Probably going to do 1/2 and ½ later. It’s been warm here. Was going to start April 1. Using Andersons Crab Grass. Northern Colorado/Cheyenne are. Or wait? Thanks.
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 isoboxen 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.
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GangstaRIB
Grab a thermometer and jam it in the soil.
Saint_Dogbert
Already had TruGreen throw down Barricade Friday….
Farpoint_Relay
I don’t think there is really a reason to mow before putting down a pre-emerg… You want it to get watered into the soil well, that’s about it.
FloRidinLawn
What are soil temperatures
BikingEngineer
I like the [MSU Tracker](https://gddtracker.msu.edu/) better. It gives a useful visualization of application timing that works better with how my brain works.
Arth3r911
If is granular pre emergent just wait for a day before rain
tjt169
Zone 8b spraying next weekend
WorldClassAwesome
I’m also NoCo, with the same pre emergent, wait until late March or even early April. I know the great weather lately has me wanting to get out in the yard too but the soil temperature won’t hold.
9 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 isoboxen 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.*
Grab a thermometer and jam it in the soil.
Already had TruGreen throw down Barricade Friday….
I don’t think there is really a reason to mow before putting down a pre-emerg… You want it to get watered into the soil well, that’s about it.
What are soil temperatures
I like the [MSU Tracker](https://gddtracker.msu.edu/) better. It gives a useful visualization of application timing that works better with how my brain works.
If is granular pre emergent just wait for a day before rain
Zone 8b spraying next weekend
I’m also NoCo, with the same pre emergent, wait until late March or even early April. I know the great weather lately has me wanting to get out in the yard too but the soil temperature won’t hold.