When to plant Sweet Pea in Boone County County,
The best window to plant Sweet Pea in Boone County County, is March 24–April 14, when soil warms to 50°F. Last frost typically hits April 28; first frost October 6.
When to Plant Sweet Pea in Boone County, IA
What to do in June
Your Boone County, Iowa garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.
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Fire up the seed-starting tray: sweet pea
Label every cell. You will absolutely forget which is which otherwise.
Coming up in July — start thinking about
- First harvests: sweet pea
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.
Boone County, Iowa is in USDA Zone 5a. The average last spring frost is April 28 and the first fall frost is October 6, giving you a growing season of approximately 161 days.
At an elevation of 950 feet, Boone County receives approximately 30.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Sweet Pea during the growing season.
Boone County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-6.9
Drainage
Well Drained
Sweet Pea 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 Boone County
How your county's soil matches Sweet Pea's growing requirements.
Soil pH
Your soil pH (6.1–6.9) is more acidic than Sweet Pea prefers (7.0–7.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Boone County is excellent for Sweet Pea — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.2%) — Sweet Pea will thrive.
How to Plant Sweet Pea
Succession Planting Sweet Pea
Sow every 7.4 weeks. Last sowing by Jul 13 to harvest before frost.
Sweet Pea Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
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 | — | 1.2" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| May | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Jun | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Jul | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Aug | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Sep | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Oct | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Nov | — | 2.2" | 0" | ❄️ Dormant |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Boone 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 Planting Timeline — Boone County, IA
Sweet Pea Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 17 | Mar 17 – Mar 31 |
| Transplant Outdoors | April 28 | Apr 28 – May 12 |
| Direct Sow | March 24 | Mar 24 – Apr 14 |
| Bloom | July 14 | Jul 14 – Sep 15 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
65–85 days
🧪 Soil pH
Needs 7–7.5 · Your soil: too_acidic
🗺️ USDA Zone
Zone 5a
📆 Growing Season
161 days in Boone County
Growing Tips for Sweet Pea in Boone County
Direct sow Sweet Pea outdoors after April 28 in Boone 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 →
Sweet Pea in Other Locations
Frequently Asked Questions
When should I plant Sweet Pea in Boone County, IA?
Boone County is in Zone 5a with an average last frost of April 28. Plan your Sweet Pea planting based on this frost date — see the calendar above for exact timing.
What planting zone is Boone County, IA?
Boone County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 28 and first fall frost is October 6.
When should I plant Sweet Pea in Boone County County, ?
In Boone County County, , plant Sweet Pea after the last frost (around April 28) and before the first frost (around October 6). Best results when soil holds above 50°F.
What growing zone is Boone County County, for Sweet Pea?
Boone County County sits in USDA Zone 5a. Sweet Pea grows reliably in zones 2a through 9b, so it's a good fit here.
Can Sweet Pea grow in Boone County County's climate?
Yes — Sweet Pea grows well in Boone County County's temperate climate. Boone County County averages a 161-day frost-free season, with last frost around April 28 and first frost around October 6.
Your Boone County Garden Planner — Free
A 22-page printable planner built for Boone County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.