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Help on Pre emergent timing!

Posted by Roger505 Apex,NC (My Page) on
Wed, Feb 19, 14 at 21:18

Hello everyone! I'm in North Carolina and completely started over in the fall with tall Fescue

(See Original Lawn thread at the bottom)

I am still fairly new to lawn care schedules & wasent even thinking about pre emergent yet because we had like 6 inches of snow on the ground last week! However today was 70 & I am leaving out of the country for 2 weeks on Saturday. I'm freaking out a bit about what to do because I don't want to miss my application window. I haven't ordered one of the good pre emergents yet so if I want to put anything down before I leave it will be from a big box store. I tested the soil today with a digital meat thermometer and its reading 50-51 deg which is pretty close to application temp I believe.

So my options are
1.) Get the best pre emergent I can find locally and apply before I leave (Lowes or HD will probably be my only options as I will be at work 8-5 until I leave)

2.) Order something good online like Dimension or Barricade and apply when I return back (March 9th).

P.S. I also have some small Henbit in some areas I would like to apply post emergent to before they really start growing. I bought some Spectracide concentrate online that contains 2-4-D, Dicamba, & MCPP. Should I also apply this now ?

Thanks everyone in advance for your help & advise!


Here is a link that might be useful: Original Lawn Thread

Follow-Up Postings:

RE: Help on Pre emergent timing!

Apply the pre-m when the Forsythia bloom.

Apply post-emergents when the weeds are actively growing.

RE: Help on Pre emergent timing!

I dont know specifically where any Forsythia is planted around me, but I looked it up and it says it blooms in late Feb/early March in my area.

This has been a colder winter so maybe I'll be ok applying around March 9th when I return. Any other opinions?

RE: Help on Pre emergent timing!

Order dimension apply when you return. Spray your 3 way product when you have a few days in the 60s. The henbit my take a couple of apps.

RE: Help on Pre emergent timing!

Thanks Joneboy I took your advise and will be applying when I return to the states. I've been researching dimension and trying to figure out what to order. I see some granular products that contain dimension, the liquid form from Dow (Dithiopyr 24%) in the link below ($139) & a generic version Dithiopyr 40 WSB 20oz ($80). Not sure how the the quantities compare but $80 is certainly sounds better.

Also I have another concern about the dimension possibly damaging my lawn. I seeded later (nov 4th) and my Fescue did grow in quite well but it never had a chance to get long enough to cut (even once) before it went dormant for the winter at about 2.5-3".

According to the dimension label I should have at least 2 mowings following seeding. Although I think possibly in my case my roots are probably developed just as much or more at this point then a typical newly seeded after two mowings .

From the Dimension label
"Use Dimension 2EW on seeded, sodded, or sprigged lawns and ornamental turfgrass that are well established. Newly established turf must have developed a good root system and a uniform stand, and have received at least two mowings following seeding, sodding, or sprigging before making the flrst application of this product. Use of this product on turf that is not well-established, or has been weakened by weather, pest, disease, chemical, mechanical or other related stress, may result in turf injury"

Do you think using Corn Gluten Meal would be a good alternative in my case this first season?

Here is a link that might be useful: Dimension link

RE: Help on Pre emergent timing!

I'm no expert, but I'd look at it like this:

If the new grass from last year wasn't well established before it went dormant, then this winter probably killed and/or damaged it anyway. Whatever of it was established enough to make it through this winter is probably established enough to take a pre-m.

Just my $0.02. Somebody smarter than me probably has a better opinion.

RE: Help on Pre emergent timing!

I would use Dimension .25 G just for ease of use. If you decide to use one of the other formulations I would by some tracker dye to ensure you don't have any skips, and calibrate your sprayer. You won't see any negative effects on your newly established lawn from the Dimension. No, I would not use corn gluten meal it is a very poor pre emergent herbicide.

RE: Help on Pre emergent timing!

Thanks Joneboy.

When you say use "Dimension .25G" are you referring to the liquid one in the link I posted? "Dimension 2EW Herbicide"? or one of the granule products like "GREEN LIGHT Crabgrass Preventer2 With Dimension" that contains .25% Dithiopyr?

P.S. Do you have any advise for me in regards to fertilizer and application timing? I've read I should fertilize in Feb so should I be doing this around the same time as the Dimension or should I wait a week or two after? I probably should do a soil test to see what my levels are, but would like to hear your thought/advise if you have any?

This post was edited by Roger505 on Thu, Feb 27, 14 at 17:38

RE: Help on Pre emergent timing!

Roger505, I would go ahead and get your soil test done now before you apply products to your lawn. I looked at the soil temps near your area and I think you still have some time before you put out your dimension, here is a helpful web site for soil temps
.25 G is the granular formulation of dimension. I think it is easier for a home owner to get consistent coverage with a granular product. The Greenlight product will work fine. On the other hand if want to combine a couple of applications you could stop by a John Deere Landscapes or Lesco store and get Dimension with fertilizer. Once you do apply the Dimension you will want to reapply again six to eight weeks later and your last application should run out at the end of September (don't forget to water in with half an inch of irrigation), so you can overseed as needed. As far as nitrogen fertilization goes, generally you just want a pound of nitrogen per thousand square feet, in your area, probably around the end of March. However with a newly established lawn you may want to put down a pound and a half split between a couple of applications. To cut down on the number of applications I would get my Dimension with fertilizer and put out a pound of nitrogen that is at least fifty percent slow release. Then maybe beginning of May apply a slow release organic product at half a pound of nitrogen per thousand. The fall, October thru beginning of December, apply two to three pounds of nitrogen per thousand along with any other nutrients as indicated by your soil test from this spring.

