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llo0dqle

Questions on mowing and weed killing after overseeding

llo0dqle
10 years ago

Hello,

I am a first time home owner and I just moved in end of May. The previous owners had a dog so the back lawn (which is pretty small - it's a half duplex) was full of dog spots - about 50%. It was also full of dandelions. It has a detached garage in the back and on the one side of the garage, the grass was pretty much dead and full of yellow straw like hay. The front lawn wasn't bad, but was a bit thin and had a few dog spots as well. So, I decided to overseed.

I didn't really know anything about lawns or grass before all this but I did quite a bit of reading and have learned quite a bit. I don't know what the existing grass was but if I had to guess, it's probably fine fescue. I mowed the grass as short as I could with my Yardworks 14 inch reel mower. I dethatched for hours with a dethatching rake. I pulled dandelions (as many as I could). I core aerated with a manual aerator I got from Home Depot. I put lime on the dog spots. I top dressed with Scotts enriched lawn soil (about 12 bags of it overall) covering about 1/4 inch of the topsoil. I spread Scotts Premium Sun and Shade mix with the Scotts hand spreader and finished off with Scotts starter fertilizer. I then ran my leaf rake upside down over the lawn to press the seeds into the soil. Finally, I watered the lawn.

I did all this about a week ago and have been faithfully watering twice daily to keep the soil moist. Now, the existing grass is pretty long (about 4-6 inches) and I think the seed is just starting to germinate. It's hard to tell because of the existing grass but the mix is PRG, Red Fescue (I think) and KBG. I think it's the PRG that's starting to sprout. Also, the dandelions are starting to grow tall and my front lawn is starting to have quite the population (I think partly due to my neighbor who neglects her lawn and has a million dandelions growing).

So, my first question is, when do I mow? I've googled and googled and googled and I'm getting different views. Some say wait as long as possible so as not to disturb the seedlings. Certain pro articles say keep mowing and keep it at 1.5 - 2 inches so the seedling are not in the shade of the tall existing grass. Some say, mow when the height of new grass is 2-3 inches. Now, if PRG germinates at 7-10 days, red fescue at 14-21 and KBG at 21-28...when the heck do I mow?? My other concern is that the existing grass is getting long and it might be depriving the seedlings of sunshine. But if I mow using my reel mower, I will be leaving long clippings which can smother the seedlings. If I rake them, I might be uprooting seedlings. If I borrow my dad's gas mower so I can bag the clippings - other articles/forum discussions say that it will suck up the seedlings. I'm so confused.

Also, regarding the dandelions..(I think all the weeds are dandelions, I don't think I saw crabgrass and I don't know what quack grass is or other weeds). Can I spot spray with Killex right now? Or do I have to wait until the new grass is established. Better yet, can I broadcast spray the Killex? If so, when can I do this? Killex supposedly doesn't affect the lawn but the label doesn't specify regarding new seedlings. Some articles vaguely say to wait 8-10 mowings before doing any weed control but I don't know if that applies to Killex per se.

It's day 8 since I overseeded and I am constantly thinking whether I should mow the lawn now or wait. If I wait, I'm wondering when I should do it.

Please help and thanks in advance.

Comments (2)

  • dchall_san_antonio
    10 years ago
    last modified: 9 years ago

    My psychic senses are telling me you have a tendency to over think everything in your life.

    Normally I would say you seeded too late and the summer heat is going to burn up your new seed, so why get excited about this or that issue with it. But you are just now coming into spring...and fall is just around the corner.

    When do you mow? When the old grass is 5 inches high, mow it down to 4 inches. Don't worry about the new stuff. You still have time to fix it if there isn't enough germination. You should be able to walk on newly seeded soil because you should have used a roller to roll it down. Too late to do that now if you missed your chance, but walking on the new seed actually improves the germination. Why? You get better contact between the seed and soil. I understand that you don't want to break off the newly germinated plants. Walk carefully.

