Too late for pre-emergent/ don't bother?

[bazilbrush]

I'm new to the forum, this is my first year of really taking on my lawn. It already seems like I might have started too late!

Lawn description: Located in New Jersey, fescue mix (tho with some other grasses in there), 15,000 s/ft. Lawn is green and looks OK from a distance, but a closer look shows that things aren't ideal - There are some small bald spots and various weeds in different areas. I'm dealing with a large amount of clover, some poa a, and multiple patches of a strange, woody, clumpy sprawling grass that is awful and seemingly common in NJ. I plan on taking core samples/ sending the soil in to Rutgers for a soil test to help guide a fertiliser strategy. I might also send a sample of this clumpy grass to find out what it is.

I over-seeded 3 weeks ago (I didn't know any better) and put down Millorganite. I applied Tenacity to the clover and poa a 8 days ago. Eliminating the clover has been a priority as it annoys my wife. My tenacity application wasn't ideal and I probably missed a few spots (I used a hand pump). So far the clover isn't showing much sign of stress, so I'm considering doing a blanket spray of Tenacity using a battery backpack sprayer this weekend.

I haven't applied any pre-emergent. Is it too late to do this/ not worthwhile given that i over-seeded/ still worth doing? Would I need to take soil samples before I do this or doesn't that matter? Thanks.

[Green]

It's not too late to get partial control (since all the germination doesn't happen in the first few weeks of crabgrass season...far from it).

However, the fact that you overseeded means you should not apply a pre-emergent so soon. You'll need to wait a while on that.

You can blanket spray Tenacity (again??) 4 weeks after the first app, but you need to wait until any new grass from the overseed has been mowed at least once or twice if you don't want to lose it.

Another option (still, not just yet, but after the new grass reaches a certain point) is an app of Quinclorac (like Tenacity, it will act as both a post and pre-emergent). Tenacity and Quinclorac (e.g. Drive 75) will only have a robust pre-M effect for 4 weeks or so, though.

But you definitely have options.

Do a risk assessment. Is crabgrass your major enemy? Or broadleaf weeds? Prodiamine and especially Dimension aren't the greatest against a whole lot of broadleaf weeds. Gallery (Isoxaben) is the pre-M of choice to prevent broadleaf stuff, but nothing against grasses.

If it's crabgrass you're after, an app of Tenacity or Quinclorac after the appropriate interval for new grass maturation status (read the labels), followed by a regular pre-M 3-4 weeks later, is one of your many options. (Tenacity also controls broadleaf weeds far better than Quinclorac, which is essentially a crabgrass herbicide.)

[bazilbrush]

Thanks. I should clarify how I used the Tenacity. I employed it as a post-emergent treatment for the clover patches (mixed with surfactant). I also sprayed the poa a patches (though I didn't realise that is what they were at the time) and sprayed the areas where I have this clumpy, woody grass (might be poa T, orchard grass, a sedge of some sort, really not sure). That grass is now turning light green. On reflection I wish i had blanket sprayed, as I have treated about half of the lawn but in a non-systemic manner.

The initial enemy has been clover, since that really took over last year. However that seems easily treated (I used Tenacity, though I now see that there were other options). Now the enemy is shifting to this other grass as it is really unsightly in spring (purple base, woody feel, growing sideways in all directions).

I would be using a pre-M to contain crabgrass, as I do get issues with that later in the summer. I have Prodiamine ready to go, so it sounds like I should put that down in 2-3 weeks once the new seed is more established.