Will Weed and Feed Kill Grass Seed? When to Plant and Spray Many gardeners often find themselves unsure of how long they’re supposed to wait until they can apply weed and feed to their lawns Garden Guides is the ultimate resource for cultivating your green thumb. Learn how long it takes Scotts Weed and Feed to work to make sure you apply the right amount at the right times.
Will Weed and Feed Kill Grass Seed? When to Plant and Spray
Many gardeners often find themselves unsure of how long they’re supposed to wait until they can apply weed and feed to their lawns after planting grass seed. Conversely, the issue may be how long one’s supposed to wait to plant grass seed after spraying weed and feed. For both concerns, the answer largely revolves around the type of herbicides found in different weed and feed products.
Can you put weed and feed on grass seed?
You may be having an irresistible urge to spray weed and feed on your recently overseeded turf after spotting one or two weeds sprouting on the lawn. However, the growing seedlings will not be able to survive the strength of the herbicide. If you’re planning to use a weed and feed product with a post-emergent herbicide on your growing turf, wait until the grass roots anchor deeper into the soil and the lawn is established.
Also, some weed and feed products are non-selective, pre-emergent herbicides targeted at preventing weed seeds from sprouting. As such, when they’re applied on a recently seeded lawn even before the grass seeds germinate, they’ll kill the weed seeds as well as the grass seeds.
To control weeds on lawns before the new grass is established, consider alternative measures like spot treatments. You can also manually uproot the weed plants if the infestation is still in the early stages.
Mowing also helps to control weed growth in newly-established lawns, as the grass grows stronger and crowds out more weeds. In fact, it’s advisable to refrain from spraying weed and feed on your new turf until after the third mowing. By then, the grass will be strong enough to withstand herbicides.
However, even then, you should only use a post-emergent, selective weed and feed product. These will easily kill broadleaf weeds like dandelions and clover without harming your turfgrass. Pre-emergent herbicides won’t work on already existing weed plants, while non-selective/systemic herbicides will kill both the weeds and your growing turfgrass.
When to plant grass seed after weed and feed?
The best time to plant grass seed after applying weed and feed depends on whether the weed and feed used contained a pre-emergent or post-emergent herbicide. For weed and feed products containing post-emergent, systemic weed killers, you can plant grass seed as soon as two weeks after application.
That’s because systemic herbicides don’t leave any residue in the soil that might harm seeds grown a few days after. They’re instead absorbed into plants via the leaves and roots, killing the whole plant within 7 days. Common examples of systemic herbicides include glyphosate and pelargonic acid.
Pre-emergent herbicides, on the other hand, are formulated to inhibit seed germination by forming a chemical barricade atop the soil. Thus, if you plant your grass seed soon after applying a weed and feed with a pre-emergent herbicide, they won’t sprout as the herbicide will still be in the soil.
To seed your lawn after using a pre-emergent weed and feed, you may have to wait between 1-6 months, with 2 months being the average wait time. This is due to the wide variation in the duration it takes for different types of pre-emergent herbicides to degrade in the soil. A herbicide like 2,4-D decays in as soon as four weeks, but you may have to wait for six months to plant grass seed on a lawn treated with Atrazine herbicide.
Take note, though, that there are some types of weed and feed products that can be used to suppress weed seeds without affecting grass seed. These products usually contain siduron, a pre-emergent herbicide that also boosts germination of grass seed. If your pre-emergent weed and feed contains siduron as the primary active ingredient, you can sow grass seed right after application.
Note: Always read the labelling on your weed and feed for information on how long you should wait to plant grass seed post-application. The types of herbicides infused into the product usually determines the manufacturers’ wait time recommendations.
How long after seeding can you spray for weeds?
It’s not uncommon to find weeds sprouting and growing on your lawn alongside your new grass seedlings. The right time to spray selective weed and feed on your lawn after seeding is after mowing three times. At this stage, the grass is mature enough to withstand the harsh chemical herbicides inside the weed and feed.
You can also spray a pre-emergent weed killer if the weed infestation is still in the earlier stages. When you start to notice weeds on your new turf, it’s a sign that more weed seeds are present in the ground and are about to germinate.
You should spray a pre-emergent at least 14 days after seeding, after the grass seeds have germinated into seedlings. As such, you’ll be targeting only the weed seeds that haven’t yet sprouted, and not your grass seeds.
Note: Never use a non-selective weed killer on your new lawn, no matter how mature the grass looks, as it will kill all plants it comes into contact with including the grass.
Weed Control Tips after Seeding a Lawn
You can keep weeds out of your lawn after seeding by adopting the proper watering, fertilizing, and mowing practices. Doing so helps your turf grow stronger and stay healthy enough to choke out weeds.
How Many Days Do You Have to Wait Before Seeding After Weed & Feed?
You want a beautiful lawn for your family to enjoy, but it’s no longer enough to just mow it. You have to fertilize, water, kill weeds and then reseed any bare spots. Using a weed and feed product saved you some time, so now you’re ready to plant some grass seed. You may have to wait a bit longer, though, depending on the type of weed and feed product you used.
Weed and Feed
Weed and feed products consist of fertilizers such as nitrogen or potassium, and a pre-emergent or post-emergent herbicide. If the weed and feed is designed for spring application, it contains a pre-emergent. If it is designed for later in the growing season, it incorporates a post-emergent herbicide. Knowing which one you are using is important because the herbicides affect plants in significantly different ways.
- You want a beautiful lawn for your family to enjoy, but it’s no longer enough to just mow it.
- Using a weed and feed product saved you some time, so now you’re ready to plant some grass seed.
