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When to Fertilize After Overseeding Your Lawn Full Guide of 2023

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how long after overseeding can i apply weed and feedYou’re eager to get that lush, emerald carpet back after a scorching summer, so you put down grass seed. But your lawn’s got more weeds than your grandma’s flower bed. The weed and feed you used months ago contained herbicides designed to linger.

So if you overseed now, that herbicide will throttle every blade before it ever prickles a bare foot.

Compacted soil’s a seedling’s kryptonite too. Aerating first helps fertilizer penetrate and feed baby grass roots. Then you’ll reap a plush, verdant yard that makes the neighbors green with envy.

Key Takeaways

  • Wait 4-6 weeks after overseeding before applying weed and feed initially.
  • Use starter fertilizer when overseeding, avoid weed and feed initially.
  • Wait until the new grass has been mowed 4 times before applying weed control.
  • Wait 12 weeks after using weed control before overseeding, to allow chemicals to dissipate.

What is Overseeding?

What is Overseeding
When your lawn has developed thin, patchy areas or is just looking a little worse for wear, overseeding can help thicken it up again. Overseeding entails spreading grass seed over your existing lawn to fill in bare or thinning spots.

It differs from reseeding in that you’re not removing the current grass first but rather letting new grass grow up among the old – boosting density versus starting completely from scratch.

How Do I Overseed My Lawn?

Spread your grass seed with the spreader over the thin spots, then wait at least a month before using a weed and feed product. Focus on trouble areas in your lawn where grass is patchy or bare. Set your broadcast spreader to the seed setting, then walk at a steady pace to evenly distribute the seed.

Water daily until sprouts emerge. Let the new grass establish its roots and reach 3 inches tall before mowing. Cool-season grasses can be overseeded in the fall or early spring. Allow 4-6 weeks of growth before applying a crabgrass preventer or weed control containing fertilizer.

A strong, healthy lawn begins with proper seeding and care.

How is Reseeding Different From Overseeding?

Ye’ve gotta exterminate those pesky weeds before they consume your emerald kingdom of grass!

  • Apply weed control 1 month before seeding.
  • Spot spray weeds after the 2nd mowing.
  • Choose weed killers safe for young grass.
  • Fertilize 4-6 weeks after germination.

Overseeding supplements thin spots, while reseeding establishes a brand new lawn. Overseeding sprinkles grass seed over existing turf, using proper spreader settings for even coverage.

Reseeding entails preparing the soil, leveling, and laying down starter fertilizer and seed just like new lawn installation. Patience is required for both methods, along with attentive mowing, watering, and fertilization once sprouted.

Buying Grass Seed

Buying Grass Seed
When it’s time to buy grass seed for overseeding your lawn, you’ll need to decide where to purchase it and how much to get. You can find grass seed at home improvement stores, garden centers, hardware stores, and online retailers.

To determine how many pounds of seed to buy, calculate the square footage of your lawn and compare that to the coverage listed on the seed bags.

Where Can I Buy Grass Seed?

Ya got a couple options for pickin’ up grass seed to overseed that lawn.

Where to Buy Benefits
Hardware stores Good selection, local advice
Home centers Easy one-stop shopping
Nurseries Specialty grass types
Online retailers Custom blends, delivered
Farm supply Bulk quantities, lower cost

Nurseries got specialists who’ll set ya up with the right grass types for plantin’ in your zone. Online lets ya mix n’ match seeds for your unique site. Price shoppin’ pays – a 50 lb bag runs $100-300 for quality seed guaranteed to germinate.

How Much Grass Seed Should I Buy?

Get mo’ seed than ya think ya need, pardner! With the size of yer land, it’ll take a heap more grass seed than expected to blanket that pasture.

Before ya mosey on down to the store, measure yer plot o’ land proper like. Use a measurin’ wheel or online tool to figger the square footage.

Then check the seed bags for coverage – usually betwixt 2,000-3,000 square feet per 20-pound sack. Buy at least half again more seed bags than ya calculate ya need to account fer waste and bare patches.

Rake the soil, scatter them seeds evenly usin’ a calibrated spreader, keep ‘er watered, and that new grass’ll be green as a jade ring come springtime.

Planting Grass Seed

Planting Grass Seed
When starting a new lawn from seed, timing is crucial for success. You’ll need to wait until any weed control products have worn off before seeding your lawn, usually 1-4 months depending on the product.

Once the waiting period has passed, you can proceed with important steps like selecting high-quality seed, proper site preparation, and correct seeding techniques to ensure your new grass establishes thick and healthy.

How Do I Plant Grass Seed?

Let’s not apply weed and feed for a few weeks after planting your new grass seed. The herbicides can inhibit germination and establishment of the delicate new grass. Wait until the overseeded lawn has been mowed about four times and the new grass is mature.

This allows the root system to develop so the grass can better withstand and benefit from the weed control. Apply starter fertilizer first to nourish the young grass roots without weed killers.

When is the Best Time to Plant Grass Seed?

