Is it too early? Current soil temp 5 day average is ~40f. Next 10 days it will likely hit the 50-55f range in zone 6b. Plan is split application of granular dimension about 5-7 weeks apart.
The common lawn pre-emergents (prodiamine, pendimethalin, and dithiopyr) work to help reduce the germination of certain seeds… Mostly grasses and only a handful of broadleaf weeds. The labels will list which weeds are targeted. To prevent more broadleaf weeds, a specialty broadleaf pre emergent like isoxaben is required.
Pre-emergents work by preventing the germination of seeds of the target species. So in order to be effective, a pre emergent needs to be applied BEFORE those seeds germinate. For winter annual weeds (annual weeds that are present in the fall, winter, and spring, like poa annua), a pre emergent needs to be applied in the fall before soil temps fall below 70F. In order to prevent summer annual weeds (like crabgrass), a pre emergent needs to be applied in the spring before soil temps reach 55F. (In very southern areas, timing can be more closely tied with periods of higher moisture AND climbing soil temps. Consult your state extension service for more specific guidance)
Pre emergents will not kill existing weeds. Pre-emergents alone will rarely control a weed problem. Pre-emergents are tools to **reduce** the need for post-emergents. They rarely eliminate the need for post emergents.
The labels of pre emergents have many important instructions and use restrictions. ALWAYS READ THE ENTIRE LABEL. For example, you are limited to 2 applications of each active ingredient per year.
*I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/lawncare) if you have any questions or concerns.*
OldSoul93_
Why is it that in East texas it only wants to rain mostly on the weekend!!!!
DrDuckling951
Check the package instruction. There should be a range of soil temperature for the pre-emergence to activate.
My Scotts crabgrass preventor (southern lawn) just say to use it when rain/irrigation is expected and soil temp is below 80F.
exmodrone
The local True Value here has “it’s time for Scott’s step 1” on their marquee but it seems too early. It’s in the 30s-40s here.
Uncivil_Procedure_
What preemergent are you planning on using? If you’re using prodiamine or dithiopyr, you’ll be okay unless your area typically gets significant rainfall over the next month. If you’re using pendimethalin, I’d wait until your soil is 53F at the 4″ depth and consistently rising regardless of rainfall amounts.
Although I don’t think it’s always accurate, GreenCast has a soil temperature tool that will better determine your preemergent timing. [https://www.greencastonline.com/tools/soil-temperature](https://www.greencastonline.com/tools/soil-temperature)
Walton1993
Why not look at your local soil temps?
ssh-exp
I did it yesterday (Denver Front Range)!
Logi_Berra92
6a here. I bet by end of next week will be perfect timing with that rain as well 👍
joeco316
I’m a big advocate for erring on the side of doing it too early. I’m also a big advocate for doing 2 applications, one on the early side and then another ~6-8 weeks later.
MartyMailboxxx
We’ve been applying Crew and Prodoxaben in CT all week at our nursery. About 40 degree weather here, but double check your soil temps. Thursday or Friday might be a good day to apply pre emergent.
Motor_Antelope_7564
People over think this so much it’s crazy. It’s put it down BEFORE 55 soil temp. You can put it down when the soil temp is colder doesn’t have to be rocket science it lasts in the soil for a long time.
TheKettleGuy_dot_com
Personally I’d put half down and then the other half in a couple/few months
Nope, Im in the same region as you and applied my preemergent a week ago. Use the free water on saturday and this will help you break down the particles
14 Comments
The common lawn pre-emergents (prodiamine, pendimethalin, and dithiopyr) work to help reduce the germination of certain seeds… Mostly grasses and only a handful of broadleaf weeds. The labels will list which weeds are targeted. To prevent more broadleaf weeds, a specialty broadleaf pre emergent like isoxaben is required.
Pre-emergents work by preventing the germination of seeds of the target species. So in order to be effective, a pre emergent needs to be applied BEFORE those seeds germinate. For winter annual weeds (annual weeds that are present in the fall, winter, and spring, like poa annua), a pre emergent needs to be applied in the fall before soil temps fall below 70F. In order to prevent summer annual weeds (like crabgrass), a pre emergent needs to be applied in the spring before soil temps reach 55F. (In very southern areas, timing can be more closely tied with periods of higher moisture AND climbing soil temps. Consult your state extension service for more specific guidance)
Pre emergents will not kill existing weeds. Pre-emergents alone will rarely control a weed problem. Pre-emergents are tools to **reduce** the need for post-emergents. They rarely eliminate the need for post emergents.
The labels of pre emergents have many important instructions and use restrictions. ALWAYS READ THE ENTIRE LABEL. For example, you are limited to 2 applications of each active ingredient per year.
*I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/lawncare) if you have any questions or concerns.*
Why is it that in East texas it only wants to rain mostly on the weekend!!!!
Check the package instruction. There should be a range of soil temperature for the pre-emergence to activate.
My Scotts crabgrass preventor (southern lawn) just say to use it when rain/irrigation is expected and soil temp is below 80F.
The local True Value here has “it’s time for Scott’s step 1” on their marquee but it seems too early. It’s in the 30s-40s here.
What preemergent are you planning on using? If you’re using prodiamine or dithiopyr, you’ll be okay unless your area typically gets significant rainfall over the next month. If you’re using pendimethalin, I’d wait until your soil is 53F at the 4″ depth and consistently rising regardless of rainfall amounts.
Although I don’t think it’s always accurate, GreenCast has a soil temperature tool that will better determine your preemergent timing. [https://www.greencastonline.com/tools/soil-temperature](https://www.greencastonline.com/tools/soil-temperature)
Why not look at your local soil temps?
I did it yesterday (Denver Front Range)!
6a here. I bet by end of next week will be perfect timing with that rain as well 👍
I’m a big advocate for erring on the side of doing it too early. I’m also a big advocate for doing 2 applications, one on the early side and then another ~6-8 weeks later.
We’ve been applying Crew and Prodoxaben in CT all week at our nursery. About 40 degree weather here, but double check your soil temps. Thursday or Friday might be a good day to apply pre emergent.
People over think this so much it’s crazy. It’s put it down BEFORE 55 soil temp. You can put it down when the soil temp is colder doesn’t have to be rocket science it lasts in the soil for a long time.
Personally I’d put half down and then the other half in a couple/few months
YES
https://preview.redd.it/h68tozcepdne1.jpeg?width=1280&format=pjpg&auto=webp&s=d44960ea8789a8017879553aa01905abfc24cbb7
Nope, Im in the same region as you and applied my preemergent a week ago. Use the free water on saturday and this will help you break down the particles