Choosing and Growing Greenhouse Plants in Iowa

How to Choose and Grow Your Own Plants & Crops in the State of Iowa, United States


The State of Iowa is a Midwestern state with a humid continental climate, meaning that it experiences extremes in heat and cold. Gardeners in Iowa often use small, large, commercial, and luxury greenhouses to care for warm-weather plants during the winter, a process known as overwintering. This requires careful timing that depends on the weather and the specific plants.


 Iowas State Flower Wild Rose Greenhouse Gardens


General Information about Iowa Agriculture:


Iowa Greenhouse Gardening Tutorial IA United States of America FlagThe northern part of Iowa is prairie with native vegetation such as dense grasses and a sparse population of trees. Southern Iowa is primarily flood plains and river valleys that contain dense forests and wetlands. Commercial agriculture accounts for 60 percent of the land use in Iowa.


The USDA Plant Hardiness Zone Map shows that the climate in Iowa ranges from Plant Hardiness Zone 4b to 5b.

  1. This means that the average annual low temperature in Iowa ranges from -25 Fahrenheit to -10 Fahrenheit.
  2. Snow is a routine event in Iowa and the winters can be harsh.
  3. Severe thunderstorms often occur during the spring, and an average of 50 days of thunderstorm activity occurs each year in Iowa.
  4. Summers in Iowa are hot and humid, with daytime temperatures often near 90 degrees Fahrenheit.

Greenhouse Gardening in Iowa U.S. of A.


Greenhouses offer distinct advantages for gardeners in Iowa.

  • Plants in an outside garden are often killed by an unexpected freeze and dramatic fluctuations in soil temperature can be harmful to outside plants, especially if they are in containers.
  • The cold dry air in Iowa can also cause tissue burn due to rapid evaporation. Rats are a common pest in Iowa, and they often feed on garden plants.

Growing Cherries in a Greenhouse


Gardeners in Iowa often cease their activities completely if they don’t have a greenhouse.

Overwintering in a greenhouse allows many plants to live as perennials, meaning that an individual plant lives longer than one year. The plants that are most commonly overwintered in Iowa include flowers and ornamental plants.


Greenhouse vegetables that are commonly grown as perennials include the following:

  1. Asparagus
  2. Garlic
  3. Many peppers
  4. Shallots
  5. Sweet beets
  6. Sweet potatoes


The Des Moines as it was depicted in 1718 by G...

The Des Moines as it was depicted in 1718 by Guillaume Delisle; modern Iowa highlighted. (Photo credit: Wikipedia)


Berries such as blackberries, blueberries and raspberries grow well in the greenhouse during the winter.

  • Most herbs such as parsley, chives and basil also adapt well to overwintering.
  • Plants that are overwintered in a greenhouse typically continue to bloom, although they do not do so as profusely as they did during the summer.
  • Overwintering provides these plants with a head start on the next year’s growing season, allowing them to have better production during their second summer.

3 Deminsional Wooden Greenhouse Kit Design Concept & Plan


Gardeners who wish to overwinter their plants need to bring them into the greenhouse before the plants enter their dormant period for the winter.

  • This occurs when the days become shorter and typically occurs by late August in Iowa.
  • Begin the overwintering process by reducing the fertilization and watering of these plants.
  • Dormant plants should only receive enough water to prevent the soil from becoming completely dry.
  • It is also important to wait as long as possible to bring plants into the greenhouse.
  • The plants may experience a delay in their hardening-off process if you bring them in too early, which can make them vulnerable to cold temperatures.


Successful overwintering requires a high degree of control over the temperature within the greenhouse.

  1. Plants that are native to Iowa typically require a period of cool weather to prevent poor out-of-season growth.
  2. On the other hand, plants that are frost tender can be killed by freezing temperatures.
  3. The ideal temperature in a greenhouse is therefore around 50 degrees Fahrenheit when it’s used for overwintering.
  4. Prune the plants by mid-March to remove undesired growth and prepare the plants for the new growing season.
  5. Increase the temperature in the greenhouse to 65 degrees Fahrenheit during the day and 55 degrees Fahrenheit at night.
  6. Apply a round of half-strength fertilizer to the plants before transplanting them.