    We've never talked about this before but when someone wants a mix of grasses, they should order the seed in separate bags. Apply the KBG at day 1, apply the fescue at day 8, and apply the rye at day 15. That way all the grass should come up at the same time. There must be a problem with that that I'm not thinking of.

    I would wait to deal with the dandelions. Spot spraying is far better than broadcast anything. The weeds will take care of themselves once the grass is in and becoming dense. Next year should be a totally different story. And it doesn't matter that your neighbor has a weedy lawn. It is your lawn that matters. It needs to be dense and mowed up at least 3 inches high and I like to go to 4 for your mix. Tiemco will come here and make a good argument for 3 inches, so I am including 3 in my suggestions. Just don't mow it short again.

  • llo0dqle
    Original Author
    10 years ago
    last modified: 9 years ago

    Thanks for your reply. However, your psychic senses are wrong. I do tend to analyze things, especially when it's regarding a new endeavor/field I have no prior knowledge/experience of. It has yielded outstanding results for me in the past and so I continue to approach things in this manner.

    Regarding seeding too late - well, first off, I just took possession of the house so I couldn't seed earlier. Also, I live in Edmonton, Alberta Canada and if you've ever lived here, you would know that our summer is pretty much about 2 weeks long. lol Anyway, When I did the overseeding, it was about beginning of June and temperatures were about 10 C - 20 C and we've been getting a lot of rain lately. In fact, we're just starting to go up to highs of 20 C - 25 C and in about 5 days is the first day we're supposed to hit 29 C, as per the forecast. I know that Spring and Fall are the textbook times to overseed but our weather/termperatures here does not conform to the norm. Our temperatures in October are already winter temperatures for a lot of places in the States. Also, I did not want to wait until fall because I wanted to get started on thickening the lawn asap.

    I was confused with this statement though: "But you are just now coming into spring...and fall is just around the corner." Spring is technically done..did you mean, "just coming into summer"?

    I usually mow at around 4 -5 inches and only take a bit off. I know all about the "only take 1/3 off" and "mow high" recommendations. I only scalped it this one time to prepare for overseeding to facilitate better seed to soil contact. I've read about the roller thing but decided that it wasn't needed. I did not want to compact things any more either especially since I was core aerating. I ran my rake through the soil and seeds to enhance seed to soil contact and this is a technique that has been recommended in several articles and videos. I also did not want to bury the seeds too deep. In fact, I already have baby grass growing to about heights of 2 inches now. I only noticed them yesterday and they are even much taller today.

    I like your idea of sowing KBG first, then fescue then PRG but here's the thing - I have not found any stand alone seed packages in my local Walmart/Home Depot/Canadian Tire stores. They are all blends. I haven't gone to garden centers though but that's also because I do not want to pay more for something that sells less at Home Depot. Also, I think this says something.. I think that for our climate and grass types, the seed blends probably tend to work better. I think this is evidenced by the fact that I primarily see Scotts Sun and Shade being sold in all these places and not the other types - i.e. high traffic, high heat etc.. Also, this blend tends to get the best reviews on Canadian Tire.com.

    The other thing too is that I've read blends were made so that the PRG can germinate first and help establish the turf while the fescue and KBG are taking their sweet time to germinate - helps with thickening up lawn quicker and crowding out weeds. If I wanted to wait (or had the luxury to do so - i.e. lawn isn't too bare) the full 21-28 days, then I would probably just seed with pure KBG and not worry about blends.

    I've decided to wait with the dandelions. I've emailed Scotts and they said to wait after mowing the new grass 3 times before using Killex as it destroys grass seed and new grass. Just wondering why you say spot spraying is far better than broadcast anything. I just feel that if Killex is safe to use on an established lawn, it would be more efficient to just broadcast it, in terms of time and coverage.

    Regarding my neighbor's lawn - I'm not worried that her lawn looks like crap..I just feel that her dandelions are invading my lawn and I can see that most of the dandelions on my lawn are on the side close to hers. Anyway, I'm just gonna keep mowing high and hopefully it gets thick enough to crowd out weeds and hopefull I won't have too many dandelions and I'll just deal with them as they come.