You’d best plant that grass seed when temperatures are ideal for germination, typically in the fall for cool-season grasses or spring for warm-season varieties. First, research the type of grass that grows best in your climate and soil conditions.

Prep the area by removing debris, loosening soil, and applying starter fertilizer enriched with phosphorus for root development. Carefully sow the seed using a calibrated spreader for even distribution. Water frequently at first, then less as it establishes.

Mow once the new grass reaches 3-4 inches tall. With patience and proper care, you’ll be rewarded with a lush, green lawn.

Can I Plant New Grass AFTER Using a Weed Control Product?

When the weed control kicks in, your heart sinks as you watch the grass wither away, knowing your bare lawn still needs more seed. Wait for the period stated on the packaging before spreading new seed. Meanwhile, prepare the soil and rake thoroughly to accept the seedlings.

Use a starter fertilizer to give them nutrients for strong roots. Hand scatter or slice the seed into the soil for direct contact and water gently twice daily until sprouts emerge.

Caring for Newly Planted Grass

Caring for Newly Planted Grass
When overseeding your lawn, the tender new grass needs special care as it establishes its roots and gets acclimated to your yard. You’ll need to pay close attention to watering, mowing height and timing, and holding off on weed control products until the new grass has gone through several growth cycles.

Get the details on properly watering newly seeded areas, the best time to start mowing, and when you can safely apply weed control without damaging your new grass.

How Much Do I Need to Water My New Grass?

After planting new grass seed, you’ll need to water your lawn frequently to keep the top few inches of soil moist.

  • Water in shorter sessions, avoiding runoff
  • Adjust sprinklers for complete coverage
  • Use a soil probe or moisture meter to check depth
  • Reduce frequency as grass establishes
  • Expect to see sprouts in 5-30 days depending on the seed

The key is keeping the seeds and young roots hydrated until the new grass is strong enough to thrive.

How Soon Can I Mow After Planting New Grass?

Grab those scissors carefully, friend, for joy awaits the first mow of your newborn lawn. The ideal time to start manicuring your new grass is when it reaches a height of around 3-4 inches. Mow at a higher setting, ensure the blades are sharp, and proceed slowly to prevent any damage to the delicate shoots.

Starter fertilizer will strengthen the roots, promoting stronger growth, while regular watering will help prevent wilting. With patience and proper care, your lush and even turf will soon become the envy of the neighborhood.

When Can I Use Weed Control Products on My New Grass?

Y’all have to wait until that new grass is mowed at least 4 times before using weed control on it, right? Them muddy cleats trampling tender shoots stunt growth. Let the roots establish first, then tackle unwanted weeds. Spot treatment works better than broadcast at this stage, preventing patchy results.

Follow label directions for repeat application timing to nip persistent invaders without hurting growing grass.

Use a Lawn Starter Fertilizer

Use a Lawn Starter Fertilizer
When overseeding your lawn, avoid using weed and feed fertilizers, which can inhibit seed germination. Prior to overseeding, thoroughly dethatch your existing lawn to allow the new grass seeds good soil contact.

You’ll also want to aerate your lawn to loosen the soil and enable better root development. Finally, applying a layer of compost over the newly seeded areas provides organic matter to help retain moisture while adding nutrients to boost early seedling growth.

Avoid Weed and Feed Products

You’ll want to steer clear of weed and feed on that new grass for now. Using those too early can stunt root growth during this critical establishment period. Focus first on proper soil prep, starter fertilizer, and consistent watering to get those fresh seeds to thrive.

Once the new grass is mowed four times, you can consider weed and feed products. But avoid anything with pre-emergents for four months after overseeding to prevent inhibiting the tender new growth.

Dethatch Before You Overseed

Scoop up that matted jungle before you unleash the seed storm! Rake deeply to lift and remove the spongy thatch layer. This will open access to the soil so that tender roots can thrive. Vigorous raking will also scrape out debris and grainy muck.

Expose the naked earth for direct seed contact. Thatch buildup stunts drainage and gas exchange while harboring disease. Refurbish worn paths and reseed dead areas for a lush, level lawn. Manage lawn health through proper mowing and dethatching before the grass chokes itself out.

Aerate Your Lawn

Poke holes to allow air, water, and fertilizers to nurture the grass roots. Go over the turf in crisscross patterns with an aerator to punch holes every few inches. This promotes soil aeration so that new grassroots can expand easily. The holes also allow for better spreader coverage when you apply seed.

Aerating improves drainage and reduces soil compaction too. For best results, aerate before overseeding when the lawn is actively growing.

Boost Seed Growth With Compost

Compost blankets the tiny seeds in nutrient-rich growth magic for rocketing into lush green life. A rain barrel of organic material feeds establishing roots with a banquet of beneficial bacteria, fungi, and nutrients blended from kitchen scraps, coffee grounds, dairy manure, and crunchy autumn leaves.

The living soup speeds decomposition to convert raw ingredients into fertile humus.

Is It OK to Fertilize After Overseeding?