Greenhouse (Photo credit: IITA Image Library)


Greenhouse Gardeners Picture Image Gallery Logo

The best time to move overwintered green house plants into the garden is a critical decision for Iowa gardeners.

  1. The Iowa State University Extension provides specific information on the factors involved in this process.
  2. Cool-weather plants such as calendars, pansies and snapdragons can tolerate frost and will even thrive in cool weather.
  3. Transplant these flowers into the garden as soon as you can work the soil, which usually occurs between mid-March and mid-May.


The last frost in northern Iowa typically occurs by May 15, which is the earliest date that you should plant warm-weather plants.

  • These plants can’t tolerate any frost and generally require warm air and soil to begin growing.
  • Warm-weather plants often require temperatures above 80 degrees Fahrenheit to achieve their best growth.

Greenhouse Kits and Garden Supplies

Gardeners in Iowa often grow the following warm-weather plants in their greenhouses:

  1. African daisy
  2. Begonia
  3. Impatiens
  4. Lantana
  5. Madagascar periwinkles
  6. Marigolds
  7. Morning glory
  8. Pentas
  9. Peppers
  10. Petunias

Greenhouse (Photo credit: IITA Image Library)



Harden off warm-weather gradually so they can adjust to variations in rain, sun and wind.

  • This typically involves placing them outside during the day so they are protected from the wind.
  • Bring the plants back into the greenhouse before dark, and repeat this pattern for a few days.
  • Leave the plant outside at night in a protected position for at least one week before planting them in the open.
  • Place the plants at the same depth in the ground as they were in the container.

General Information about Iowa Agriculture:

Local Links on Agriculture in Iowa U.S.A

Iowa Department of Agriculture and Land Stewardship



The Iowa Departments of Agriculture of Land Stewardship is well known for being an excellent agricultural business 2 business and general informational resource. The government organization is split up into 15 separate bureaus, that together form a powerful farming and horticulture tool.

Iowa Department of Agriculture and Land Stewardship Logo

Dept. of Agriculture & Landscape Stewardship Bureaus


24/7 Expert Greenhouse Gardening Customer Service Woman on Phone

24/7 Expert Greenhouse Gardening Customer Service Woman on Phone

Departments and Important Resources

Directory of all Iowa government licensing, permit acquiring, and regulations forms, to choose from.


2006 Iowa State USA Industries Gross Products by Industy


Iowa State University (ISU): College of Agriculture and Life Sciences


Iowa State University College of Agriculture and Life Sciences LogoISU Departments:

Iowa State Patrol

Iowa State Patrol (Photo credit: Wikipedia)


Agriculture and Natural Resources Website


Iowa’s AG and Natural Resource’s official webpage provides an extensive guide of directory resources, which refers to all things related to gardening, horticulture, and agriculture within the state.


State Organizations:



State Map of Iowa United States of America


USDA Logo: United States Department of Agriculture

United Stated Department of AgricultureUSDA RSS News Feed

Title: StrikeForce for Rural Growth and Opportunities

Publication Company: United States Department of Agriculture (USDA)

Credits: USDA YouTube Channel

Video Description: In 2010, USDA launched the StrikeForce ( for Rural Growth and Opportunity — an effort to leverage partnerships in poverty-stricken rural areas to ensure that every community has equal access to USDA programs. This short film looks at success stories from the initiative in Arkansas and Georgia reported in the Spring of 2013. From healthier, more profitable farms to tele-medicine to safe drinking water, StrikeForce is making a difference in America’s neediest places.

Run-time: 9 minutes, 32 seconds.

Total Views (Since 04/04/2013): 2,026

Rating: 5/5


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