The most effective use of Tenacity is to apply just before germination,soil temp 55, of any summer annuals. One reason for the limit on the amount of Tenacity is to help prevent development of resistance to the herbicide,

Thanks for the info Joneboy. However I do have a follow up question.

Does the pre m with siduron contain tenacity or is it a separate chemical altogether?

Thanks

The pre emergent herbicide Tupersan which contains the active ingredient siduron. Tenacity contains the active ingredient mesotrione. Tupersan and Tenacity are two separate products containing two different active ingredients.

Thanks Joneboy !

One more follow up question. Can siduron be put down on new KBG seed that was dorment seeded in late February?

Yes you can use siduron. Two apps three to four weeks apart, then Dimension at the low rate to get you through the rest of the season. Also, you will need to invest in a broad leaf herbicide to control all the weeds that siduron does not control. You may also want to put down some perennial rye grass to compete with weeds and a fine fescue because you said the area is in a shady spot.