How They Work
Pre-emergent weed and feed is applied in early spring so the herbicide is in place before the undesirable weeds germinate. Pre-emergent herbicide works by inhibiting germination. It must be watered with at least one-half inch of water to move the chemical from the surface into the soil. Post-emergent herbicides, however, must be applied while the weeds are actively growing because for the chemical to work, the herbicide must be absorbed into the plant.
Why You Wait
Since weed and feed products are designed to prevent germination — or to eradicate a living plant — they can, for the most part, have a similar effect on young turf grass. The only exception is the pre-emergent herbicide siduron, which is actually used to assist in seed germination. When using a pre-emergent that does not contain siduron, wait a minimum of two months before seeding. If using a product designed for broadleaf weeds, read the label carefully, because the active ingredient in these post-emergent herbicides have a wider range for the waiting period. Grass can be planted in as little as one month after application for products using 2,4-D to as much as six months for atrazine-based products.
- Pre-emergent weed and feed is applied in early spring so the herbicide is in place before the undesirable weeds germinate.
- Post-emergent herbicides, however, must be applied while the weeds are actively growing because for the chemical to work, the herbicide must be absorbed into the plant.
Proper Seeding Methods
When you are ready to seed your lawn, use a garden rake to remove debris and to break up the surface to ensure the seed comes into contact with the soil. Broadcast the seeds in two directions to ensure complete coverage, and water the ground lightly and often for up to two weeks — keeping the soil moist. Once seedlings have established, gradually reduce the frequency of the watering, but lengthen the amount of time per watering. This will encourage a deep root system for your grass.
How Long Does Scotts Weed and Feed Take to Work?
It may take up to 14 days to see full weed-killing results from Scotts Weed and Feed. However, the effects of the fertilizer component in the weed and feed will begin to work in as little as 1–5 days, with additional results for several weeks afterward.
The active ingredients in Scotts Turf Builder Weed and Feed are Dicamba and Mecropop, which are both post-emergent herbicides that attack established weeds in your lawn without harming the grass. These herbicides work by attacking plant systems to kill weeds down to the root. This process takes time but yields great results.
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How to Apply Scotts Weed and Feed for Best Results
To get the most out of your weed and feed, it’s essential to apply the product to your lawn at the right time and under the right conditions. Scotts Turf Builder Weed and Feed performs best when applied according to these guidelines:
- Temperatures are 60–90℉.
- The lawn is damp (from dew or light sprinkling) but not wet.
- A lawn spreader is used to evenly distribute the product.
- Do not water the lawn for 24 hours after application.
- Avoid mowing for 48 hours after application.
A damp lawn provides the best surface for the herbicide to stick to weed leaves, which helps the weed control product infiltrate the plants and begin killing them. This provides a huge boost in its effectiveness. Just make sure your lawn isn’t so wet that the product washes away.
Signs Scotts Weed and Feed is Working
How will you know if your lawn care mission was a success? In order to determine if your Scott’s Weed and Feed application is delivering results, look for these signs:
- 1–5 Days: Greener grass that appears to be growing thicker and faster.
- 7 Days: Initial yellowing and wilting of weeds in the grass.
- 14 Days: Most weeds in the lawn are brown, dead, and easily pulled out by hand.
- 30 Days: Most broadleaf weeds in the lawn are dead. The grass is much more green and lush than before.
By following the application for Scotts Weed and Feed, you will initially see your grass growth surge as broadleaf weeds begin to wilt. Over time, the weeds will die as the grass grows thicker, taking over places where weeds previously grew.
How Long Does Scotts Weed and Feed Take to Absorb?
It can take up to 24 hours for Scotts Weed and Feed to be completely absorbed into weed systems. This is the reason it’s important to avoid watering and/or mowing shortly after applying weed and feed.
Although most of the herbicides in Scotts Turf Builder Weed and Feed are absorbed within 24 hours, the chemicals still require time to work their way through the plant and kill it. Just because the herbicide has been absorbed doesn’t mean it’s done working. Remain patient as the product works to wipe out weeds.
Can You Water after Spreading Weed and Feed?
Wait 24-48 hours before watering your lawn after spreading Scotts Weed and Feed. If you water too soon after application, you risk washing the herbicide off plant leaves. Watering too soon after application can seriously diminish the effectiveness of the product.
- Avoid watering for 24 hours after spreading weed and feed.
- Do not spread weed and feed if rain is forecasted to fall within 24 hours.
- Water the day before spreading weed and feed, to ensure the lawn is damp but not wet.
Rain can wash away your weed control product just like a lawn sprinkler. If rain is likely to fall within 24 hours of applying weed and feed to your yard, wait to apply another day. If you’re worried about your lawn drying out, water the day before spreading weed and feed. This will keep the lawn moist, causing the weed and feed to stick to plant leaves and maintain grass health.
How Soon Can You Mow after Spreading Weed and Feed?
Allow 48 hours to pass after weed and feed application before mowing a lawn. Mowing can not only unevenly distribute fertilizer and herbicide, it can even throw weed and feed into garden areas, where the herbicide ingredients can harm vegetables and flowering plants.
- Wait 48 hours before mowing.
- Mowing too soon can spread weed and feed onto garden plants, potentially killing them.
- Fertilizer may be spread unevenly by mowing.
The fertilizer in Scotts Turf Builder Weed and Feed performs best when allowed a full 48 hours to break down and enter the soil. For best results in killing weeds and building a healthier lawn, hold off on mowing after application.
How Soon Will Scotts Weed and Feed Show Results?
Scotts Turf Builder Weed and Feed does two things at once: feeds your yard and kills weeds. You will begin to see a greener, healthier grass in 1–5 days, with full results in 4–6 weeks. On the weed control front, Scotts will begin to kill weeds within 7 days but will show complete results in 14 days.
When applied correctly, weed and feed will deliver a big impact by both killing weeds and boosting your lawn’s performance. All it requires is patience and correct application to get the most out of the product.