When to Plant Scallions in Palo Alto County, IA
Scallions (green onions) are mild-flavored alliums harvested for their slender green tops and white bases. They are quick-growing and perfect for succession planting.
Palo Alto County, Iowa is in USDA Zone 4b. The average last spring frost is April 27 and the first fall frost is October 8, giving you a growing season of approximately 164 days.
At an elevation of 1,358 feet, Palo Alto County receives approximately 34.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Scallions to ensure they mature before fall.
Palo Alto County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-6.9
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.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Scallions Planting Timeline — Palo Alto County, IA
Scallions Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 16 | Mar 16 – Mar 30 |
| Transplant Outdoors | April 27 | Apr 27 – May 11 |
| Direct Sow | April 20 | Apr 20 – May 11 |
| Fall Sowing | July 16 | Jul 16 – Jul 30 |
| Harvest | June 22 | Jun 22 – Jul 20 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Fall Sowing Harvest |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
50–70 days
Soil pH
6 – 7
USDA Zone
Zone 4b
Growing Season
164 days
Growing Tips for Palo Alto County
Direct sow every 3 weeks for continuous harvest. Thin to 1 inch apart or grow in clusters. Harvest when pencil-thick by pulling or cutting at soil level.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Scallions in Other Locations
Frequently Asked Questions
When should I plant Scallions in Palo Alto County, IA?
Palo Alto County is in Zone 4b with an average last frost of April 27. Plan your Scallions planting based on this frost date — see the calendar above for exact timing.
What planting zone is Palo Alto County, IA?
Palo Alto County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is April 27 and first fall frost is October 8.
Plan Your Garden with Confidence
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