Growing perennial strawberries successfully in Iowa requires specific attention to planting time and winter preparation due to the state’s fluctuating temperatures and harsh cold season. The primary goal is establishing a robust root system in the first year so the plants can survive the winter and produce a substantial harvest the following spring. Ignoring the regional climate can lead to plant death or a diminished yield, making proper timing and care essential. This process ensures the strawberry bed remains productive for many years.
The Ideal Time to Plant Strawberry Crowns
The most successful time for planting bare-root strawberry crowns in Iowa is early spring. This timing maximizes the plant’s initial growth period. Gardeners should plant as soon as the soil is dry enough to be worked without compacting, typically from mid-April to early May across the state. Planting during this cool period allows the roots to establish themselves firmly before the stress of summer heat arrives.
The concept of “workable soil” is more reliable than fixed calendar dates, as Iowa’s spring weather varies significantly year to year. Spring planting ensures the young crowns have the entire growing season to develop a strong root system and produce the runners that will form the productive bed for the next year. Although late summer or fall planting is possible, the spring method is preferred for establishing new perennial beds. Fall-planted crowns face a higher risk of winter damage before they can adequately establish themselves.
Choosing the Right Strawberry Type and Planting System
For long-term success in the Iowa climate, growers rely on June-bearing strawberry varieties. These plants develop flower buds in the late summer and fall as days shorten and temperatures cool, leading to a single, concentrated harvest the following June. June-bearers are the most cold-hardy and best suited for the state’s intense winter conditions. Other types, such as Everbearing and Day-neutral varieties, produce fruit throughout the summer but are often less vigorous and require more intensive management for winter survival.
The preferred planting method for June-bearing varieties is the Matted Row system. This system involves setting the initial crowns 18 to 24 inches apart in rows spaced four feet apart. The mother plants send out runners, which root freely to form a dense, matted row about two feet wide. This dense establishment is beneficial because the numerous resulting plants provide a naturally insulating cover, which aids in better winter survival compared to single plants. The alternative, the Hill System, requires continual removal of all runners, a labor-intensive practice better suited to day-neutral varieties.
Critical Steps for First-Year Establishment and Winter Survival
Successful long-term cultivation requires specific actions immediately after planting and throughout the first year to ensure plant survival and future productivity. Initially, the planting site should be in full sun and must have well-drained soil, as wet conditions can lead to root and leaf diseases. It is also important to avoid planting strawberries in areas that recently grew tomatoes, potatoes, or peppers, as these can harbor diseases that affect the crowns.
The most important step for first-year June-bearing plants is removing all blossoms as they appear. This practice redirects the plant’s energy away from fruit production and into developing a robust root system and producing healthy runners. Without this flower removal, the plant will waste valuable energy on a small, first-year crop, hindering its ability to establish a strong perennial base for the following year. Consistent watering and weed control are also necessary throughout the summer to support the developing matted row.
Preparing the bed for winter is essential in Iowa to protect the crowns from freezing and thawing cycles that can heave plants out of the soil. A layer of clean, weed-free straw should be applied once the plants have acclimated to the cold and the ground has frozen, which is generally from early November in northern Iowa to late November in the southern regions. The straw should be applied to a depth of three to five inches, which will settle into a two- to four-inch protective blanket. This mulch insulates the crowns and flower buds, which are susceptible to damage when temperatures drop below 20 degrees Fahrenheit.
The mulch should remain in place throughout the winter and only be removed in the spring when approximately 25 percent of the plants are showing signs of new growth. It is important to leave the straw near the bed, often raked into the aisles, so it can be quickly pulled back over the plants if a late spring frost threatens the emerging flowers. This final step ensures the plant’s hard-earned winter survival is not undone by a sudden drop in temperature just before harvest.