Planted grass seed 3 weeks ago. The grass is well over 6 inches; however, I read that I should wait 4 weeks before cutting.
Should I keep waiting?
Time to mow and wait no longer! Mow when the grass is dry with the sharpest blades you can make happen. Bag those clippings. And most importantly, do not mow any shorter than 3". Best is 3 1/2". If you wait any longer you'll be taking off so much of the blade you will stress your grass greatly and that you do not want to do especially for the virgin mow.
Our site has a ton of the best information to manage and grow healthy lawns. I haven't found a site that is at all close to this one for REAL information. Please read the question answers about lawns as soon as possible. I got to know this creature called a lawn (cool season grasses) very well and the information put out by Scott's Ortho...is so lame and it is obvious they want you to fail. I took care of lawns on a commercial basis for decades and I couldn't fail.
Read more of our stuff and please keep asking questions...we can help you have the most healthy, green lawn in your neighborhood I kid you not! Watering! Water very deep ONLY when your lawn needs it ( there is a super way to tell) Very big deal. Fertilizer, critical to know and not over do!! Changing mowing patterns. And no lower than 3" and we explain WHY.