How to Prevent Weeds from Growing in New Sod [7 Tips]

To stop weeds from invading your new sod, you should first prepare your yard by spraying a weed and grass killer. Once the weed killer spray has had enough time to work, remove the old lawn with a sod cutter. Then, till your soil to break up any weed and grass roots. This may bring dormant weed seeds to the surface, so it’s best to water your lawn for 2–3 weeks, then spray it with a second dose of weed killer to wipe out new weeds. Once this is complete, you can install your sod. Water your sod to prevent it from shrinking and pull out any weeds by hand. Do not use pre-emergent herbicide or post-emergent herbicide if your sod is less than 4 weeks old.

Is it Normal to Have Weeds in New Sod?

It is not typical to have weeds growing in your new sod. Reputable sod farms grow weed-free sod. In most cases, weeds in new sod sprout from seeds blown onto your lawn. Another way weeds grow in new sod lawns is when weeds sprout from the soil beneath your sod. The weeds then grow up through the seams between the pieces of sod.

• It is uncommon to have weeds in new sod.
• High-quality sod farms grow weed-free grass.
• Most weeds in sod come from seeds present in your yard.
• Weed seeds in the soil beneath sod can grow through sod if your yard is not properly prepared before sod installation.
• Weeds are more likely to invade weak or struggling sod.

In order to prevent weeds from growing in new sod, the most important thing to do is to take steps to get rid of weeds before laying new sod. By ensuring your lawn is weed-free prior to laying sod, you set the groundwork for a healthy lawn without having to battle broadleaf and grassy weeds.

7 Ways to Keep Weeds Out of New Sod

Weeds can ruin the appearance of your new lawn. However, if you take the right steps before laying sod, you’ll set the groundwork for a sod-free lawn. Once your sod is installed it’s essential to provide plenty of water and nutrients so your sod grows deep roots and resists invasive weeds. Here’s how to do it:

Kill Weeds Before Installing Sod

Before you order any sod, begin by spraying weeds in your lawn with a post-emergent herbicide. Systemic herbicides, such as Roundup, are great for this task. However, you can use an organic weed killer instead. Since you will be removing your existing lawn to install your new sod, you can spray all the weeds and grass in your yard if you wish.

• Spray all visible weeds in your yard with a post-emergent weed killer.
• This Roundup weed killer is a great choice for killing weeds before laying sod.
• Instead of a chemical weed killer, you can use this organic weed killer made with citrus oil.
• Allow a full 14 days for weed killer to work before moving to the next step.

Once you spray the weeds with herbicide, allow 14 days for the weeds to fully die. It’s also important to wait this long so that there is no lingering herbicide in the soil. Laying sod on a yard that has recently been treated with weed killer can harm your new sod.

Remove Old Weeds and Grass

Before you can install new sod, it’s essential to get rid of old plant material. Even if the old weeds and grass in your lawn are dead, your sod won’t be able to take root if there’s a layer of plant material beneath the sod. So, it’s essential to use a sod cutter to remove your old lawn.

• Rent a sod cutter to remove old grass and weeds.
• Sod will not take root if it is laid on top of old grass, regardless of whether the grass is living or dead.
• Using a sod cutter physically removes weeds, make it far less likely they will survive and sprout through new sod.

Old sod removed with a sod cutter can be rolled up and taken off your lawn. It can then be thrown away or composted. By removing old grass and weeds with a sod cutter you simultaneously get rid of weeds that may sprout through your new sod and help your sod take root faster. The healthier your sod is, the better it will resist weed invasion.

Till the Soil

Once you have removed your old lawn with a sod cutter, it’s time to till the soil. A motorized rototiller is the best tool for the job. You can rent one from most hardware stores. Use the tiller to loosen the soil to a depth of 6 inches (15 cm). This will break up weed and grass roots, preventing weeds from growing back. It will also loosen the soil, making it easier for your new sod to take root faster.

• Rent a rototiller to till the soil in your yard to 6 inches (15 cm) depth.
• Tilling soil destroys weed and grass roots in the soil, resulting in fewer weeds.
• By tilling your soil, you ensure your new sod takes root faster and can resist weeds.

Tilling is one of the most essential steps to prepare your lawn for new sod. Sod laid on top of untilled soil struggles to take root and is prone to drying out. If your sod struggles, then it’s much easier for weeds to invade.

