Fertilizer for newly seeded lawn

[sycorski]

Hello all, I'm a noob to this site and have a question I haven't found an answer for. I have a new lawn (new construction home) located in SW Wisconsin and was seeded on July 22nd. I have an irrigation system. I do not believe my landscaper used any fertilizer when they planted the seeds. I'm now coming up to 4 weeks post seeding and want to know when it's safe to fertilize. I've read that you should wait 6 weeks before you add anything. But ideally I could get one regular application in and then a late season/fall application as well. So question to the group is should I put down an application now? And if so, what? (Starter fertilizer or regular or Milorganite?) Or should I hold off longer and just do one application this year? Thanks for any advice you can provide.

[andy10917]

It's not a big deal. Newly-seeded grass doesn't really require fertilizer until (1) it germinates, and (2) it passes the "sprout-and-pout" stage - it lives off of the "food" in the seed in its early days. Use the Search tool to find more out about Sprout and Pout.

Here's the big question: when did it germinate? It's not that easy a question with a KBG/Rye mix - the PR germinates much faster than the KBG. Did you keep the seeds watered lightly at 2X-3X a day, all the way through the first 3-4 weeks?

Since you don't have a soil test to reference, it's difficult to do more than guess at what fertilizer you'll need - we don't know what nutrients you are lacking. To err on the side of caution, assume that Starter Fertilizer is the best guess. Yeah, it's still quite warm for Nitrogen fertilizer of any real strength, but the die was cast with a July seeding, and now it needs to play all the way out.

We'll tweak and add advice when you supply the germination date(s) (of each type if you know), and the watering practices...

[sycorski]

Thanks for the reply. Yes, I did water twice a day for the first 3 weeks. I've now cut down to once a day, but monitor the soil and its still moist all day long. The seed was a mix of KBG and Rye. The first sprouts happened just 3 or 4 days after seeding. I searched sprout and pout as you suggested as I was not aware of that. Currently, the grass is a lighter green than before...is that a sign of the root growth phase? I was interpreting it as needing fertilizer which is why I posted the question in the first place.

My other area of concern is the varying rates of growth. Some of the grass is a good 4 or 5 inches long already, and other areas are two inches or less yet. Is that expected? How do you determine when to mow the first time? I don't want the tall grass to get too tall, but don't want to mow prematurely on the slower stuff. Thoughts?