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Tbone1128
Need Lawn Help

I attempted to put in a new lawn in late May/early June. I got a good amount of germination from the new grass seed, but I also got a ton of crab grass. I want to be able to reseed in September but I do not know what my next step should be. Should I leave the crab grass alone and hope the new grass doesnt get choked out or should I attemp to treat the entire area with a chemical and hope only the crabgrass dies.

Any suggestions would be great.

keith3267
Re: Need Lawn Help

Just try a crab grass preventer in the spring.

HoustonRemodeler
Re: Need Lawn Help

Optimally you can spray for the crabgrass only then inject new seed directly into the soil.

OR

You can overseed with grass seed in the fall and wait until the cold weather kills the crabgrass The use a crab grass pre-emergent in the spring

ordjen
Re: Need Lawn Help

Houston,

Doesn't pre-emergent crabgrass killer also prevent the germination of all seeds, much like Preen?

HoustonRemodeler
Re: Need Lawn Help

yes, depending on the type used. Some work on only monocots, some work on only dicots.

keith3267
Re: Need Lawn Help
ordjen wrote:

Houston,

Doesn't pre-emergent crabgrass killer also prevent the germination of all seeds, much like Preen?

That's why it works so well. The OP could not have used a pre-emergent when he planted his lawn last spring because then the lawn wouldn't have germinated. Most lawn grasses are perennial so they won't have any problems coming back in the spring with a pre-emergent, but the crab grass, it's an annual so the pre-emergent will stop it.

ordjen
Re: Need Lawn Help

So, I should over seed in the fall early enough so that it germinates before spring?

HoustonRemodeler
Re: Need Lawn Help

Correct. Bluegrasses take about 3 weeks to germinate and get established. Rye grasses are much faster.

t_manero
Re: Need Lawn Help
ordjen wrote:

So, I should over seed in the fall early enough so that it germinates before spring?

Piggyback on the question:

(1) No. Virginia -- I think the soil is very high PH and we have NO sprinklers.
We have about 15,000 sqft of grass growing surface (I don't say "lawn" because our property is on a downward slope. In the front, we have several mini-lawns with probably different issues.

(a) One mini-lawn is a pie-shaped space fully shaded by an old Cherry Tree in the center. I'm told the shade & Cherry tree sucks up too much energy leaving the grass very blotchy & grasping for life. I want to try to revive it by overseeding and better watering.

(b) Another mini-lawn was sodded 2 yeras ago, but there are "bare areas"; no roots, no brown grass, just nothing. I want to try sodding the bare areas after laying lime to reduce the PH.

(c) Generally, we didn't care the grass at all besides spraying by TruGreen at the front (when we had just 2,500 sqft in Calif, I did the Scotts crab/weed & feed granules & had very good results). In No VA, it is like Cambodia with some species of weeds growing 3 feet tall in a month.
The result is varous grass areas have crab/weed & blotchy from the eratic water supply (rain only, no sprinklers).
Should I do a massive overseeding in early fall, and a pre-emergent next spring ?

PS - how fresh are seed bags from last year ?? They're the Scott's bags from HD.

(d) We also have planting areas mixed with mini-lawns both in the front & back. The planting areas are full of several weeds & invasive species that grow vertically (3 feet) and horizonally (like vines & maybe ivy). I am slowly pulling them out, one mini-area at a time, but they are fully established.
Would using Preen help to keep new growth in control ??
I suppose some old roots have survived and will grow out again . . . I don't want to use Roundup for fear of contaminating the good plants. Any ideas to last the summer, and also to keep things in control until next spring ??

We DIDN'T mulch this year because of expense (layers of mulch were piling up and we didn't want to throw $3,000 at the weed probem year after year). The downward slope, amount of area and our old ages have deterred us from tackling the problem head on (also No Virginia weather is not as bad as Texas, but it's winter, then a cold spring and summer weather beginning June 1 keeping us indoors & free from heart attacks).

ed21
Re: Need Lawn Help

I would treat the weeds as much as possible before the fall. Check label on when to stop for reseeding. crabgrass killers don't work too well from my experience. better to put a pre-emergent with Dimension in it in the spring.
Rake or thatch out the crabgrass out as much as possible, then reseed. Covering the seed or using a slit seeder will get better results with germination. In northen MD where I am, I have reseeded as late as end of september/early october with okay results. It depends on the weather. Mid september would be better. VA is a few weeks at least behind in cold weather.
Fetilize when planting. Hope for some fall rain. At least the temps are down.
Use preemmergent in the spring to keep the crabgrass at bay.

keith3267
Re: Need Lawn Help

ordjen, many grasses produce seed heads in the fall. You can just hold off mowing until you see seeds falling from the good grasses, then mow high (thick) to protect them and let them germinate. You can also add seed to overseed if you like, but watch what your grass is doing, it will help you select the best time to overseed.

t_manero, if you suspect that you have a high pH, do not lime. Limestone raises the pH, use gypsum instead. Before you do anything, you should get a soil test first to be sure. If it turns out that you have a high acid soil (low pH), then use limestone, but use straight limestone and apply in the fall and till in.

Another way to combine mulch and decrease a high pH soil is to gather shredded leaves and pine needles this fall. Shredded Oak leaves are the best. If you can find some people around town that have Oak trees and who shred and bag these leaves in the fall, gather up as many bags as you can. Spread up to a two inch layer in the bad spots and till it in, then seed with an annual Rye grass.

In the spring, mow high once, then go over low, preferably with a mulching mower. Do not till the Rye grass. Overseed the Rye with the desired grass and after it germinates, then fertilize with a high nitrogen fertilizer, straight Ammonium Nitrate or Urea Nitrate would be best if you can get it, but don't overdo it.

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