Should I seed before or after I mow?

When it comes to lawn care, one of the most common questions homeowners have is whether they should seed their lawn before or after mowing. Both approaches have their pros and cons, and the right timing depends on factors like the type of grass, time of year, and condition of your yard.

In this comprehensive guide, we’ll walk through the key considerations around seeding before vs after mowing, so you can determine the best approach for your specific lawn.

Table of Contents

Should I Seed Before Mowing?

Seeding before mowing has a few potential advantages:

Mowing after seeding can cover grass seeds with a thin layer of grass clippings and soil, helping keep seeds in place and protected.
Mowing after seeding also clears away thick patches of old growth, allowing more sunlight to reach newly planted seeds.
If you scalp or dethatch before seeding, mowing after can tidy up the lawn and evenly distribute any remaining debris.

However, there are also some potential drawbacks to seeding before mowing:

Mowing too soon after seeding could sweep away some of the freshly distributed seeds before they have time to root.
If the lawn is mowed too short after seeding, it may be prone to drying out in hot weather.

Taller grass prior to seeding provides more shade and moisture for newly planted seeds.

Should I Mow Before Seeding?

Mowing before seeding offers some advantages as well:

Mowing first allows you to cut the existing lawn down to the optimum height for seeding, typically around 2-3 inches.

It removes any thick or matted grass layers that could obstruct seed-to-soil contact.
Mowing first can eliminate tree leaves, debris, or dead grass that could interfere with seeding.

However, there are some potential cons to mowing before seeding:

Exposing bare soil may increase evaporation, requiring more frequent watering of newly planted seeds.
Without grass blades to trap them, seeds may be more easily blown or washed away.
Freshly cut grass can form a mat on top of the soil, making it harder for seeds to work their way into the soil.

Key Factors in Deciding When to Seed vs Mow

When choosing the best time to seed in relation to mowing, there are several important factors to consider:

Time of Year

Cooler fall temperatures are optimal for seeding, as seeds germinate best at soil temperatures between 60-75°F. Seeding in fall allows new grass to mature over winter and root deeply come spring.

Seeding in the summer raises challenges like scorching sun, weed pressure, and a need for constant hydration of new seeds. However, with proper care summer seeding can still succeed.

In spring, competition from crabgrass and other weeds can complicate seeding. Overseeding thin summer grass in spring is an option, but avoid heavily disturbing the soil then.

Grass Type

Spreading grasses like Bermuda self-repair bare spots, making periodic overseeding unnecessary. Meanwhile, bunch grasses like fescue require regular seeding to fill in clumps.

Fast-growing annual ryegrass establishes quickly for fast cover, while slower perennials like Kentucky bluegrass provide long-lasting turf but are slower-growing when seeded.

Soil and Climate Conditions

Sandy, porous soils may require seeding before mowing to retain moisture, while heavy clay soils could benefit from mowing first to open up the ground and improve seed-to-soil contact.

In dry climates with less rainfall, mowing after seeding helps preserve ground moisture. Wetter regions can support mowing before seeding to open up the lawn.

Condition of Existing Turf

On lawns with thick, healthy turf, mowing first helps thin layers for better seeding access. For lawns growing in patchy or on mostly bare soil, mowing after seeding is preferable to stabilize seeds.

Lots of dead grass or debris benefits from mowing first. Overgrown but sparse lawns combine mowing first with aeration to open up the ground before seeding.

Best Practices for Seeding Before Mowing

If you opt to seed before mowing, here are some tips for success:

Mow existing turf down to 2-3 inches before seeding so grass blades don’t completely obstruct seeds.

Use a power rake lightly before seeding to expose some bare soil while retaining grass coverage.
Water newly planted seeds for 10-14 days until established roots form before mowing.
When mowing, use a high cut height setting to avoid disturbing seeds. Remove no more than 1/3 of the grass blade length.

Cover seeded areas with straw to reduce evaporation and protect tender new shoots after mowing.

Ideal Times to Seed Before Mowing

Fall – cooler temperatures and occasional rain help seeds thrive
Early spring – some moisture remains from winter and snowmelt

Summer – requires meticulous hydration of seeded areas in heat

Best Practices for Mowing Before Seeding

If mowing before seeding, keep these tips in mind:

Scalp or dethatch lawn first to expose maximum bare soil for seed-to-soil contact.

