Is the area where the grass is thin, in a shade? Not getting enough sunlight.

I would think so, but there are other areas with equal or more shade that the grass is doing very well.

What kind of grass do you have?

It was a sun/shade mix. I really wish I had saved the bags with the label on it. I'm sorry, I don't recall.

Regarding the weeds, are you able to identify the weeds. Broadleaf - dandelion, clover etc. or is it grassy weeds like poa annua. I had great success using 2, 4, D with triclophyr. I use a 14 gallon tow behind electric sprayer and sprayed the whole lawn. Also did you apply any pre-emergent in early spring?

Here are some photos of weeds. Yes, I applied pre-emergent through sprinklers in early spring. I did a half dose to make sure everything would be ok, and then did another half dose a few days later. That was I think in April when forsythias were blooming. I wish I had done the full dose all at once but I was nervous about doing it through the lawn sprinklers. Now that I know it was ok, I will do a full dose next year. I am looking for something that I can mix with the Urea that will dissolve in water, or something that is in liquid form already. I will do this probably tomorrow or this week some time and run through sprinklers again.

Is this what you use? What do you think about. this stuff?
http://www.amazon.com/gp/aw/d/B0072289CA/ref=mp_s_a_1_1?qid=1464633777&sr=8-1&pi=SY200_QL40&keywords=liquid+weed+killer

I have this exact issue with those same weeds. I was about to post the question as to whether tenacity or weed b gone (clover/chickweed) would be best..... And if I'm better off treating the whole yard or spot treating. Did you have new soil or did you Reno an existing lawn?

I redid the whole half acre. I brought in about 1200yds of fill and layed 2" of topsoil on top. Started from fresh seed.

Same here and I've got the same issue. Hopefully a pro chimes in because I don't want these weeds to get carried away

Any herbicide with 2,4D/mecoprop/dicamba should do the job. You can find it at Walmart or any other retailer with a lawn section.

tye22tye said: As for weeds, i see a lot of them in certain parts of the yard and I
was wondering what would be best as a weed killer to run through the
sprinklers with the Urea.

I'm the guy pestering you not to use your sprinkler system to distribute hazardous chemicals. If you don't agree with my logic last time, and you don't agree with the product label that tells you it is not acceptable to administer the product through such a system, maybe one of these people can convince you?

https://groups.google.com/forum/#!topic/rec.gardens/mZdV_Mavzac

I found this comment by brickeyee particularly to the point:

He said: If you get caught you will get nailed to the wall.
It is a violation
of every plumbing code to introduce anything hazardous into a system
that is not isolated by an air gap (and a they mean a real gap, not a
backflow presenter or vacuum breaker).

The plumbing code cannot
control all the hose end sprayers, or stop their use and manufacture,
but it applies to anything permanent.

No amount of back flow equipment is allowed for hazardous additions to the water.

from https://www.ar15.com/archive/topic.html?b=1&f=139&t=578455

Also be aware that products such as 2,4 D stick to the equipment they are mixed in and it is almost impossible to completely get rid of the residue, or to reuse the container for anything else. They recommend using a dedicated sprayer. Do you want residual like this resting in your sprinkler system that is piped to your house potable water?

If you think there is nothing wrong with what you are doing, please call your town's plumbing inspector and tell him what you are doing. If you are afraid to do so, then what does that say? Who knows, maybe he will have a suggestion that will work for you. I'd be interested to hear his reply.

Before you had posted that, I was reading reviews and the labels on some of the weed killer. I am not even sure I want to use it at all. So I am thinking of just continuing the 1" of water, mowing high, and fertilizing with urea and hopefully weeds do not overtake my lawn.

You say that the 2,4,d residue sticks to the equipment, does the same hold true for the pre-emergent? I ran pre-emergent through sprinklers once in spring and I am nervous. Hopefully that is cleared out of there by now. What do you think?

What about Urea. Certainly not the norm to run through sprinklers, but shouldn't raise any health concerns, correct?