Water, Wait, and Kill New Weeds

Although tilling has a lot of benefits, it has one downside—it churns the soil and can bring dormant weed seeds to the surface. This can set the stage for a future weed crop that invades your grass. In order to prevent this, water your tilled lawn 2–3 times per week for 2–3 weeks. Then, spray any weeds that sprout with a second dose of the weed killer used in Step 1.

• Tilling the soil can bring dormant weed seeds to the surface.
• Water your tilled lawn for 2–3 weeks, until weeds begin to appear.
• Repeat step 1 and spray the new weeds that have sprouted.

After you perform this second weed spray, wait 14 days for the weeds to die. This step is often skipped in sod preparation but taking the time to encourage weed seeds to sprout, then killing them can work wonders. It will prevent weeds from growing up through your sod in the future.

Set Your Sod up for Success

Once you’ve killed all the weeds in your tilled yard, it’s essential to make sure your lawn is ready for new sod. Leveling and grading your yard is important, and you may even need to add a mix of compost and topsoil to create a smooth surface. Then, it’s time to fertilize your lawn before installing sod. Use a fertilizer designed for new lawns. Spread it on the bare ground before installing your sod.

• Add a starter fertilizer to tilled, leveled, and prepared soil before laying sod.
• This fertilizer is excellent for new sod lawns.
• Fertilizer in your topsoil will encourage your sod to grow faster and resist weeds.

Follow the product label directions on the fertilizer bag to spread the right amount of fertilizer per square foot. Adding fertilizer on top of your soil gives your sod an instant boost as soon as you install it. This results in a lush, thick yard that chokes out weeds.

Keep Sod Moist

Once you’ve installed your sod on top of the fertilized ground, it’s important to provide it with adequate water. Dry sod will shrink, forming cracks between individual pieces of sod. These gaps are where weeds are likely to grow. They will sprout up between your sod. The best way to water new sod is:

• Water your new sod for 10 minutes immediately after installation.
• For the first 2 weeks, water your new sod 2 times per-day (in the morning and late afternoon).
• Each twice-daily watering session should be 10 minutes long.
• After 2 weeks, reduce to one 20-minute watering per day, preferably in the morning.
• After 4 weeks, reduce to twice-weekly watering sessions, 30–60 minutes long.

This watering system for new sod keeps grass moist until it gets a foothold and then gradually reduces the watering frequency. By following this method your sod won’t dry out. It will also be encouraged to develop strong roots. This is essential for stopping weeds in sod.

Avoid Herbicide for the First Month

If you spot weeds growing through your new sod, don’t reach for the weed spray. New sod is delicate and can be harmed by both post-emergent and pre-emergent herbicides. Instead, it’s best to keep a close eye on new sod. If possible, remove any weeds by hand. This will protect your new grass during its early stages.

• If your sod is less than 4 weeks old, remove weeds by hand-pulling.
• Do not treat new sod with herbicide sprays.
• When your sod is 4–6 weeks old, you can begin using weed killer sprays to treat invasive weeds.
• Only use a selective weed killer that is safe for your grass type.

Once your sod is 4–6 weeks old you can begin using weed killer sprays to treat lawn weeds. However, it’s important to choose a spray that is designed for your type of grass. Check product labels carefully and use only selective herbicides that do not harm grass. Roundup is not a good choice since it is a non-selective herbicide that will attack your sod along with the weeds.

Can You Put Crabgrass Preventer on New Sod?

Do not apply crabgrass preventer to new sod. Crabgrass preventer, also known as pre-emergent herbicide, can hinder new sod from taking root. Delay all pre-emergent herbicide applications for at least 6 weeks after laying sod. For more information, check out our article on why you should not apply crabgrass preventer to new sod.

How to Stop Weeds From Coming Up Through New Sod

The best way to keep your new sod weed-free is to follow these steps for sod installation and care:

• Spray the weeds in your yard with weed killer and wait 14 days.
• Use a sod cutter to remove old grass, broadleaf weeds, and grassy weeds.
• Till the soil to a depth of 6 inches (15 cm).
• Water your lawn for 2–3 weeks, until new weeds sprout. Then, spray those weeds with weed killer.
• Finish soil preparation and treat your topsoil with a sod starter fertilizer.
• Install your sod and water it twice per-day for the first 2 weeks.
• Hand pull weeds for the first 4–6 weeks after laying sod. Using weed killer too soon can harm sod.

By taking the time to remove weeds before you lay sod, you’ll ensure a weed-free lawn. If weeds do crop up in your sod, be gentle. Remove weeds through hand weeding. Sod that has been laid in the last 4–6 weeks is too delicate to be treated with weed killer sprays.