When to Plant Peas in Iowa City, IA
Published: April 24, 2026
Pea Planting Dates for Iowa City, IA
| Start seeds indoors | Year-round |
| Last frost (average) | April 7 |
| Direct sow outdoors | March 3–13 |
| Minimum soil temperature | 40°F |
| Expect first harvest | April 27 – May 12 |
| Fall crop planting | August 13–23 |
| Fall crop harvest | October 7 |
| First fall frost (average) | October 22 |
⚠ Plant peas 4–6 weeks before last frost — one of the first vegetables of spring. Tolerate light frost. Also plant in late summer for a fall harvest.
Best Pea Varieties for Iowa City, IA
Consult a Iowa City-area nursery or your state extension office for pea varieties proven in Zone 5b.
Growing Peas in Iowa City
Iowa City sits in Zone 5b, with an average last frost of April 7 and first fall frost around October 22 — giving a 198-day frost-free growing season. Cool-season crops like pea benefit from Iowa City's cooler spring and fall windows, when temperatures stay in the 55–75°F sweet spot that produces the best flavor and least bolting.
Iowa City's cooler summers are close to ideal for pea. The same conditions that limit tomato and pepper yields benefit cool-season crops — slower bolting, sweeter flavor, and longer harvest windows. The fall pea crop in Iowa City is often more productive than the spring crop.
Iowa City's clay-loam soils are productive but benefit from annual compost amendment — 2 to 3 inches worked in before planting improves drainage and nutrient availability for pea. Consistent watering (1 inches per week) paired with organic mulch maintains the even moisture that clay-loam holds well. Avoid working wet soil in spring, which causes severe compaction in clay-loam blends.
Pea Calendar for Iowa City
| Month | Task |
|---|---|
| Year | Start seeds indoors under grow lights |
| April | Last frost — soil warming, prepare bed |
| March | Direct sow seeds into warm soil |
| April | Expect first harvest window to open |
| August | Start fall crop — transplants or direct sow |
| October | First fall frost — harvest remaining, end of outdoor season |
Pea Tips for Iowa City Gardeners
- •Soak pea seeds overnight before planting to speed germination in cool soil.
- •Install a 4–6 foot trellis at planting time — peas climb from day one and produce more per square foot when supported.
- •Fall plantings in Iowa City often out-produce spring plantings — cooler temperatures slow bolting and concentrate flavor. Light frost can actually improve the taste of pea.
Common Pea Pests in Iowa City
- •Pea Aphid — peaks July in Zone 5b (active June–August); monitor closely during peak season and treat early.
- •Powdery Mildew — peaks July in Zone 5b (active June–August); white powdery coating on leaves; improve airflow and apply milk spray (1:9 milk-to-water).
- •Root Rot — peaks July in Zone 5b (active June–August); monitor closely during peak season and treat early.
Check plants every 2–3 days during peak season — early intervention prevents most infestations from becoming serious.
What to Plant with Peas in Iowa City
In Iowa City's cold climate, Carrot and Radish are the most beneficial plants to grow alongside pea. Carrot shares root-zone space without competing because carrot roots run deeper than most companions. Keep pea away from Onion — it inhibits bean and pea growth through sulfur-compound allelopathy. In short-season gardens, interplanting companions at transplant time maximizes each bed's productive weeks.
Frequently Asked Questions
When should I plant pea in Iowa City, IA?
In Iowa City (Zone 5b), direct sow pea around March 3–13. Soil must be at 40°F or warmer at 2-inch depth before sowing — cold soil rots the seeds.
What zone is Iowa City, IA for pea growing?
Iowa City is USDA Zone 5b. For pea, this means a frost-free growing season of roughly 28 weeks running from April 7 to October 22. Cool-season crops like pea thrive in this zone with both spring and fall planting windows available.
When is pea harvest season in Iowa City?
Expect the first pea harvest in Iowa City around April 27, with harvest continuing through May 12. This is based on 55–70 days from transplant or direct sow. A fall crop planted August 13–23 adds a second harvest around October 7.
How long does it take to grow pea in Iowa City, IA?
From transplant or direct sow to first harvest, pea takes 55–70 days in Iowa City's climate. Based on a typical planting date of March 3–13, expect your first harvest around April 27. Iowa City's cooler Zone 5b climate often lands at the slower end of this range — cooler nights slow fruit development.
What soil does pea need in Iowa City?
Iowa City's clay-loam soil is productive for pea but benefits from annual compost amendment. Work 2–3 inches of compost into the top 10 inches before planting. Avoid working wet soil in spring — clay-loam compacts badly when wet. Consistent watering paired with organic mulch maintains the even moisture these soils hold well.