What was the name of the pre-emergent you used?. From my experience pre-emergent is best applied with a sprayer type device. You need to accurately apply it so that the pre-emergent is covered every where.

This was the stuff.
http://www.amazon.com/gp/aw/d/B004GTQBEK/ref=mp_s_a_1_9?qid=1464701835&sr=8-9&pi=AC_SX236_SY340_FMwebp_QL65&keywords=pre-emergent+herbicide

So you applied Prodiamine 65WDG as your pre-emergent. Did you read the application procedure? As per my understanding, this cannot be effectively dispensed thru your lawn sprinkler system. It needs a tank-sprayer type applicator. I am guessing, that the pre-emergent application was not uniform in your yard. You will be able to say for sure, when the crab grass season starts mid June. If the crab grass is popping up every where, you can be certain that the pre-emergent protection was not available.

tye said: You say that the 2,4,d residue sticks to the equipment, does the same hold true for the pre-emergent?

I'm not really sure. I read the comment about 2,4 D from the label instructions. I don't recall something like that from my prodiamine, but I wouldn't be surprised. It might be worth calling the manufacturer and 'splaining what happened.

Tell me again what is wrong with just spot spraying the weeds? I use Weed B Gone with the little motorized sprayer. Works very well. I don't recall the size of your lot, but if it is big, you could just do a section a day, and then backtrack a week later for weeds you missed. Also, herbicides do stress your lawn even if they say they won't harm the grass. If you don't have to to a wide broadcast it is better to spot spay where needed.

Aluvaboy: I did read the application procedure. I figured out the amount of pre-em to be used per square foot. I took that amount, disolved it in about 8 gallons of water. I divided it in half and ran 4 gallons across the lawn through the sprinklers. I did the other 4 gallons about 3 days later. I just wanted to make sure the grass didnt die thats why I did it twice. As for if it worked or not, I guess time will tell in June, so I will report back with results.
I think I got a pretty even coat on the lawn, but if what I did doesnt work, Im guessing its because the tank sprayer probably would have been more concentrated. Running through the sprinklers probably dilutes the heck out of the mixture.

Today I ran 2lbs urea per 1000sqft through sprinklers. I divided it in half like I did with the pre-emergent so i guess really all I did was 1lb of urea per 1000sqft so far. I will apply the second half of urea maybe in a few days or so to make sure I didnt burn the lawn lol. Im too scared to put the whole 2lbs at once, but Im guessing again that the extra water that it mixes with through the sprinklers makes it very diluted. We will see. Right now my lawn is dull green. Everone elses in the neighborhood is deep dark green. They fertilized a little early I assume. I will report back on how the urea did. Anyone know how long before I see deep green results or if I burnt it? How long before I can be confident that the first half didn't do damage so I can apply the second half?

Danielj: I dont think I will run pre-emergents or post-emergents through the sprinklers ever again. The point you made about the residue staying in pipes even after flushing got me nervous. I will however do the urea if it works. Im sure urea will flush out nicely, what do you think?

To answer your question, there is nothing wrong with spot spraying. I originally wanted to make it easy doing it through sprinklers. I think I will try the spot spraying technique actually since you scared the heck out of me lol, if I do even decide to use it at all. Will the weeds eventually take over my lawn if I don't use any pre or post emergents, and just water, feed, and mow properly? Oh and the lawn is half acre btw.

Slight overdose of Prodiamine will not kill the grass. It's job is to retard/prevent the germination of any viable seeds that are already in the ground waiting for the right conditions to germinate. For example, crab grass seeds that were dispersed by the crab grass from last season are already in your lawn. When the temperature is consistently in the 80's and when there is enough moisture and sunlight, these seeds will germinate.Timely application of pre-emergent will prevent these from germinating. So in a few years all those seeds will not be viable and since no more new seeds are inducted into your lawn, your lawn will become weed-free. I had a lawn similar to yours and weeds were a real headache. Now after following the advice from this forum, my lawn looks gorgeous. I have posted pictures of my lawn in this forum. So slight overdose of prodiamine pre-emergent will not harm your lawn. It will be a problem, if you plan over-seeding/re-seeding in the fall. The pre-emergent will not differentiate between grass or weed seed. Grass seeds will not germinate. Prodiamine if applied properly has a 6 to 8 month effectiveness.

