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Northeastern lawn help, seed / crabgrass preventer + aerate / thatch

Mark D
7 years ago

Evening all... Live in NJ and bought our house last year. Last summer, I really didn't do much with our lawn because of other concerns. Now I want to get it going. I did thatch last fall and alot came up. I do notice I still have some dead grass/thatch and some dead "weeds" crabgrass. Also last year the entire lawn almost became crabgrass. Now, the majority of the lawn is thinning, there are no big bald spots.
Few questions / areas I'm looking for advice:
1) I want to seed and also put something down to prevent crabgrass, but a few of the brands (Scotts et al) all say don't use the crabgrass preventer if putting down seed. Any thoughts?
2) Should I rent aerator from HD, aerate then thatch again before putting anything down?
3) any other general advice?
THANK YOU!

Comments (3)

  • dchall_san_antonio
    7 years ago
    1. Heed the wisdom. It is sort of ironic that Scott's wants to sell you more product but they put that warning on one of them. Seed should be put down in the fall. You missed your chance last year. I realize they sell seed now, but now is a bad time to put it down. Tomorrow is worse and it gets worse and worse until fall. Now is a great time to prevent crabgrass, though. There is a lot more to the conflict between spring seeding and weed control, but the best thing you can do at this point is take good care of what you have. That alone should minimize the weeds.

    2) No. You don't need to dethatch. Dead grass below the live grass is normal. There is also the possibility that you have Kentucky bluegrass which is still dormant. So it might look dead but it will come back. Let's all cross our fingers for that. That would mean you don't need more seed, because KBG spreads to fill thin spots without reseeding. Fescue and rye grass do not do that.

    3a) Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the daytime air temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall.

    3b) Mulch mow at your mower's highest setting.

    3c) Fertilize on Memorial Day, Labor Day, and Thanksgivingish. Once a year I would use an organic fertilizer in addition to, or instead of, the first two applications. I went completely organic after trying it once, so you might have the same experience.

    3d) Spot spray weeds in mid April. Use something like Weed-b-Gon or Weed-b-Gon Chickweed, Clover, and Oxalis Killer. Don't use a granulated herbicide as it is a waste of herbicide and a soil contaminant.

    3e) Don't use an insecticide unless you have insect damage on your lawn. Just because your neighbors use a preventive insecticide every June, don't fall for that.

    3f) Get ready to reseed if you need to in August. Then do the reseeding in September (in NJ). That gives the grass time to come in and for you to evaluate whether you need more seed.

    3g) The last fertilizer application of the year is a winterizer. It should be a high N, fast release product. Wait until the grass has stopped growing but before it goes totally dormant. The idea is to push nutrients to the roots without stimulating new growth, so the grass has to have stopped growing for the year. Then next spring your lawn should be one of the first to awaken.

    3h) If you have hard soil when it is moist spray with shampoo at a rate of 3 ounces per 1,000 square feet. Any clear shampoo will work. Follow that with 1/2 to 1 inch of water to get it down into the soil. After 3 weeks you should see the soil getting softer after it rains or when you water.

    3i) Don't get tempted to topdress with soil or sand. That will change your drainage in ways you don't want.

    3j) Proper watering (3a, above) is the single most important thing on this list. If you don't get that right you will run in circles with this product or that and with aeration and dethatching when you don't need it.

  • Mark D
    Original Author
    7 years ago

    @dchall_san_antonio THANK YOU, great info and very informative.

    So if I understood correctly, you would basically recommend skipping any type of seeding/aerating/thatching now, put down the fertilizer/crabgrass preventer and take care of what I have.

    * You wouldn't recommend a Scott's product safe for new seeding: Scotts® Turf Builder® Starter® Food For New Grass Plus Weed
    Preventer? This was recommended at a local store.

    * Regarding the mowing question - which I also was wondering, I have a mulch/mower and last year I think I set it too low and it caused too much of the thatch on lawn. You would raise it up to highest setting and set to mulch? Basically not bagging anything?

    Thanks for the watering tips, I assume based on what you said, frequent watering is when seeding, but other times deep and infrequent, correct?


    THANKS for input, very helpful!

  • dchall_san_antonio
    7 years ago

    You did understand correctly about skipping all the hard stuff but do NOT put down fertilizer until late May. Jumping the gun on spring fertilizer is a rookie mistake. Some people get into that habit, but it is a mistake. If you wanted the grass to look good early in the spring, then late fall was the time to fertilize. And then use a starter fert for the new grass. You can use crabgrass preventer.

    Correct about the mowing and water. Thatch is a rare event. It can be caused by very shallow daily watering combined with fertilizing twice a month with a liquid fertilizer. If you are not doing both of those things then you likely just have dead grass that is not decomposing quickly. Grass decomposes quickly when the soil biology is up to speed. There are a hundred thousand species of microbes living in the soil that need to be fed. The clipped grass is a great food for them, but sometimes they need a tonic. You could kick it up their population and metabolism by spraying the yard with 3 ounces of molasses per 1,000 square feet. One or two doses of organic fertilizer will help, also.