When to Seed

Most native perennial wildflower seed does best sown in late fall, but dormant (winter) and spring seedings can both succeed. Each window comes with trade-offs, so weigh the species in your mix, the conditions on your site and your project schedule before ruling any of them out.

Fall and winter seedings let nature do much of the work: cold, moist weather breaks seed dormancy, and freeze–thaw cycles help settle the seed into the soil. Spring seedings give you more control over weeds right before sowing, but they rely more heavily on irrigation and may call for seed that’s been pre-treated. The comparison below sets out the advantages and drawbacks of each window.

Fall

September until the soil freezes

Advantages

  • It mimics the way seed drops naturally.
  • Seed gets natural cold-moist stratification over winter, which improves germination.
  • Higher soil moisture means less watering.
  • Seed-to-soil contact is better.
  • Cool-season grasses germinate and establish strongly over winter.
  • More forbs and sedges germinate in the first growing season.
  • Clay soils are easier to work.

Drawbacks

  • There’s less opportunity for early-spring weed control.
  • Mulch is needed to protect the seed and hold moisture.
  • Some seed is lost to wildlife and decay over winter.
  • Most germination waits until spring, when the soil reaches about 55°F.
  • Warm-season grasses may be slower to establish.
  • Cool-season weeds can compete with seedlings in spring.

Winter

Dormant or frost seeding, December to March

Advantages

  • Freeze–thaw cycles gradually work the seed into the soil, so there’s no need to roll or rake after sowing.
  • High soil moisture means less watering.
  • Seed gets natural cold-moist stratification.

Drawbacks

  • Seeding has to wait for snow-free periods.
  • Erosion-prone sites may need a cover crop sown before the native seed.
  • Warm-season grasses may be slower to establish.
  • Cool-season weeds can compete with seedlings in spring.

Spring

April to June

Advantages

  • Less seed is lost to wildlife and decay.
  • Cool-season grasses germinate soon after seeding.
  • Cool-season weeds are easy to clear right before seeding, giving you more control over competition.

Drawbacks

  • Species that need stratification may be slow to germinate unless the seed is pre-treated.
  • Dry spells mean considerably more irrigation than a fall or winter seeding needs.
  • Clay soils are harder to work.
  • Seeding can be delayed while weeds are brought under control.
  • Good seed-to-soil contact is harder to maintain.

Seeding in spring?Check the seed treatment listed on each species page. Seed that needs cold-moist stratification can be pre-treated before sowing so it germinates the same season, and the germination guide explains how.