If weeds are growing up through your new sod, begin by discovering what type of weed is growing there. Grassy weeds like crabgrass must be treated differently than broadleaf weeds like dandelions. Next, uproot weeds by hand if your sod was installed less than two weeks ago, since herbicide sprays can harm new sod. If your sod was installed more than two weeks ago, choose a selective herbicide that kills weeds but does not harm your grass species. Finally, water your sod regularly. This will prevent sod from shrinking, which in turn helps crowd out weeds.
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Why Do Weeds Grow Up Through Sod?
Weeds and crabgrass grow up through new sod for two reasons. First, weeds in the soil beneath the sod can sprout and grow up in the cracks between pieces of sod. Second, some sod may be delivered with weed seeds present in the sod. These seeds sprout and grow on top of your new sod.
- Weed seeds in your topsoil may sprout and grow in the cracks between pieces of sod.
- Sometimes, sod may be delivered with weed seeds on the sod.
- Proper soil preparation can stop weeds from sprouting after you lay sod.
If your sod is delivered with weed seeds already present, there’s not much you can do but battle the weeds as they sprout. However, you can prevent weeds from growing up through your new sod by properly preparing the soil before sod planting. This will drastically reduce the number of weeds you have to remove from your new lawn.
How Soon Can You Treat New Sod for Weeds?
Wait at least two weeks after installing sod before you spray the sod for weeds. Spraying sod with any weed killer too soon can damage or kill your sod. This is because new sod is very fragile and susceptible to damage in the early stages of life. Once the sod has been in place for two weeks, it will begin to send roots down into the topsoil. Then, you can spray the sod with a selective post-emergent herbicide that kills weeds but won’t harm grass.
- Sod can be sprayed with post-emergent herbicide 2 weeks after installation.
- Do not spray sod that has been installed less than 2 weeks ago—you may kill the grass.
- Do not use pre-emergent herbicides on new sod for 3–6 months.
- Never use Roundup or vinegar weed sprays on sod—these sprays kill grass.
Avoid using pre-emergent herbicides on sod lawns until they have been established for an entire growing season. Using a pre-emergent or “crabgrass preventer” too soon can harm the growth of new sod. It’s also essential to avoid using vinegar sprays, Roundup, or any other non-selective weed killer. These compounds will kill your new grass at the same time they kill weeds.
4 Steps to Kill Weeds Coming Up Through New Sod
Weeds cropping up in your sod can be frustrating and hard to deal with. Sod is delicate, so special measures should be taken when killing weeds so that your lawn is not damaged. Here’s how to kill weeds in sod and promote a healthy lawn.
Identify the Weed Type
Before you can attack the weeds that are invading your sod, you have to know what type of weeds you’re dealing with. There are two main types of weeds: grassy weeds and broadleaf weeds. Grassy weeds include crabgrass, orchard grass, and all other pest grasses. Broadleaf weeds are non-grassy weeds. Common examples include clover and dandelions.
- Inspect the weeds growing in your new sod and try to identify them.
- You don’t need to be a plant expert—begin by trying to determine if the weeds are pest grasses or broadleaf weeds (such as dandelions and thistles).
- Grassy weeds and broadleaf weeds require different weeding sprays, so identification is a key step.
The reason it’s essential to know what type of weeds you have in your sod is because weed sprays that kill broadleaf weeds often don’t kill grassy weeds, and vice-versa. Once you know what sort of weeds you’re fighting, you’ll be able to choose the correct weapons to use against them.
Because new sod can easily be damaged by weed sprays in the first two weeks after installation, it’s best to remove the weeds by hand if possible. This eliminates the risk of harming your sod with herbicides. Grasp weeds by the base to pull them up by the roots, or use a weeding tool to fully remove the weeds.
- Use this weeding tool to remove weeds down to the root without harming your sod.
- Hand-weeding works to kill all weeds, regardless of type.
- Because it involves no chemicals, hand-weeding protects new sod lawns.
Removing the weed and its root by hand works against all types of weeds. It also kills weeds instantly, so there’s no need to spray and wait for results. As long as your lawn is not overrun with pesky weeds, it’s best to hand-weed your sod to keep your grass as healthy as possible.
Spray for Weeds
If weeds have overtaken your lawn and hand weeding isn’t a viable solution, it’s time to invest in a grass-safe weed spray. The exact spray you choose depends on the grass species in your lawn. Herbicide that kills everything but Bermuda grass is great for Bermuda lawns, but may damage other grasses. So, it’s essential to choose a post-emergent, selective herbicide that attacks weed species, not your grass.
- You can spray post-emergent herbicide on your sod lawn if it was installed at least 2 weeks ago.
- Consult with an expert at your lawn and garden center to choose a herbicide that will kill the invading weeds without hurting your particular type of grass.
- Do not put pre-emergent or “crabgrass preventer” products on your sod lawn for 3–6 months after installation.
2,4-D is a great choice for killing broadleaf weeds in most lawns without harming your grass. However, grasses such as St. Augustine and Centipede grass can be damaged by 2,4-D applications. When choosing a weed killer for your lawn, it’s best to ask for help from a professional at a lawn care or home & garden center. Let them know what grass type you are growing and what weed types you’re looking to kill. They can guide you to the best product for your lawn.
Water Sod to Choke Out Weeds
New sod needs plenty of water to resist shrinkage, stay green, and develop into a self-sustaining yard. A lack of water causes sod to dry out and shrink, which allows weeds to grow in the widening cracks between sod pieces. Struggling sod also allows weeds to take root among the grass and start an invasion. To water your sod:
- Water new sod twice daily for the first 2 weeks after sod installation.
- For an in-depth sod watering schedule, check out our tips for successfully getting sod to take root.
- Gradually reduce watering as your sod begins to take root, until you are watering twice weekly.
- If your sod is looking dry, discolored, or shrunken, provide water so your grass can thrive.
Sod requires frequent water until it has developed deep roots that can pull moisture from the soil. For the first few weeks, sod gathers all its moisture from the thin layer of soil that comes with the sod. The sod pieces should be kept consistently moist (but not soggy) until the sod has begun to take root. You’ll know your sod is growing roots and becoming strong enough to choke out weeds when it is green and the sod pieces feel “tacked down” to the soil when you try to lift them.
How Do You Get Rid of Weeds Growing on New Sod?
In order to stop weeds that are growing in your new sod, follow these steps:
- Identify the weeds to determine if they are grassy weeds or broadleaf weeds.
- Hand pull weeds if possible, to reduce sod damage that can be caused by spraying herbicides.
- If you choose to spray a weed killer on your lawn, make sure it is a selective post-emergent herbicide that is safe for your grass and engineered to kill the weeds in your yard.
- Water your sod frequently to develop thick grass growth that prevents new weeds from sprouting.
Weed issues can ruin the look of your new sod lawn. However, it’s essential to use gentle tactics to kill weeds without damaging fragile, young sod. With water, care, and light anti-weed measures, you can cultivate a green lawn without a weed in sight.