Iowa Planting Zones

The Hawkeye State, which spans approximately 310 miles from east to west, encompasses five planting zones: 4b, 5a, 5b, 6a, and 6b. 

This diverse range of hardiness zones allows various plants to thrive, from cold-hardy crops in the north to more temperate species in the south. 

Whether tending to a backyard garden in Des Moines or managing a sprawling farm in the Loess Hills, understanding Iowa's unique growing conditions is essential for agricultural success.
In this article, you will learn: 

 

Iowa's vast prairies and gently rolling hills, from the Missouri River valley in the west to the Mississippi River bluffs in the east, belie its rich agricultural heritage. 

As one of the nation's leading agricultural producers, Iowa offers many growing opportunities for home gardeners, too.
 

Image from USDA

Characteristics of Iowa’s Planting Region

Iowa's climate is humid continental, characterized by hot summers, cold winters, and ample precipitation throughout the year. 

The state's position in the heart of the Midwest, far from moderating coastal influences, leads to more extreme temperature fluctuations compared to coastal states.

As a gardener in the Hawkeye State, you can expect:

  • Hot summers, with July temperatures averaging around 74°F to 76°F (23.3°C to 24.4°C)
  • Cold winters, particularly in northern areas, with January averages ranging from 14°F to 22°F (-10°C to -5.6°C)
  • Significant temperature variations between seasons and even within a single day
  • Annual precipitation averaging 30-34 inches (76-86 cm), with slightly higher amounts in the southeast
  • Occasional extreme weather events, including tornadoes, severe thunderstorms, and blizzards

Despite these varied conditions, Iowa offers a favorable growing environment for many plants, especially those well-suited to continental climates. 

The state's growing season typically ranges from 150 days in the north to 180 days in the south, providing ample time for the cultivation of a wide variety of crops.

Challenges of Growing in Iowa

Temperature Fluctuations

Iowa's inland location leads to significant temperature swings, which can stress plants. Late spring frosts and early fall freezes can damage tender crops.

Soil Variability

While Iowa is famous for its rich, dark soil, soil types can vary across the state. The Loess Hills in western Iowa have wind-deposited silt soils, while parts of southern Iowa have clay-based soils that can be challenging for drainage.

Pest and Disease

The state's agricultural prominence can lead to significant pest and disease issues. Corn earworms, soybean aphids, and various fungal diseases are common challenges for Iowa gardeners and farmers.

The Benefits of Using a Greenhouse in Iowa

While Iowa's climate supports a robust agricultural sector, a greenhouse can significantly enhance your growing capabilities:

1. Extend Your Growing Season 

  • Without a Greenhouse: In central Iowa, outdoor planting typically begins in early May and ends in late September to early October.
  • With a Greenhouse: Greenhouse gardeners can start seeds as early as late February and continue harvesting into late November or even December. This extension is particularly beneficial for warm-season crops like tomatoes, peppers, and cucumbers.

Learn more about your area's specific growing dates and the best vegetables to plant in each part of Georgia.

Customer images of their Greenhouse setup in Iowa

2. Grow a Wider Variety of Vegetables Without a Greenhouse: 

  • Without a Greenhouse

Iowa's outdoor conditions are ideal for crops like:

  • Corn (sweet corn plantings from early May to early July)
  • Soybeans (typically planted in May)
  • Potatoes (planted in April)
  • Peaches
  • Cucumbers
  • Squash
  • Cantaloupes
  • Lima beans
  • With a Greenhouse

You can create microclimates suitable for a wider variety of plants, including:

  • Arugula,
  • Spinach, 
  • Broccoli,
  • Cauliflower, 
  • Brussels sprouts, 
  • Tomatoes, 
  • Peppers,
  • Melons
  • Eggplant, Cucumbers, environment)
  • Zucchini, 
  • Carrots, 
  • Beets, 
  • Radishes)
  • Kale, 
  • Swiss chard,
  • Collard greens)
  • Basil, 
  • Cilantro
  • Parsley,
  • Rosemary,
  • Thyme, 
  • Green beans, Green onions,
  • Leeks)
  • Lemons,
  • Limes,
  • Kumquats,
  • Figs

Why Planta Greenhouses?

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