Robert from Bremerton writes
I live in western Washington. I would like to reseed my lawn in early September but that also is the time to use this product to control poa annua. Are they compatible together or will this product prevent my seed mixture from germinating?
You would not be able to use Dithiopyr 40 WSB or most pre emergents in the same season that you intend to seed. Since poa annua and cool season grasses are so closely related, there are few products that will kill the poa annua without also harming the lawn. The only one we are currently aware of is called Prograss which can kill & prevent poa and can be applied at seeding, however it can only be applied to residential lawns by licensed applicators. You may want to see if a service local to you can provide this chemical treatment to your lawn. Tenacity is also a pre emergent that can be used at or before seeding, however it only has poa annua seed suppression and only lasts for 30 days. Normally seeding will temporarily need to be done in the spring in order to achieve pre emergent success for poa in the fall.
Answer last updated on: 08/10/2022