While I agree with the statement above, it depends on how strong he mixed the prodiamine. With the link he showed, it was the dissolvable granulars so depending on the strength of the mixture, the effectiveness time period would vary. And applying via the irrigation is not even so lots of variables here

tye, I don't know about urea staying in the piping or not. Does pee stay in your sewer line? :)

I think this discussion about tying into your potable water system is a perfect illustration of why it shouldn't be done. There are general practices or principles in engineering that just shouldn't ever be violated. For instance, when you design a pressure vessel (even something like a pressure cooker) you install a relief valve that will relieve the pressure before you reach the vessel's rated pressure. Having that pressure relief is a generally accepted (actually a law) practice that shouldn't be violated. In addition, the vessel will actually be manufactured to withstand double and maybe triple the rated pressure. That is another accepted practice.

In our discussion, we're talking about the practice of not intermingling any chemicals with your potable water system at home. It is just a principle that just shouldn't be done. The perfect example in your case is that, honestly, you thought it was all hogwash and you were going to do it again anyway. What you found out was something you couldn't have realized... that some of the chemicals you use might stay around in your piping for a long time. So that's a good example of why you just don't do it. Things happen that you can't predict. Urea might be fine, but it violates the general practice.

I'm not a lawn expert. I've been coming here for about 3 years now and learn what I can. I'd say if you mow high and water properly you will minimize weeds. However, especially with a newly developing lawn, I think it will take a couple of seasons of active weed killing to get a handle on it. You may also find it difficult to get grass in all areas to grow enough to mow it to 4 inches.

tye22tye,

Pictures of my lawn.

Nice pictures of the lawn tyetye. Looks like it might be a bumpy ride in places. Have you considered "leveling" it?

I agree that weeds should be spot sprayed. Liquid herbicides are meant to be misted onto the leaves, not drenched into the soil. Running it through a fertigator system would be both a waste of chemicals and likely an environmental mess as the chemicals seep through the ground.

Thought this was a good weed killing vid: https://www.youtube.com/watch?v=HGTZeXMrfH8

The idea is spray a couple times a year tops, and this should be enough to keep them at bay. I know it's a lot for the first kill, but after that its just maintenance.

Ok, so I think I will get this:

https://www.amazon.com/gp/aw/d/B00MKB69IE/ref=cm_cr_arp_mb_bdcrb_top?ie=UTF8

Anybody's thoughts? Danielj?

Aluvaboy.....nice lawn!

I buy a one gallon concentrate from "domyownpestcontrol.com". The name of the weed killer is 2,4,D with triclophyr. I use a tow behind 14 gallon sprayer and the rate of application is 2 ounces per gallon. I have an acre property and using a manual pump sprayer is not easy. My tow behind sprayer has an electric 12 volt pump and 2 booms with nozzles. The application is effortless. This stuff should take care of most of your broad leaf weeds including dandelions and clover. In your case, I strongly recommend using a pump sprayer and not use your "fertigation system".

@aluvaboy - can you post a link to what you bought? I see a bunch of options there and the prices are very different.

so you mix it up and spray on the lawn, with no damage to the grass?