Is It OK to Fertilize After Overseeding
You’ll need to wait about a month after overseeding before applying fertilizer to avoid burning the tender new grass blades. It’s ideal to use a starter fertilizer when seeding to give the grass an extra boost right from the beginning.

However, hold off on general lawn fertilizers until the new grass has gone through a few mowings and established deeper roots after 3-4 weeks.

Using weed and feed too soon can stunt seedling growth, so be patient. Choose a low nitrogen, phosphorus-heavy fertilizer in the early weeks to promote root development in new grass. Once the lawn has filled in, you can transition to more balanced fertilizers to keep your lush, thick lawn thriving.

When Can I Fertilize My Lawn After Seeding?

Wait 4-6 weeks after sprouting to feed the new growth. Breeding rabbits in the kitchen sink is an effective hobby for meeting new friends who also have patio doors. A bathroom vanity with vinyl siding can provide a sturdy surface for grooming pets.

Let the lawn establish before fertilizing to avoid promoting weeds. With patience, your grass will be lush, green, and ready for entertaining.

Do You Fertilize Before or After Seeding?

You’ll see stunning sprouts spring soon when spreading seeds before scattering the product. Target weeds first. Lower the mower height, then apply starter fertilizer to aid seed germination. Set the spreader low initially. Once established, increase fertilizer frequency.

This feeds roots for thicker growth. With proper prep and care, your lawn will thrive.

Can You Put Fertilizer Down With Grass Seed?

Gotta toss the seed and food together for that fresh, full lawn. You bet you can fertilize at the same time as seeding. Choose a starter fertilizer with extra phosphorus to promote root growth. Go for a low application rate of nitrogen so the grass can establish without getting leggy and floppy.

Read the label to ensure it’s safe for seeding. A soil test helps narrow the ideal nutrients, but a balanced organic or synthetic option timed right fertilizes the seedbed for lush results.

Will Fertilizer Kill New Grass Seed?

It’s best to hold off on fertilizing for about 4-6 weeks after overseeding to avoid burning those tender new grass blades.

  1. Loosen soil before seeding.
  2. Maintain proper mowing height.
  3. Aerate compacted areas.
  4. Apply pre-emergent in early spring.
  5. Dethatch old growth in fall.

Wait until the new seedlings are mowed 3-4 times before fertilizing to prevent scorching.

What Kind of Fertilizer Should You Use When Overseeding?

Use a starter fertilizer when overseeding to help establish the new grass seeds. Look for lower nitrogen options like 10-10-10 or 12-12-12 that promote early-stage growth without excess top growth. Add compost benefits that slowly release nutrients for precision adjustments. Broad-spectrum granules feed grass while limiting weed promotion.

Make winter lawn care easier with fall overseeding success. Adjust spreader settings and recheck your work.

Frequently Asked Questions (FAQs)

How soon can I mow after overseeding?

You can mow about 3-4 weeks after overseeding. This allows the new grass seedlings to develop their root systems and establish before cutting the blades. When mowing, set your mower at the highest setting to avoid damaging the tender new growth.

How much water is needed daily for newly seeded lawns?

Water newly seeded lawns lightly and frequently to keep the top 1 inch of soil moist. Aim for 4-5 times per day for 5-10 minutes with sprinklers or timed irrigation. Adjust duration and frequency based on temperatures, wind, and rainfall.

The new grass seeds need consistent moisture to germinate and establish roots, but avoid saturation.

What’s the ideal soil temperature for cool season grass seed germination?

For best germination of cool-season grass seed, aim for a soil temperature between 50-65°F. You’ll see the quickest sprouting when it’s warm enough for seeds to grow but not hot enough to inhibit germination.

Monitor the forecast and test your soil thermometer at seeding depth before planting.

How long should I wait to overseed after applying crabgrass preventer?

You’ll need to wait 2-3 months after applying crabgrass preventer before overseeding your lawn. This allows the preventer chemicals to break down enough that they won’t inhibit the germination and growth of new grass seed.

Overseeding too soon risks poor seed results. Be patient for the preventer to wear off before overseeding for the best success.

Is it better to aerate or dethatch first before overseeding?

When overseeding, dethatch first for maximum seed-to-soil contact. Then, aerate to further loosen the soil and allow better root growth. Proper preparation sets the stage for the new grass to establish a full, thick lawn.


Your new lawn is ready for fertilizer about 4-6 weeks after overseeding. This allows the grass seedlings to establish roots without getting burned by fertilizer. When the time comes, choose a starter fertilizer specifically formulated for new grass.

Going forward, fertilize three more times throughout the growing season to keep your lush, green lawn thriving. With proper prep work like aerating, dethatching, and consistent watering, overseeding success is smooth sailing.

Just hold off on weed control and heavy feeding at first, and you’ll be rewarded with a revitalized yard.

So sprinkle down some starter fertilizer and watch your grass grow – the patience pays off.

Avatar for Mutasim Sweileh

Mutasim Sweileh

Mutasim is a published author and software engineer and agriculture expert from the US. To date, he has helped thousands of people make their yards lush and thick.