Mow as low as 1 inch in height, or even aeration alone for very short lawns like Bermuda.
Water newly seeded areas daily in short bursts to keep seeds moist without puddling or runoff.
Consider covering seeded areas with peat moss or straw to retain moisture after planting.

Wait until new grass reaches 3 inches tall before mowing again.

Ideal Times to Mow Before Seeding

Late summer when reducing grass height prior to fall overseeding
Spring once soil has thawed and dried out from winter

Fall on lawns with thick mats of grass that need thinning

Key Tips for Success Seeding Either Before or After Mowing

Whichever order you choose to seed and mow, adhere to these tips for the best results:

Always mow with sharp blades to avoid tearing grass blades.

Change mowing patterns between seedings to avoid soil compaction in one area.
Seed in two perpendicular passes across the lawn, once north-south and again east-west.
Use spreader setting for smallest seeds to ensure even distribution.

Gently rake seeded areas to settle seeds into soil.
Water newly planted seeds daily until established (10-14 days).

Should I Mow Newly Seeded Grass?

It’s best to allow newly seeded grass to grow to around 3 inches tall before mowing for the first time:

Mowing too soon risks pulling up tender new shoots.
Allowing new grass to mature helps the roots establish deeper into the soil.
With adequate water, new grass can reach 3 inches within 2-3 weeks of sowing seed.

When mowing new seedlings for the first time:

Set mower height to the highest setting to simply trim the tops of new growth.
Remove no more than 1/3 of the grass blade length at a time.

Use a push mower gently on new grass to avoid tearing or damaging the emerging lawn.

Overseeding an Existing Lawn

When overseeding a thin but existing lawn:

Mow first to open up the turf for maximum seed-to-soil contact.

Use a power rake to lightly dethatch without scalping completely to the soil.
Apply starter fertilizer when seeding to support new growth without forcing mature grass to grow faster.
Consider mixing seed types, like adding fine fescues to complement existing taller grasses.

Ideal times to overseed are early fall when temperatures cool or early spring before summer heat arrives.

Tips for Seeding a Completely New Lawn

For establishing grass where no lawn currently exists:

Eliminate all existing vegetation through smothering or herbicide treatment.

Till soil to a depth of 6-8 inches to loosen and prepare the seedbed.
Grade and level the seedbed area for even drainage.
Apply starter fertilizer to low levels to encourage root growth.

Lay sod or seed thickly for complete coverage according to label rates.

The ideal time to seed a new lawn is early fall when the weather supports optimal germination.

Should I Fertilize When Seeding?

Fertilizer can support germination when seeding but isn’t strictly necessary in many cases:

Existing lawns often have adequate nutrients for new grass seeds to establish.
Starter fertilizer provides a boost by supplying phosphorus for root growth.
Too much nitrogen fertilizer can cause rapid top growth and compete with new seedlings.

When overseeding, apply starter fertilizer carefully only to seeded areas instead of entire lawn.

Slow-release organic fertilizers provide a gentle nutrient source for establishing new seeds. Avoid weed and feed products when seeding.

How Much Seeding Is Needed?

Most grass seeds specify a recommended seeding rate on the packaging (such as 5-8 lbs per 1,000 sq ft). A general guideline is:

New lawns: 8-10 lbs per 1,000 sq ft
Overseeding thin lawns: 5-8 lbs per 1,000 sq ft
Spot seeding bare patches: 2-3 lbs per 1,000 sq ft

When in doubt, add extra seed – it won’t hurt to have slightly thicker turf. Prioritize proper seed-to-soil contact over precisely measuring seed quantities.

Conclusion

The decision of whether to seed before or after mowing depends on multiple factors like grass type, time of year, and current state of your lawn.

For the best results, tailor the timing to your unique conditions. Adhere to best practices in soil preparation, seeding depth, and watering to support the germination and growth of new grass.

With the right timing and care, you can fill in bare spots or establish a lush new lawn by effectively coordinating seeding and mowing.

Time of Year	Recommendation
Spring	Mow first to remove debris then seed
Summer	Seed first then mow gently after 2 weeks
Fall	Can mow first or after – optimal time for both