# Starter fertilizer on or 2 weeks in



## Babameca (Jul 29, 2019)

Hi,
I have seen few opinions about right timing for fertilizer while doing full reno/overseeding.
I understand that many factors come in place and will stick to 2 weeks in for my overseeding area.
For my full reno, I have prepared a 10-25-10. My soil tests always showed low P. I am attributing this to 2 renos in 2 years. Young grass is 'hungry' for P.
I know also seed does not need much until germination. It has it all. KBG takes 4 weeks to kick in really (not talking about baby grass).
The dilemma to me is:
Do I still apply fert at seeding. Nitrogene is a fast one and not going to hang around for long. But I will supply P without the need to walk on the grass when it really hurts.
Or I wait for a first mow and hit then.
Well options 3 is the current rule to go 2 weeks in and smash some baby KBG under my heavy posture.
M


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## Sinclair (Jul 25, 2017)

I spread my starter fert same day as seeding.

I believe in staying off the new grass until it's time for the first mow, which was around day 33-35 for me if I remember correctly.


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## Babameca (Jul 29, 2019)

Sinclair said:


> I spread my starter fert same day as seeding.
> 
> I believe in staying off the new grass until it's time for the first mow, which was around day 33-35 for me if I remember correctly.


What rate did you use? what NPK?
Thanks!


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## Sinclair (Jul 25, 2017)

I just read my journal.

Push-reel mowed on day 26, rotary mowed on day 34.


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## Sinclair (Jul 25, 2017)

@gergelybg I used Scott's starter granular 24-25-4, at the bag rate, which I think gives somewhere between 0.5-0.75 lb N/1000 sqft.

I also sprayed a blanket app of Tenacity.


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## Babameca (Jul 29, 2019)

Sinclair said:


> @gergelybg I used Scott's starter granular 24-25-4, at the bag rate, which I think gives somewhere between 0.5-0.75 lb N/1000 sqft.
> 
> I also sprayed a blanket app of Tenacity.


I did same last year. Re applied at half rate 45 days in. I found to be a great recipe. I will try the new one now by keeping the P supply, which will drop N by more than 50%. In my head this may only help slowing the top growth down.
Will start the journal soon. At least all pictures are taken on time...
Thank you again,
M


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## troksd (Jul 27, 2018)

As much as 80% of what U put down went to waste. Grass seedlings are more resilient than U are giving credit. U are better off applying fert 1 month after seeding, than applying fert that will be lost to the atmosphere, leeching...



Sinclair said:


> I spread my starter fert same day as seeding.
> 
> I believe in staying off the new grass until it's time for the first mow, which was around day 33-35 for me if I remember correctly.


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## ericgautier (Apr 22, 2017)

On my last Reno, I did 5-5-0 the day before seeding. Then 46-0-0 10 days after germination then again a week later. Turned out ok.


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## Khy (Jul 27, 2018)

This isn't a one size fits all argument imo, soil type and type of grass seed you're dropping down plays a role here. If you have Sandy soil, you should ABSOLUTELY wait until your new seed has germinated and been cut once, because if you throw down fert at the time of seeding, those new seeds won't see a drop of anything in that fert. It will all just be watered through your soil before the seeds can even germinate. But if you happen to have clay soil, you might be okay.

Same concept, if you're planting KBG, you definitely should hold off as even in clay soil, 30 days for germination means you'll get a lot of N wash out from water and whatever isn't washed out will be used by your existing turf. Whereas if you're planting rye, you might even get away with fert/seed on the same day in sandy soils because of how fast rye kicks into action.

My personal view is I don't do nitrogen at overseeding. If you're low on P or K throw that down as that's not going to push a ton of top growth from your existing turf. My lawn is always insanely high in P on every soil test I've ever done and typically low on K, so usually coming out of summer and going into my overseed I'll throw down some 0-0-50 at the time of seeding and then similar to Eric, I'll start spoon feeding Urea after my first mow post-overseed.

The new seedlings don't need nitrogen that early on and most of the Nitrogen you're going to put out with your seed is just going to be watered out of the soil or used up by the existing turf grass by the time the seedlings can even gain access to it anyway. This is doubley true if you have a sandy soil type vs a clay soil.

A lot of times people try to have a 'one-size-fits-all' answer and lawn care really doesn't lend itself well to that. Your climate, grass type, soil type all play a role in the answer to 99% of the questions in lawn care. I think the better way to frame this answer would be:

It may be okay depending on your climate, grass and soil types to fert at the time of your overseed. But holding off on fert until after your first mow will basically never result in any issues, where as ferting at the time of seeding may result in low soil nutrition for your young seedlings and as such the "one-size-fits-all" answer here should be to hold off and if you know the answer to all the questions above about climate, grass and soil type you can adjust from there. But the newbie question answer would be "Wait until after your first mow" as you can't go wrong with that method.


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## Babameca (Jul 29, 2019)

Thanks for the different perspectives you brought to this post!
M


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## Suburban Jungle Life (Mar 1, 2018)

My vote for fert time is 1-2 weeks after germ. Fescue in my area at the end of summer germs in about 5-7 days. Rye 3 days. KBG is all over the place and might be 1 week or up to 3 weeks. I might not have mowed yet but all the seed has germinated and might be an inch to two inches. I'll pull one to check for roots but they always have some by then. I will hold watering for that day until after I fert so the surface will be a tad more firm. I also walk carefully and not drag my feet or stomp my feet as the ground is softer than usual from constant watering. I haven't seen adverse affects to the new grass from this process. All my foot steps grow grass just fine and none of it dies. If you have a steep hill and each step could tear out grass as your foot slides a little, then maybe not. Otherwise, I have no problem walking on new grass.


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