When to Plant Scallions in Iowa (2026 Guide)
Scallions, also known as green onions or bunching onions, are a fantastic addition to your Iowa garden. Not only are they versatile in the kitchen, but they can also be grown quite successfully across various regions of the state. With the last spring frost date for Zone 6a being April 25, knowing when to plant is crucial for a bountiful harvest.
In Iowa, particularly in cities like Ames and Ankeny, scallions can be planted directly in the garden a few weeks after the frost, making them an ideal crop for many gardeners. For those in Zone 6b, with a last frost date of April 14, there’s an even earlier window to start growing these flavorful herbs. The growing season is relatively long, allowing for multiple plantings throughout the warmer months.
Scallions thrive in cool weather but can also withstand some heat, making them a flexible choice for Iowa gardeners. They can be harvested in approximately 60 to 70 days from planting. Whether you're tending a community plot in Des Moines or a backyard garden in Cedar Rapids, being mindful of these frost dates will optimize your yield.
Planting Schedule by USDA Zone in Iowa
| Zone | Indoor start | Transplant out | Direct sow | Harvest |
|---|---|---|---|---|
| Zone 6a | Start indoor planting February 24 – March 10, ~6–8 weeks before April 25 | Transplant outdoors April 26 – May 1, after the last frost date | Direct sow outdoors April 26 – May 1, after the last frost date | Harvest from June 25 – August 1, about 60–70 days after sowing |
| Zone 6b | Start indoor planting February 24 – March 10, ~6–8 weeks before April 14 | Transplant outdoors April 15 – April 20, after the last frost date | Direct sow outdoors April 15 – April 20, after the last frost date | Harvest from June 25 – August 1, about 60–70 days after sowing |
Scallions Planting Windows in Iowa
- Indoor start: For those in Iowa, the best indoor start window for scallions is from February 24 to March 10.
- Transplant outdoors: Transplant scallions outdoors in Iowa from April 15 to April 20 for Zone 6b, or April 26 to May 1 for Zone 6a.
- Harvest: The typical harvest window for scallions in Iowa is from June 25 to August 1.
Common Mistakes Growing Scallions in Iowa
- One common mistake among Iowa gardeners is planting too early while ignoring frost warnings. Especially in Zone 6a, waiting until after April 25 is crucial for successful germination. Late spring snow can ruin tender seedlings, so check forecasts before planting.
- Another frequent error is improper watering. Iowa's humidity can lead to overwatering, which may result in root rot. Scallions prefer well-draining soil, so ensure your garden bed has good drainage or consider raised beds.
- Failure to stagger plantings is a mistake many new gardeners make. Scallions can be sown every 3–4 weeks to maintain a continuous harvest. If you only plant once, you'll have a glut of scallions at once and none later in the season.
- Many gardeners also underestimate the potential of container gardening. Iowa can have limited space, especially in urban areas like Cedar Rapids. Scallions thrive in pots, which maximizes space and allows for mobility in your garden.
- Finally, some Iowa gardeners mistakenly believe scallions can be grown the same way as bulb onions. Unlike their bulbous counterparts, scallions do not require precise day-length timing, giving you more flexibility with planting times.
Frequently Asked Questions
What if I'm in a cold pocket of Iowa?
If you're in a cooler area, adjust your planting dates according to local frost dates. You may need to wait a few extra days after the last frost to ensure the soil is warm enough for scallion seeds to germinate.
Can I still plant scallions in May?
Yes, if you missed early planting, you can still direct sow or transplant scallions in May after the last frost. Just keep in mind that your harvest will likely be later than others who planted earlier.
How deep should I plant scallions?
Scallions should be planted about 1 inch deep in well-prepared soil. Ensure to keep the soil moist but not soggy to promote optimal growth.
Can I regrow scallion bases?
Yes, you can regrow scallion bases. After harvesting, leave 1-2 inches of the white base with roots and place it in moist soil or water. New green growth will appear quickly, allowing you to extend your harvest.
What do I do with scallions after a frost?
Frost can damage scallions, but they’re often still edible. If exposed to frost, use them in cooked dishes where texture matters less. Covering them with row cover can help protect your plants and extend the harvest season.
Keep Learning
City guides in Iowa
Other crops in Iowa
Typical fall sowing window for Scallions in Iowa: July 24 – August 14.