Overseeding question

Cool season grasses like Kentucky Bluegrass, Fescue & Rye
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Ti837
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Overseeding question

Post by Ti837 » Tue Sep 10, 2019 11:38 pm

I'm going to be over seeding my lawn this week and I had a few questions. My plan was to mechanically aerate, overseed with Falcon IV, put lime and scott's starter fertilizer down. I went to my local nuresery to pick up some lime and when I told them the plan, they told me not to put the Scott's fertilizer and put down some Milorganite instead so I don't burn the new grass. I was in the understanding that when overseeding, you need a high Phos and K but Milorganite doesn't have that. What do you guys think. Should I stick with scott's starter fertilizer or just the milorganite. Thanks

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Baretta
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Re: Overseeding question

Post by Baretta » Wed Sep 11, 2019 1:31 am

Neither. At least not starter for a few weeks. This overseed guide should help you.

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Ti837
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Re: Overseeding question

Post by Ti837 » Wed Sep 11, 2019 7:55 am

Thank you for the reply. I will hold off on the Milorganite for now. On the overseeding guide, it says to put a fertilizer with 0-25-25. What brand fertilizer has no nitrogen but high phos and potassium. Thanks

saidtheblueknight
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Re: Overseeding question

Post by saidtheblueknight » Wed Sep 11, 2019 8:03 am

Milo is a good option, but should be put down well before the seed due to its slow release nature. If you put it down at the same time, it won't really get going for a few weeks and even then it will be slow to come in.

I would still put a starter fert (even with N) but wait until 2 weeks or so after seeding. Don't go to heavy on it, and with watering you should have no real issue with burning. Burning comes from lack of water, which you shouldn't have with new seeding anyway. Lack of water will kill seed regardless if you have fert or not.

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Harts
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Re: Overseeding question

Post by Harts » Wed Sep 11, 2019 9:05 am

I see a lot of people are wanting to aerate before over seeding. Can I ask why you want to do so? Here are my thoughts:
  • Mechanical aeration is only really needed when the soil is overly compacted. If you can stick a screw driver into your soil 4-6" with relative ease, your soil is fine.
  • Yes, aeration can help open up a nice seed bed for you, but what about the cores? Are you going to break them up and drag them in? That's a lot of work. Are you going to shovel them off the lawn? That is also a lot of work. I don't believe aeration leads to significantly better success with an over seed project.
  • Mechanical aeration can also stir up dormant weed seeds in the soil. We know how we feel about weeds.
My advice for over seeding is to always scalp then use a power rake to bring up dead debris and some of the thatch layer then clean all of it up. This gets your existing grass nice and short and opens up the canopy for the new seed. It will also stunt the old grass, giving your new seedlings time to grow without competing for sunlight and nutrients.

As for fertilizer, I would skip it all together at seed down. Others have done it and have had success. I have always skipped the fert and had good success. So, there are different ways to get this done, but here is my rational: Your new seed has everything it needs for the first couple of weeks. Dropping nitrogen will stimulate the existing grass and force top growth. This forces the new seed to compete and it becomes survival of the fittest.

I would fertilize approx. 2 weeks AFTER germination and spoon feed it with fast release N. If you want to use the start fert at that point, go ahead.

With regards to lime, do you have a soil test that indicates your are deficient?

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ForsheeMS
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Re: Overseeding question

Post by ForsheeMS » Wed Sep 11, 2019 9:16 am

Around here you can pick up a 0-25-25 from feed & seed stores, the places farmers buy there stuff. A 50lbs bag of 0-25-25 runs me about $17 and a 50lbs bag of 34-0-0 fast release nitrogen runs about the same. Drop the 0-25-25 at 1lbs per 1k **IF** your soil test indicates you need P & K. If soil tests show your P & K are correct skip it. Our local farm supply carries fertilizer in several variations so I can create my own custom blend to suit what the soil needs. If you haven't done a soil test you are only guessing.

Save the nitrogen for after the first cut on the new grass. Adding nitrogen at time of seeding just creates more competition between the new grass and existing grass. New seedling do not need nitrogen for the first few weeks anyway.

I would also skip the lime until after the seedlings have established. Dropping lime at seeding can throw the pH way out of whack in the root zone (upper 1/2" of soil) for the seedlings. Wait until after the new grass is established and put the lime down according to the soil test recommendations. Again, without the soil test you're just guessing.

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Re: Overseeding question

Post by g-man » Wed Sep 11, 2019 8:42 pm

^+1 and the guessing could lead you to actually make things worst.

@saidtheblueknight fert burning/killing is caused by salts. The salt around the roots screw up the ability root ability to get water and nutrients. A lot of water can dilute and help flush.

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