When to Seed Your Prairie
Early Spring | Late Spring | Fall Planting
Certain species have specific times of the season when they germinate best.
Most wildflowers will exhibit higher germination when seeded in the fall. Seed can be planted directly into the ground, or into flats or pots that are allowed to over-winter in a cool, damp location protected from drying winds.
Cool season grasses and flowers, such as Junegrass, Prairie Dropseed, and Asters do best when planted in early spring when temperatures are cooler. Sedges also do better when planted in fall or early spring. Many prairie species do well when planted in mid to late spring after temperatures have warmed up. This is particularly true of the warm season prairie grasses, such as Big Bluestem, Little Bluestem, Side Oats Grama, Indiangrass, and Switchgrass.
If your goal is to establish both flowers and grasses together, it is best to plant in fall or early spring, provided that the site has been properly prepared and is free of weed problems.
Seeding prairies in late spring or early summer typically produces excellent results. Most prairie wildflowers and grasses are warm season plants that germinate best after soil temperatures have warmed up. In contrast, cool season lawn grasses do better when planted in fall or early spring when soil temperatures are cooler. Most prairie grasses germinate best when seeded in late spring or early summer. Planting at this time also allows for better pre-planting weed control than with fall seeding. Prairies can be successfully seeded from midspring until the end of June. Seeding prairies in the months of July and August is generally not recommended. The remaining growing season is often too short to allow for proper plant establishment prior to winter.
Early Spring - (March - April)
- In general, results in better flower germination than planting in late spring.
- Watering is generally not as critical, as spring rains fulfill this need.
- Warm season grass seed generally has better germination than in fall.
- Best option for sandy soils if unable to plant in fall.
- Limited opportunity for early, cool season weed control.
- Not recommended for heavy soils, as it is difficult to work these soils if wet in spring.
Late Spring - (May - June)
- More time for good soil preparation - particularly important on heavy soils.
- More time for spring weed control prior to seeding.
- Optimal planting time for warm season grasses.
- Increased chance for low moisture conditions later in the season.
- Reduced germination of some flower species.
Fall Seeding - (Sept. 1 up to soil freeze-up)
Fall Seeding can also be very successful, especially on dry soils. Prairies can be seeded from early September until the soil freezes. Fall plantings are “dormant seedings.” The native seeds will not germinate that fall, but will overwinter in the soil and germinate the following spring. This is particularly beneficial when seeding on dry sandy or rocky soils. The seeds will germinate in early spring when soil moisture is abundant and become established before the heat of summer.
Clay soils can also benefit from fall seedings. Clay is often wet and difficult to work in spring. Fall-plantings on clay soils allow the seedlings to become established earlier in spring, before the clay dries out and restricts downward root growth. As with all prairie plantings, weeds must be completely eliminated prior to seeding. Most wildflowers exhibit higher germination rates in spring when fall seeded. Warm season prairie grasses typically show lower spring germination rates with fall seeding.
- Seed over winters as it would in nature and comes up in spring on its own schedule when conditions are right. This breaks most seed dormancies naturally over winter.
- In general, flower species exhibit increased spring germination with fall seeding.
- Recommended for droughty, sandy soils because seed germinates earlier in the season, when moisture levels are optimal, and before summer heat.
- Recommended for clay soils, as clay is easier to work in the fall than in spring, and seeds will germinate earlier in the season. Clay soils often remain wet well into the spring, and by the time they can be safely worked, the heat and drought of summer are often right around the corner. Fall seeding on clay soils encourages earlier germination and better root development prior to the onset of summer.
- Warm season grass seed typically exhibits reduced germination.
- There is no opportunity for early spring weed control by cultivation or herbiciding.
- Be careful on erosion-prone sites. Plant fall seedings no later than September, with an annual rye or oats nurse crop to help hold the soil over the fall and winter.
Fall Seeding on Erosion-prone Sites
Fall seeding on erosion-prone sites requires including a nurse crop for soil stabilization. Nurse crops of annual rye (15 lbs. per acre) or oats (128 lbs. per acre = 4 bushels per acre) must be planted by mid to late September to grow sufficiently to form a protective cover for the soil. The nurse crop will usually be winter killed, but the dead roots will continue to hold the soil over winter until spring when the prairie seeds germinate. Steep slopes should be covered with a light duty erosion control blanket containing either straw or a light layer of excelsior staked into place.
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