Will grass seed stay dormant until spring?

Many gardeners wonder if grass seed they plant or sow in late fall or winter will stay dormant until spring. Understanding the germination and dormancy cycle of grass seed can help ensure successful lawn establishment.

Quick Answers

– Most grass seed varieties require soil temperatures above 50-55°F for germination. In colder climates, this usually doesn’t happen until spring.

– Some newer grass seed varieties are bred to germinate at lower soil temperatures, even as low as 40°F.

– Dormant seeding in fall can still be successful if soil prep, timing, seed to soil contact and irrigation are optimal before cold weather sets in.

– While seed may remain viable over winter, germination and establishment rates are lower with dormant fall seeding compared to spring.

– Use of seed blankets or other protection methods may help improve dormant seeding success.

– Spring seeding when soil temperatures are consistently above 55°F is recommended for best germination and establishment results.

Grass Seed Germination Requirements

For grass seed to successfully germinate and grow, there are three key requirements:

  • Proper soil temperatures
  • Adequate moisture
  • Good seed to soil contact

Most common cool season grass varieties such as Kentucky bluegrass, perennial ryegrass, and tall fescue require soil temperatures of at least 50-55°F for vigorous germination and growth. Some newer variety grasses are bred to germinate at slightly lower soil temperatures down to 40°F.

Warm season southern grasses like Bermuda grass, zoysia grass, centipede grass, and St. Augustine grass require much warmer soil temperatures of 65-70°F for germination.

Soil Temperature Requirements by Grass Type

Grass Type Minimum Soil Temperature for Germination
Kentucky Bluegrass 55°F
Perennial Ryegrass 45°F
Tall Fescue 45°F
Fine Fescue 45°F
Bermuda Grass 65°F
Zoysia Grass 65°F
St. Augustine Grass 65°F
Centipede Grass 65°F

These soil temperature requirements explain why cool season grasses perform best when seeded in spring and fall when temperatures are moderate, while warm season grasses grow best seeded in late spring and summer when it’s warmer.

Dormancy Mechanisms in Grass Seed

Grass seed can remain dormant or inactive for long periods when conditions are unfavorable for germination and growth. Dormancy prevents premature germination during stressful periods of heat, cold, or drought that would kill young grass plants.

Seed dormancy is enforced through one or more of these mechanisms:

  • Physical dormancy – Water cannot penetrate the seed coat to initiate germination.
  • Physiological dormancy – Biochemical or hormonal conditions in the seed prevent germination.
  • Morphological dormancy – The embryo in the seed is not fully developed and cannot yet grow.

As seasons change and growing conditions improve, dormancy is broken naturally through weathering processes like moisture, freezing and thawing, or microbiological activity in the soil. This allows the seed to germinate when circumstances become favorable again.

Challenges of Dormant Fall Seeding

Dormant seeding, or planting grass seed in late fall heading into winter dormancy, can be done but is riskier and less successful than spring planting. Here are some of the challenges:

  • Colder soil temperatures inhibit germination until the following spring.
  • Freezing and thawing over winter can displace seeds and break contact with soil.
  • Heavy rains can cause seeds to wash away before germinating.
  • Less daylight and warmth means slower growth even if seeds germinate.
  • Weed pressure is greater in spring before grass establishes.
  • Seed is more prone to rotting, disease, and animal predation over an extended dormant period.

For these reasons, grass seeding when soils are cold rarely achieves more than 30-50% germination rates compared to 80% or better in spring. However, fall dormant seeding can still fill in bare spots ahead of spring.

Improving Results of Dormant Fall Seeding

If seeding grass in late fall, there are a few tips to help improve success:

  • Use newer grass varieties bred to germinate at cooler temperatures as low as 40°F.
  • Prepare soil, remove debris, and rake level to enhance seed-to-soil contact.
  • Seed early enough before ground freezes to allow roots to anchor.
  • Cover seeded areas with straw to insulate soils during winter months.
  • Consider erosion control blankets or turf blankets to protect seeds.
  • Water thoroughly after seeding and keep soils moist until ground freezes.

With extra care taken to maintain consistent moisture and maximize seed-to-soil contact, you may achieve 50-75% germination from fall dormant seeding. This can provide partial cover and reduced erosion over winter.

Spring Seeding for Best Results

For optimal germination rates and grass establishment, it’s best to wait until spring when soil temperatures rise above 55°F and all risk of frost has passed. Spring offers the most favorable growing conditions for grass.

The steps for successful spring seeding include:

  1. Test soil pH and nutrients and amend as needed.
  2. Eliminate existing weeds through spraying or tillage.
  3. Break up compacted soils and smooth grading.
  4. Spread seed evenly ensuring good soil contact.
  5. Cover lightly with 1⁄4” layer of soil or peat moss.
  6. Water gently daily to maintain moist soils until sprouting.
  7. Apply starter fertilizer when grass reaches 2-3” height.

Following proper practices for spring seeding avoids the risks and limitations of dormant fall seeding. Germination rates over 80% are normal with spring planting.

Let’s compare spring and fall grass seeding:

Factor Spring Seeding Fall Dormant Seeding
Soil Temperature Warmer – Favorable for germination Colder – Less germination
Moisture Natural rainfall more reliable Need to irrigate until frost
Weed Pressure Less competition from weeds More weeds in spring
Seedling Survival High rates in ideal conditions Lower rates through winter stress
Root Establishment Rapid growth in warming soils Slowed by cold soils
Time to Maturity 6-8 weeks 10-12 weeks
Overall Germination Rates 80% or higher success 30-50% success

This comparison shows why most experts recommend spring over fall seeding if the highest success and germination rates are desired.

Testing Seed Viability After Winter

If you do attempt dormant fall seeding, it’s smart to test seed viability again in spring after subjecting seed to many stresses over the winter. Simple at-home methods include:

  • Paper towel germination test – Place seeds between moist paper towels to look for sprouting.
  • Clear glass observation – Put seeds in a clear glass with water to monitor growth.
  • Dig up seeds – Check a few planted seeds to see if swollen, split or sprouting.

Checking seed viability this way allows you to determine if another round of spring overseeding is needed to thicken up patchy areas.

Using Dormant Seeding in Lawn Renovation

Dormant fall seeding can play an important role when renovating or establishing a new lawn. The process typically involves:

  1. Kill existing grass and weeds with non-selective herbicide.
  2. Dormant seed with hearty tall fescue in fall.
  3. Overseed again with bluegrass in spring to thicken lawn.
  4. Fertilize and water appropriately for lush growth.

The fall fescue provides partial winter ground cover and stability. The spring bluegrass offers maximum germination for summer beauty and durability. Combining both periods takes advantage of their strengths.

Fall Renovation Timeline

When planning a full lawn renovation, the fall timeline would be:

  • Early September: Kill existing lawn with non-selective herbicide like glyphosate.
  • Mid September: Dethatch, aerate and amend soils if needed.
  • Late September/Early October: Seed with turf-type tall fescue blend.
  • November: Continue watering until ground freezes.

This allows time for fescue to establish before winter dormancy. Then complete spring overseeding when soil temperatures allow.


Understanding the germination requirements of different grass seeds helps properly time planting. While technically possible to dormant seed in fall, spring seeding offers far better results in growth, germination rates, and weed resistance.

Use dormant fall seeding primarily when renovating lawns or repairing bare patches ahead of winter. Combine with spring overseeding for maximum quality and durability. Testing seed viability after winter dormancy can indicate if added seeding is beneficial.

With the right timing and care for seasonal conditions, you can successfully establish lush, healthy grass. Learn your climate patterns, soil conditions, and grass species traits for lawn success.

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