Clover is popular for its role as a ground cover, a nitrogen-fixing cover crop, or a lawn alternative. In Minnesota, characterized by a short growing season and cold winters, planting timing is the most important factor for success. Seeding clover at the wrong time can lead to failure from frost heave, summer drought, or premature germination. Success hinges on utilizing the state’s distinct seasonal transitions, including the spring warm-up and late fall dormancy, to achieve robust establishment.
Optimal Spring Planting Schedule
The primary window for establishing clover begins once the danger of a hard, killing frost has largely passed. Clover seeds can germinate in soil temperatures as low as 45°F, but optimal germination occurs when the soil temperature consistently reaches between 55°F and 65°F. This typically translates to a planting period from late April through May in the southern half of the state. Northern Minnesota, with its cooler climate, may need to wait until mid-May or even early June.
Planting during this spring window utilizes high soil moisture from snowmelt and spring rains. Clover needs sufficient time to develop a strong root system before the onset of summer heat and potential drought conditions. Sowing too late, particularly past mid-June, exposes vulnerable seedlings to heat stress and competition from aggressive summer weeds. Successful spring planting maximizes the first year’s growth, ensuring the plants are mature enough to survive the following winter.
Fall Planting and Dormant Seeding
Minnesota’s climate offers two distinct, effective planting opportunities outside of the spring window: traditional fall planting and dormant seeding. Traditional fall planting focuses on establishing the clover before the first hard frost, typically occurring in late August through early September. The goal is to provide four to six weeks for the seedlings to emerge and grow a strong first true leaf before the ground freezes.
This late summer timing is advantageous because weed pressure naturally declines, and soil moisture levels often increase. Sowing too late in the fall, however, can result in seedlings that are not mature enough to survive the winter and are vulnerable to frost heave.
The second method, dormant seeding, is a technique unique to cold climates where seeds are intentionally sown too late to germinate. This is done from late October or early November, once daytime air temperatures are consistently below 40°F, until the ground becomes permanently frozen or covered by deep snow. The objective is to keep the seeds inactive over winter, using the natural freeze-thaw cycles to work them into the soil for excellent seed-to-soil contact. When temperatures rise in early spring, the seeds are perfectly positioned to germinate much earlier than a traditional spring planting, giving the clover a significant head start before summer heat arrives.
Selecting the Right Clover Varieties for Minnesota
Choosing the appropriate clover species is important in a challenging environment like Minnesota. White Dutch Clover (Trifolium repens) is the most commonly recommended variety for lawns and general ground cover applications. It is a low-growing perennial that spreads by stolons, making it exceptionally resilient to mowing and foot traffic. White clover is highly tolerant of cold winters, and its nitrogen-fixing capabilities enrich the soil for surrounding turf.
For applications requiring greater biomass, such as cover cropping or forage production, Red Clover (Trifolium pratense) is often preferred. Red clover is taller and more upright than White Dutch Clover, offering deeper roots that contribute to greater nitrogen fixation and soil structure improvement.
In conditions where soil drainage is poor or the pH is slightly more acidic, Alsike Clover (Trifolium hybridum) is a superior choice. This variety is known for its tolerance of wet soils and is a reliable option for areas where Red Clover or White Clover might struggle with excess moisture.
The specific variety chosen influences planting success and longevity. White Dutch Clover is a true perennial that can last for many years. Red Clover is a short-lived perennial, often lasting only two to three years in the upper Midwest. Therefore, a successful long-term planting strategy may involve a blend of varieties to ensure a persistent stand over time.
Post-Planting Care and Establishment
After successful sowing, consistent moisture management is paramount for clover establishment. The tiny seeds must be kept constantly moist, not just wet, during the initial two-week germination period. Light, frequent watering is far more effective than heavy, infrequent soaking, which can wash seeds away or cause them to rot. Once the seedlings emerge, the watering frequency can be gradually reduced, encouraging the young plants to develop deeper, more resilient root systems.
Weed control is a major consideration during the establishment phase, as clover seedlings are highly susceptible to competition. Because clover is a broadleaf plant, most common lawn herbicides designed to kill broadleaf weeds will also kill the young clover. Hand-pulling or light, strategic mowing is the best way to manage weeds during the first season of growth.
The first mowing should generally be delayed until the clover has reached a height of about four inches and is well-established. Mowing should be done at a higher setting, ideally no lower than three inches, to avoid stressing the young plants. This initial cut helps control competing weeds and encourages the clover to spread laterally, leading to a denser, more robust stand.