RE: Help on Pre emergent timing!

joneboy ,

I'm back in town now! I Dropped off soil samples yesterday for testing. This is peak testing season so they say 1-2 weeks.

Right now I have a bag of Greenlight with Dimension .25G & I also have a bag of fertilizer I bought in the Fall called Classic Lawn food with slow release Nitrogen 16-0-8 (See pics below). I am getting anxious to get the Dimension down so I was thinking about doing it this weekend (meat thermometer 1" down is reading 57 deg).

My main question I guess is whether I should wait possibly 2 weeks for the test results before I get the fertilizer down or at least get a bit down now and amend in a few weeks with the soil results in hand?
 photo 20140308_165422.jpg

 photo 20140308_165439.jpg

P.S. I really screwed up with the chickweed and Henbit I sprayed with the Spectracide 95834 Weed Stop before I left but it appears after reading the reviews the recommended mix (1oz/gallon) is very weak and there was very little damage done. I sprayed again Sunday with 2.5oz /gallon and they are starting to wilt now but its still disappointing.

RE: Help on Pre emergent timing!

The great thing about Dimension is it will kill crabgrass post emergently up to five leaves, before it tillers. So, this gives you a larger margin of error when applying Dimension. That being said, if you keeps you up at night then go ahead and apply the Dimension it's not going to hurt anything. Preemergent timing, along with everything else involved in the care of your lawn, is going to have a learning curve. Use your meat thermometer and measure your soil temp at the same time everyday for three days and record the average temp. Apply your preemergent, then if you get some early crabgrass say in middle to end of April, then you know you applied your preemergent to late and next year you can apply at a lower soil temp. Also, it would not hurt to invest in the herbicide Acclaim herbicide, just in case you make any mistakes with your preemergent application. Acclaim is expensive, but it will last you years. As far as your fertilizer app. goes, I would hold on to the fertilizer that you just purchased and use it in the fall, if your soil test indicates that all the nutrients in the bag are not in the excessive range. Also, just for your edification that bag of "slow release fertilizer" is only around 30% slow release. So if you apply 1 pound of nitrogen per thousand square feet then .7 of a pound of nitrogen will be quickly available to the plant. This is ok in the fall, but in the spring you will be mowing your yard twice a week to keep up. A better option would be .25 to .5 pounds per thousand of ammonium sulfate or urea now. Then when you get your soil test back follow their recommendations plus add .75 to 1 pound of N per thousand that is at least 70% slow release. Henbit usually takes a couple of apps to kill, and herbicides take a little longer to work in the early spring because of the cooler temps.

RE: Help on Pre emergent timing!


Alright so I did get the Dimension down but then it ended up raining for the next three days so I hope it didn't all get washed out. I decided to just order a 1/2 gallon of the dimension liquid because it will be cheaper in the long run and I can spot apply if I see any young crabgrass.

Alight so on the Soil test! I just received the results today. Not really what I expected my Phosphorus levels are off the charts! & my Potassium is pretty high too. My guess is some of that is due to maybe too much starter fertilizer however even my backyard was at 101 and I haven't done anything back there. I guess the PH looks good though.

What are your thoughts and do you agree with the 21-0-0 recommendation? Anything else I should do ?

 photo Front1soil.jpg
 photo Front1amp2.jpg

RE: Help on Pre emergent timing!

The 21-0-0 is ammonium sulfate at a little over a pound of N per thousand this while lower your pH slightly and your make your grass grow like crazy. So apply the ammonium sulfate at 2 pounds of product per thousand square feet now and then another 2 pounds again in three to four weeks. Also, I would apply when there is not any dew on the grass and water in immediately. Your Dimension should be fine, but I would not count on it as a post emergent product for crabgrass use Drive or Acclaim for that. Plus with the size of your yard and since you did use a preemergent you really could pull by hand the one or two plants that might sneak through. If you want to control brown patch I would start looking into Heritage G, or you could let it go this year to see if it is worth it for you. Also, you can just overseed any damage from brown patch in the fall. Only other thing to do is spot treat any broad leaf weeds. Just a reminder, because your phosphorus on your soil test were so high, do not apply any fertilizer with phosphorus.

RE: Help on Pre emergent timing!

Thanks Joneboy. So for this 21-0-0 fertilizer should I still be looking for something this has 50% slow release nitrogen or will something like this work for me?

RE: Help on Pre emergent timing!

Yes that will work . The slow release N was to save you an application and to keep your grass from growing to rapidly. The split apps of ammonium sulfate is kind of the same thing.

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