Just looks like a broadleaf weed. Not much you can control it with now since you just planted aside from manually pulling it out.

I would let it be. Aerate and Reseed the kbg blend in the fall.

Then next spring you can do a better weed control if needed.

How much sun does that array get? KBG loves sun.

 

View attachment 361562 View attachment 361563 View attachment 361564 View attachment 361565 Hello,
I have just planted a lawn of kentucky bluegrass blend from seed superstore recently. The lawn in currenty 20 days in from initial planting of seed. Now a week or so after i noticed germination there was a small patch of lime green that appeared. Wel now its spread to a fairly large patch of lime green and it aint grass. What the hell is this stuff and should i be worried.

What is your location?
It looks like crabgrass seedlings taking hold.

 

This patch is in my backyard and recieves easily over 4 hrs of direct sunlight a day. I live in upstate new york. Thanks for the help.

 

100% it is new Crabgrass plants growing..

 

It sure looks like crabgrass to me. Check the label but from memory, quinclorac minus surfactant is safe over KBG a week after KBG emergence. It should zap that baby crabgrass.

Spring is a tough time to seed KBG especially. Keep it hydrated and as cool as possible when summer heat arrives. Good luck! Please check back in fall and let us know how it does.

 

Now i am 3 weeks into planting this new kbg lawn so im assuming that im just starting to get germination on that strain. Is it still wise to put down the quinclorac 75d nowish. Or should i wait.

 

I checked the label; my memory was faulty - I must have been thinking KBG before seeding. For KBG it's wait a week after application before seeding; wait a month (28 days) after emergence before application. I'd wait. And read the label .

You definitely have grass well emerged in a lot of areas. That's not KBG yet? What did you plant?

 

Tenacity can be applied after 2 mowings. Or at time of seeding.

Spring is a tuff time to grow kbg from seed. Be ready to overseed this fall.

 

View attachment 361562 View attachment 361563 View attachment 361564 View attachment 361565 Hello,
I have just planted a lawn of kentucky bluegrass blend from seed superstore recently. The lawn in currenty 20 days in from initial planting of seed. Now a week or so after i noticed germination there was a small patch of lime green that appeared. Wel now its spread to a fairly large patch of lime green and it aint grass. What the hell is this stuff and should i be worried.

i agree chis your have the best steps to follow pant and lawn care

 

Yeah so i got a blend from seed superstore that had some rye grass and fescue in it as well so thats what im assuming shot out of the gate. Im not sure why its so spotty looking as to whats growing. Is it because the kbg has not yet shown up? I seeded by hand so would that have a effect on it, possibly i just didnt get a even spread?

But after research apparently i cant even purchase quinclorac in the state of new york because of some regulations. So is there something i could get on there post emergent style that wont kill off the turf grass. Im at a loss here. Need expertise

 

... But after research apparently i cant even purchase quinclorac in the state of new york because of some regulations. So is there something i could get on there post emergent style that wont kill off the turf grass. Im at a loss here. Need expertise

There is nothing I have found safe for newly emerged KBG, New York or not. Even carfentrazone requires at least 7 days post emergence. Mesotrione (tenacity) requires a month. Be patient and deal with the weeds once you're confident the grass is up and growing.

For whatever it's worth you are learning valuable lessons. There are lots of reasons for pre in Spring and seed in Fall. This is one of them. I understand it doesn't always work out so nice and neat when you're looking at bare dirt in March and want a lawn growing on it but to keep it in perspective, you've laid out a great challenge for yourself and it will take a lot of work and patience to see it through. Whatever doesn't work out can be reseeded in late summer / early fall. Just look at it as a learning experience and don't stress over it. In the mean time research what selectives you can get where you are and make a plan for when the grass can handle it.

 

You can use tenacity after the 2nd mowing.

 

How long to wait before i mow. I mean do i wait untill im certain the kbg has had enough time to germinate.

 

Best to wait till grass is 4-5 inches tall. Might be 8-12 weeks.

 

Chris, Just wondering...did you have soil/loam brought in for your new lawn?

 

When we bought the property there was a large flower garden in place. So the soil was pretty rich from all of the garden soil that was used. I ripped out the garden, deweeded, and the tilled in a bit more topsoil

 

I only ask because sometimes when loam is brought in it can be loaded with crabgrass seeds.

 

Now this tenacity will it work just as well once the weeds grow in size. Since im a few weeks out from mowing so i figure the weeds will have a stronghold by the time im able to apply any post emmergent. Thanks for all the help, first time homeowner trying to make somethingf of his backyard.

 

Experiences will differ, but I planted some Bewitched KBG on May 5th and I observed sprouts on May 15th. The average soil temperature in a sunnier part of my lawn during that time was 57 degrees F.

I'm sure that not all the seeds germinated that quickly.

Here is a chart of expected germination times for different grasses.

http://ipm.ucanr.edu/TOOLS/TURF/ESTABLISH/germin.html