NFT: Question For The BBI Lawn Experts

your paying to do the work, no?

I'm not sure where you live but here in NJ it's still too early to use a pre emergent. It works best when the soil has reached 55 degrees and mine isn't there quite yet.

As far as seeding it depends on what pre emergent he used. The one I use has to have a four month wait, so I usually seed/overseed in the fall. Some pre emergents can be seeded over after about six weeks but I don't know many that you can before then.

The whole point of a pre emergent is it basically puts a barrier down in the soil so nothing (weeds, crabgrass) can germinate and root. The same would hold for grass seed no matter the quality of seed.

I'd find out what pre emergent he used and do some research on the recommended wait time.

being early is key, IMO. It’s already hitting 60 this weekend and while there will be dips back down near freezing it shouldn’t be prolonged. On 5/1 is can get sneaky hot and mess it up for you.

As for the pre emergent it’s likely fine. My guy would put it down with a certain seed that didn’t effect its growth, can’t remember what it was but it wouldn’t harm the seed he planted.

he put the pressure emergent down early and then did seeding + weed killer. It’s been a couple years so I can’t remeber the order, but either way check again with your guy and ask for a detailed plan.

That’s way too soon to seed - the pre-emergent prevents germination. That’s how it stops crabgrass, and it’ll stop the grass seed too.

For that matter even if the ore-emergent wasn’t applied, spring is an awful time to seed. The grass is still immature when it gets hit by the summer heat, which will kill a lot of it. Fall is the time to aerate and seed.

...you may be throwing money away. We're still getting night time temps down in the 20's and barely scratching the 50's in the day. Soil temps need to reach mid 50's before any pre-emergent goes down (unless you're treating for stuff like annual bluegrass and stilt grass that can germinate earlier) and it looks like it may be another 2-3 weeks at least before we get there. Likewise you want them to be in the low 60's-mid70's for seeding. Without a heat wave that's likely not until early May.

Ignoring soil temps - If he used something like Tupersan or Tenacity for a pre-emergent they won't interfere with new seeding. If he didn't then it's going to hamper things further but the aeration will significantly reduce the effectiveness of the pre-emergent.

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