# Aeration and overseeding timing



## CPA Nerd (May 8, 2018)

I am in the Chicago area. My lawn is being double pass aerated on Monday by a professional.

Ideally, I want to aerate and overseed on the same day. Is Monday 8/20 too early for overseeding? It should be in the low 80s for high temperatures in the next 10 days.

Let's say I'm good to go, but it's pouring rain on Monday when I planned on overseeding. If I aerate Monday, but wait a couple weeks to overseed, am I hurting my germination chances?

Some people say overseed immediately after aerating. Others say it doesn't matter. Some say now is the time for northern IL seeding. Others say wait until cooler weather.

I will have sprinklers and timers set up so my instinct is that weather a bit warm doesn't matter much.

Thoughts and opinions? Thank you in advance.


----------



## Ecukingbuddy (Jul 22, 2018)

I would say you want to overseed sooner than later. Seems like Chicago has its first frost risk in the Middle of October. Give you about 8 weeks if you do it soon before the chances get really high of that happening. I definitely wouldn't wait any longer than the end of August.


----------



## g-man (Jun 15, 2017)

I would make sure I follow successful renovators in your area. Pete1313 is in Rockford, IL and I think he drop seeds 08aug last year. I'm a few miles south and I want to drop this weekend, but it is a muddy mess out there with 3 days of rains.


----------



## Delmarva Keith (May 12, 2018)

Where I am, for fescue at least, anywhere from mid-August through mid-October has been successful. The earlier it goes down, the more difficult it is to keep continuously moist while avoiding fungus and the later the more difficult it is to make sure it's up and growing strong before it gets really cold. Pick your poison


----------



## CPA Nerd (May 8, 2018)

Thanks for the responses.

I would prefer to wait another couple weeks, but the aerating is being done Monday. Tough to change that because all of the companies are booked several weeks out.

I guess my options are:

A) Overseed on Monday after the aerating
B) Overseed in a couple weeks, but the cores will be broken up already.

If I do B, will I be able to get good seed to soil contact?


----------



## Pete1313 (May 3, 2017)

I would not seed on Monday. There will be a front coming thru Monday/Tuesday with the potential for 1"+ of rain. If I were in your shoes I would seed on Wednesday or the following weekend. It looks like after that front, the humidity will drop a bit with some slightly cooler night time temps. On a plus, with all the rain we have gotten and a dry weekend ahead, it should be a perfect time to aerate on Monday ahead of any storms.


----------



## CPA Nerd (May 8, 2018)

Pete1313 said:


> I would not seed on Monday. There will be a front coming thru Monday/Tuesday with the potential for 1"+ of rain. If I were in your shoes I would seed on Wednesday or the following weekend. It looks like after that front, the humidity will drop a bit with some slightly cooler night time temps. On a plus, with all the rain we have gotten and a dry weekend ahead, it should be a perfect time to aerate on Monday ahead of any storms.


Thanks, Pete. So you think it's fine to aerate on Monday 8/20 and then not overseed until the following weekend?

I will have to mow and collect the clippings again before seeding. Is that bad to do less than a week after aerating since I may end up picking up some of the cores?

Another option: Look at aerating and seeding as two separate things. Aerate on Monday 8/20, give temps a few weeks to cool off and the cores some time to decompose, and then overseed and roll in a couple weeks. Thoughts on that approach?


----------



## Pete1313 (May 3, 2017)

I think you will be fine either way, but I would put it down this weekend.


----------



## CPA Nerd (May 8, 2018)

Pete1313 said:


> I think you will be fine either way, but I would put it down this weekend.


Even if that means mowing short after aeration and picking up some cores?


----------



## g-man (Jun 15, 2017)

I think your goal is to grow grass from seeds before winter. They need to grow enough to survive the winter. The soonest you could drop the seeds the best. In our experience, you should have your seed in the soil this weekend after the forecasted rain. Could you go later? sure, but you run the risk of an early winter showing up. There is no way of knowing the future weather unless you have a flux capacitor.

My mower never picked up cores. Even if it did, so what? throw them away. If the stay behind, they will dissolve soon with rain and your rolling. The seed will be ok, nature has made the seeds to be very resilient.


----------



## CPA Nerd (May 8, 2018)

Aerating is happening this morning. Later today some big storms are coming through.

I'd like to seed this weekend, Friday-Saturday 8/24-8/25. However, here are the temperatures forecasted:

Friday 8/24 - 76
Saturday 8/25 - 86
Sunday 8/26 - 90
Monday 8/27 - 89
Tuesday 8/28 - 89
Wednesday 8/29 - 89
Thursday 8/30 - 85
Friday 8/31 - 84
Saturday 9/1 - 82
Sunday 9/2 - 82
Monday 9/3 - 83

Would it be more prudent to wait an additional week and do it 9/1-9/2, Labor Day weekend?

I do have the ability to water 4x a day if need be. I just don't have a ton of experience and am wondering how bad the 90 degree temperatures will be for new seed even with frequent watering.


----------



## jessehurlburt (Oct 18, 2017)

I seeded a few weeks back in CT with similar, high temps and it came up fine with frequent watering. What type of grass are you growing again?


----------



## CPA Nerd (May 8, 2018)

jessehurlburt said:


> I seeded a few weeks back in CT with similar, high temps and it came up fine with frequent watering. What type of grass are you growing again?


GCI brand TTTF.


----------



## jessehurlburt (Oct 18, 2017)

If you're on the fence, wait a week. The soil will be nice and warm still next week and you should get quick germination. If you were seeding KBG, I would say throw er down ASAP. You have time to wait until next week, IMO with TTTF. Either way should be fine though with proper watering. Good luck!


----------



## CPA Nerd (May 8, 2018)

jessehurlburt said:


> If you're on the fence, wait a week. The soil will be nice and warm still next week and you should get quick germination. If you were seeding KBG, I would say throw er down ASAP. You have time to wait until next week, IMO with TTTF. Either way should be fine though with proper watering. Good luck!


Thanks. That's kind of what I'm thinking, that it probably won't make much of a difference. We may get 90 degree days in early September also, so it's kind of a crap shoot. I'll see how the weather is this weekend and how the forecast looks at that time and play it by ear.


----------



## g-man (Jun 15, 2017)

A day at 90F is not that important. Im seeding on Wednesday or Thursday (depends on the rain).


----------