Would you suggest the weed be gone or something like this:

http://www.domyownpestcontrol.com/crossbow-specialty-herbicide-4d-triclopyr-p-4545.html

tye, a lot of people use Weed B Gone CCO, which kills all the stuff Weed B Gone kills, plus clover, chickweed and oxalis, "CCO." The difference is that the regular WBG is available in a little motorized spray bottle, while you have to mix your own solution of the CCO. I think mixing your own is a better option. In this way, you can either spot spray individual larger weeds, or you can broadcast spray a larger patch of clover. It worked well for me last year. Also, go with the 2 gallon pump sprayers instead of the 1 gallon. The 1 gallon runs out too fast for my liking. In your case with 1/2 acre you could justify the 4 gallon backpack battery powered sprayers. I looked into them and just decided to stay with the 2 gallon hand pump for now. Looks like some people have problem with leakage, etc. with the back packs. Not sure how well they are made. I have 9000 sf of lawn plus mulch areas so I can get by. If I had the 1/2 acre I'd probably invest in the 4 gallon anyway.

http://www.ortho.com/smg/goprod/ortho-weed-b-gon-chickweed-clover-oxalis-killer/prod70214

Thank you, that does help. My lawn is just as described here and I don't think the prodiamine is holding off all the weeds so this sounds like a good option. I'll be doing a Reno on my back yard this fall so I might as well buy the bigger container as I'll have about 25k of yard then!

There's going to be break through for various reasons. I'm getting weeds where the dang squirrels keep digging in the grass, what for god knows. I imagine there might also be insects/spiders etc that dig and break the pre-emergent barrier. Still, I'm getting about 98% protection with the prodiamine, and breaking the seed cycle is going to be huge.

Yeah I expected weeds for the first two years due to it being new soil and the such. It'll be nice to brake the cycle and i think killing the weeds before they "seed out" can really help too.

I just bought the Crossbow and the surfactant so soon they will be dead.

I have a 16oz bottle of the WBG OCC and was disappointed to see it only treated 3,200 sq ft!!

For what it's worth Crossbow is not labeled for home lawn use. Also, the ester formulations of herbicides usually do not need a surfactant. There are plenty of 3 way broadleaf herbicides that are cheap and labeled for use on home lawns, that would be just as effective.

joneboy,

I just read the outsert from crossbow bottle. I was unable to find the specifics that it is not labeled for home lawn use. I have tried quiet a few weed killers over the years. I find this brand reasonably priced and effective and to be more effective when applied along with a surfactant. Also there are two types available. One is just the 2,4, D ( the ester formulation you mentioned). The other is 2,4, D with triclophyr. I use the latter type and find it very effective against clover and dandelion. Can you suggest a few that are cheaper and equally effective?

I was unable to find the specifics that it is not labeled for home lawn use.

Herbicide labels are "exclusive", if the label does not explicitly permit it, it's not allowed.

“It is a violation of federal law to use this product in a manner inconsistent with its labeling.”

Aluvaboy, if it's not specified on the label then you can not use the product in that area. The label is the law. J4c11 It is a violation of federal law to use this product in a manner inconsistent with its labeling.”. This means you can not use any pesticide in a manner that is not specified on the label. Suggestions, Trimec Classic is cheaper by the gallon than Crossbow, Fertilome and Southern Ag make pint size options of Trimec that are cheap. You can find these products on your domyownpestcontrol.com. One other point that Crossbow herbicide is very effective but it's not really made for your application it's more for clearing woody brush areas. What your using it for is like killing a fly with a baseball bat.

Hello,

So I used the weed b gone in a backpack sprayer yesterday and sprayed all the weeds in t he yard at 2oz per gallon. The bottle says results in hours, but I just checked this morning and it looks like it had absolutely no effect whatsoever on the weeds. I'm not expecting them to vanish overnight but I figured they would be atleast wilted. Anyone have any idea why nothing at all?

I think you'll see it in about 3 days, then around 2 weeks it should be dead

Yeah, hours is just marketing, but you'll see it in a few days

Ok Thanks. I sprayed about 6pm yesterday and this morning I went to take the dog to the bathroom not realizing that we were walking on the grass that I had sprayed the day before. This was about 7am. The grass was wet from the morning dew, so I was wondering if this is bad that I went back in the house?