fall frost is November 3.
Your San Juan County Garden Planner — Free
A 24-page printable planner built for San Juan 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.