I've recently started getting into organic lawn care this year and stumbled upon this site. I'm no expert but I try my best to care for my lawn after firing my lawn care service 2 years ago. They were chopping my Tall Fescue lawn down to about 1 1/2 inches and overcharging for extra additives in the spring and fall. I decided that I would care for my lawn myself.
I have read many great ideas on this site and tried them out this year to help keep my lawn chemical free. In March after the snow had melted off my lawn I noticed the grass was completely full of thick thatch which I'm assuming was because of the bad winter we've had and the chemical winter fertilizer I applied in late November after my last mowing. I decided to apply organics to my lawn going forward to minimize the thatch in the spring.
Now in May after using alfalfa pellets, Milogranite, organic corn meal, unsulphured molasses with vinegar, baby shampoo since March my lawn looks great! Soon to be applied Texas Tea and Sea Bird Guano. My lawn has looked so much better than the past 3 years of owning my home. The only problem I'm facing now more than the last few years is Poa Annua. It is the only weed growing on my lawn from what I can see. I read about using Pre em but I've missed that window. These are the chemicals I found on Amazon.com: Dithiopyr 40 WSB (Preemergent Herbicide Equivalent to Dimension Ultra UNI1003), Prodiamine 65 WDG Generic Barricade 65 WDG and Tenacity.
So my question is can I still use one of these to kill the current seeds or should I just wait until the late fall to apply? I'm not sure which chemical to use at this point as they all claim to kill Poa. Tenacity kills weeds but I've read that it doesn't kill Poa off as well as the others do and it also leaves white patches on the lawn. My lawn area is so small that I'm not sure how much to use of the concentrated chemical without harming the lawn or using too little that it won't kill off the Poa. I have a shared roughly 50 sq ft fescue lawn in zone 6 in Staten Island, NY. If this will brown (or whiten) my lawn for the next month or so in order to kill off the Poa I would rather wait until the fall. My neighbors on the entire block are infested with Poa. Is it even worth fighting it off? Also, I have no idea where to send a soil sample off to as Google isn't that helpful. If anyone knows of a place where I can send a soil test I would greatly appreciate it.
Thanks for any advice.