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Overseeded in fall: How long to wait until weed killer?

8K views 10 replies 7 participants last post by  PeterRegent 
#1 ·
Even though we have had the snowiest winter in many years here in South Dakota, spring is not far off my mind and mowing the lawn (not shoveling snow!). So my question is can I use weed killer on my yard early this spring? I overseeded late fall, about 3-4 weeks before the snow finally came. I know I have heard that weed and feed is a joke...can someone elaborate on that?

I just want a nice, green lawn this year and not be patchy with weeds and some dead spots that take an act of nature to grow.

Thanks
 
#2 ·
Scotts has a good weed and feed, I use it and it has always worked well for me. The important thing is too make sure you get a weeder that if specific for the weeds you get. Some are not to be used on specific types of grass. I believe you really don't use a weed killer until weeds start to show. You can combine it with a preventer to get them before they start. Remember to de-thatch your lawn especially if has been awhile. It will help clean out the dead grass and get out any moss or bugs that has invaded your lawn. Some of the dead spots if not due to weeds could be pests on your lawn. You might think about putting down a pesticide. As far as when to apply I am no expert about your region but I would do it as soon as the threat of freeze is over.
 
#4 ·
Can you tell if the seed took? Hopefully the snow cover actually provided a little bit of relief to let the seeds germinate and roots develop.

What you do not want to put on, just in case the seeds didn't pop open yet, is anything with pre-emergent herbicides. If it were me, I would feed it again in the spring and not apply an herbicide yet. Mow it tall. Give it a chance. If you set your mower a bit higher the grass, well nourished, will kill off a lot of weeds. Strength in numbers.

Not sure what grass seed you tossed down by the way? Not an annual rye grass I hope?

That said, if the herbicide is just for broadleaf weeds, you should be alright.

I really, really have nothing against Scott's but that the company gets $18-25 bucks for W&F that also comes in generic plastic bags for $10 but without pretty pictures of lawns on them.

And if your situation is broadleaf like dandos and so forth? Ortho weed be gone, if still allowed where you are, applied with a mask and hose end thing works as well as anything for a small residential lawn.

Things like creeping charlie are a whole different ball game. All the W&F on the planet will not kill it. Boron will but is illegal to use in many states. It is a natural mineral but can render soil sterile if not used properly.

Used to manage high end turfgrass for part of a living.
 
#7 ·
So my question is can I use weed killer on my yard early this spring?
I would not. Give a light spring feeding first and wait a few weeks. This will:
A. Give an accurate picture of how bad weeks vs lawn is.
B. Get the weeds actively growing as well, which will help the herbicide process. See the label, "Apply when weeds are actively growing."

I overseeded late fall, about 3-4 weeks before the snow finally came.
Which was when exactly?

I know I have heard that weed and feed is a joke...can someone elaborate on that?
I never use granular post-emergent herbicides. The reason is- Read the label. It says to apply to wet foliage but do not water in. The foliage must be wet for the granular to stick. And it must stick to it for a length of time to be absorbed. Same for putting granular fertilizer on wet foliage. You will burn the foliage. Also, if you read brand X dry fertilizer it says to apply to dry foliage and water it in with a certain amount of irrigation, say one inch. The herbicide will say the opposite as above. So if you use a combination product you have to be wrong with one of them.
That said, the liquid concentrates (hose-end) are not as much a problem as far as watering is concerned. However, my practice is weed if you need to weed, feed if you need to feed. The one shot does all does not allow you to tailor the amount of each product for your particular site. Therefore, you may be applying too much or too little herbicide and the same with fertilizer.
 
#9 ·
Since you overseeded in October, I would wait until after spring greenup before applying any herbicide. Since this is a new lawn, I'm still thinking a light fertilization and let that do its work a few weeks before weed control. Think in terms of giving a child an adult dose of medicine.

All of the brands are generally competitive. Some of the commercial formulas may be little different and a better cost per ounce but you're buying by the multi-gallon instead of by the pint/quart.

I presume that you are in preventive mode at this point. Unless you have a significant problem with a particular weed, you probably need to go towards the pre-emergent products. In contrast to post-emergent products, these will generally need to be watered in and the concern with the W&F granulars does not apply here. These also will be less dangerous to your new lawn as they work in the top inch or so of soil and affect the new roots. Once your lawn is well established, there should be no problem.
 
#11 ·
I would give the lawn a chance to get growing before putting anything down. My gut feeling is that some weedkillers will actually be more effective if used in the growing season.

With young children in the house I try to avoid putting anything on the lawns where they play, so its a case of hand weeding - which isnt too bad on a nice day and doesnt actually take that long to complete.

When I have used weedkillers I've found them to be very effective, much better than ones I'ved used in the past. Of course getting the application rate right is critical. Last year a neighbour completely ruined their lawn by getting the dose wrong - it still hasnt recovered, I think they will have to dig it up and relay it all.
 
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