If you don t water it in you re essentially using it as a post emergent. This is why we recommend a total of 3 applications.
Lawn Soil Temperatures And Effects Lawn Care
Pre emergent granule will remain most effective in the soil for 45 days after application with limited effectiveness for roughly 2 to 3 months.
Soil temp for pre emergent. Twice in the spring when the average soil temperature warms to 55 degrees with a follow up application 45 60 days later. It should be noted that tenacity only lasts a few weeks in the soil and it s not the best pre emergent. Your soil temperature should be below 70 degrees and dropping.
The best time to apply a pre emergent herbicide to your lawn during the fall season is between the months of august and november for both warm and cool season grasses. You are very observant. The general guide is to get the application down before the top 2 of soil are 50 55 degrees fahrenheit for five or more consecutive days.
Get automated soil temperature alerts for key pests delivered by email. It needs to reach the soil to work as a pre emergent. For maximum pre emergent herbicide effectiveness apply spring pre emergents once soil temperatures have remained at 55 12 for 2 3 days.
When to apply pre emergents in the fall. To apply tenacity as a pre emergent you want to blanket spray the whole lawn and then water in the application. Pre emergent application timing tips timing is everything especially when it comes to the application of pre emergent herbicides like lesco s stonewall to control summer annual weeds.
When using fall pre emergents apply them when soil temperatures have dropped to 70 21 for 2 3 days. Today s average 12 7 2017 63 5 year average 2012 2017 65 10 year average 2007 2017. And once in the fall when the average soil temperature drops to 70 degrees.
My usual recommendation is to put out pre emergent in early march but there s nothing wrong with applying it in mid february. Crabgrass seedlings emerge when soil temperatures hit 55 degrees for a few days and the trend is higher. Soil temperatures when to apply pre emergent in spring summer weeds like crabgrass must have several consecutive days of temperatures above 55 degrees before they germinate.
In past years this has happened in late february and early march. If the seed is right on the surface of your soil it becomes warm quickly. Average soil temperature on december 7th in greensboro nc 27419.