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When to Plant Sweet Pea in Mapleton, OR

Mapleton, OR Zone 8b June

Your June gardening checklist

June is a pivotal month for Mapleton, OR gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 21
Avg. first frost October 25
Soil temp (4") 79°F
Watering High
Pest pressure High
Daylight 15.3 hrs

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Sweet peas (Lathyrus odoratus) are beloved cool-season climbing annuals grown primarily for their intensely fragrant, ruffled blooms in shades of pink, purple, red, and white. They thrive in cool spring conditions, climbing trellises to 4–6 feet, and make outstanding cut flowers. Bloom ceases once summer heat arrives, making early sowing critical for a long cutting season.

Mapleton, Oregon is in USDA Zone 8b. The average last spring frost is April 21 and the first fall frost is October 25, giving you a growing season of approximately 187 days.

At an elevation of 48 feet, Lane County receives approximately 50.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Sweet Pea to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sweet Pea root diseases.

Annual Blooms in Spring Pollinator-friendly Good for cutting Fragrant
Mapleton, OR (Zone 8b) Moderate season
187 days
Last Spring Frost April 21
187 growing days
First Fall Frost October 25
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Mapleton Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.4

Drainage

Well Drained

Sweet Pea Planting Risk Windows

Early Start (70% safe) ✓ Fits season (43 days to spare)
Transplant: Apr 13 🌸 Bloom: Jun 22 – Aug 31
Recommended (50%) ✓ Fits season (47 days to spare)
Transplant: Apr 21 🌸 Bloom: Jun 30 – Sep 8
Safe Start (90%) ✓ Fits season (52 days to spare)
Transplant: May 11 🌸 Bloom: Jul 20 – Sep 28

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 Mapleton

How your county's soil matches Sweet Pea's growing requirements.

Soil pH

Your soil pH (5.7–6.4) is more acidic than Sweet Pea prefers (7.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — Sweet Pea will thrive.

How to Plant Sweet Pea

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 9 weeks before your first frost date for a fall harvest.

Succession Planting Sweet Pea

3
successive plantings in your 187-day season

Sow every 7.4 weeks. Last sowing by Aug 01 to harvest before frost.

For a dedicated fall crop, sow by Aug 23.

Sweet Pea 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 Sweet Pea

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

Month Sweet Pea Needs Rainfall You Supplement Action
Jan 7.6" 0" ❄️ Dormant
Feb 5.3" 0" ❄️ Dormant
Mar 5.3" 0" ❄️ Dormant
Apr 4.3" 4" 0.3" 💧 Light watering
May 4.3" 2.5" 1.8" 💧 Light watering
Jun 4.3" 1.6" 2.7" 🚿 Regular watering
Jul 4.3" 0.8" 3.5" 🚿 Regular watering
Aug 4.3" 0.9" 3.4" 🚿 Regular watering
Sep 4.3" 2" 2.3" 🚿 Regular watering
Oct 4.3" 4.3" 0" ✅ Rainfall sufficient
Nov 8.3" 0" ❄️ Dormant
Dec 8" 0" ❄️ Dormant

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

Sweet Pea 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.

Sweet Pea needs ~806 GDD — county provides 2,010 GDD Excellent fit

Sweet Pea Planting Timeline — Mapleton, OR

Sweet Pea Planting Calendar

Activity When Date Range
Bloom November 1 Nov 1 – Jan 10
Fall Sowing August 23 Aug 23 – Sep 6

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January Bloom
February
March
April
May
June
July
August Fall Sowing
September Fall Sowing
October
November Bloom
December Bloom
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

65–85 days

🧪 Soil pH

Needs 7–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

187 days in Lane County

Growing Tips for Sweet Pea in Mapleton

Direct sow Sweet Pea outdoors after April 21 in Lane County when soil has warmed and frost danger has passed.

Common pests for Sweet Pea in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Soak seeds 24 hours before sowing to soften the hard seed coat; nick the seed coat with a file for the fastest germination. In cold zones (2–6), direct-sow as soon as soil can be worked, 4–6 weeks before last frost; seedlings tolerate light frost but not a hard freeze. In zones 7–9, fall-sow 8–10 weeks before first frost for earlier, stronger spring bloom. Provide a trellis or netting from the start. Feed with low-nitrogen, high-potassium fertilizer once buds form. Pick blooms regularly — even one mature seed pod stops flower production. All plant parts are mildly toxic if eaten.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

🌱

Your Lane County Garden Planner — Free

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