Application timing of Pennington Pro Care Crabgrass Plus 22-0-6 .25 Uflexx .172 Dithiopyr will vary by region and the best person to ask about application timing is your local master gardener who works at your local cooperative extension office. Pre-emergents are generally applied in both the Spring and Fall for the best control.
Most likely you would want to put down the Pennington Pro Care Crabgrass Plus 22-0-6 .25 Uflexx .172 Dithio in the spring. However, you didn't state what type of turf you are treating, or if you are doing any reseeding? There are other elements sometimes that can determine which would be the best time.
Irrigation or rainfall within 7 days after application may improve weed control of Pennington Pro Care Crabgrass Plus 22-0-6 .25 Uflexx .172 Dithiopyr Turf Fertilizer.
Pennington Pro Care Crabgrass Plus 22-0-6 .25 Uflexx .172 Dithiopyr can be applied to established (residential and commercial) cool and warm-season turf-grass.
If you are using the Pennington Pro Care Crabgrass Plus 22-0-6 0.25 Uflexx with 0.172 Dithiopyr, then you would be applying 0.263 lbs of active ingredient at the 3.5 lb/1000 sq ft rate.