You could try high-lift blades if the dealer did not put those on. And do mow at full throttle, please, it will cut even worse.

JDOwner: Thanks for your reply. What do you mean it will cut even worse?

was the grass damp/wet?

when my grass gets long i get some clipping clumps along the edge of the swath. i can't get away with waiting too long between cuts. i'd still rather mulch than deal with bagging. if i mow about 1.5/week, i can go full speed and get a good cut without clumping.

btw, i have an x304, but mine has no cruise control.

Well the base of the grass may have been wet from dew. But when wet I usually see clumping not dry cliipings. My hunch is that it was the first precision cut with mower in 10 years. In areas where the grass was taller, it did this. In other areas it was clear as can be.

I don't have a X304, nor do I mulch. That said, your grass may be similar to mine which is a pretty varied mix of tall Fescue. What I find, is that the consistancy of the grass varies signigficantly and hence the volume of clippings generated varies, although the grass is uniform in height (before and after cutting) and appears to be fairly uniform in coverage. There are sections of my yard, however, which have more wide blade fescue, than thin blade and vice versa. The wide blade definitely generates a larger volume of clippings. The wide blade clippings also usually appear to be a little "damp" and tend to clump a little. The thin blade clippings appear dry and evenly spread. Just a thought.

Check that your tires are all properly inflated and then that the deck is properly leveled (front to back and side to side per the manual). If you still have problems after these are checked (dealers have been known to make mistakes) then other variables can be considered, but these seem to cause the most issues.

If you are seeing a trail of cut grass when mulching, you are trying to mulch too much material. Basically the deck can't process it all and it drops out. Slow down or raise your cut height a notch. Don't take off more than 1/3 of the plant when cutting, and make sure it's dry. And always run at full throttle.

First, I just wanna be Captain Literal and clarify something. You wrote, "I purchased a Deere X304 (a week ago) having the dealer install a mulching deck/blades." I assume that means you purchased the standard deck with the mulching kit (big black plastic thing under the deck). There are dedicated mulching decks, though I can't recall if Deere makes one for the X304.

Anyway... I bought my X304 at the end of last year and started mulching this Spring (with the mulching kit). Based on my experience, its mulching performance is okay, but not exceptional.

The lawn needs at least 4-6 hours of sunlight before it's dry enough for proper mulching. I have quite a few trees, so that means no mowing before 3:00 pm.

Even under optimal conditions, I will see clippings on the lawn immediately after mowing. These disappear into the grass with an afternoon breeze or rain. They're typically gone by the following day.

The post made here are truly remarkable and explain why I got the clippins. I APPRECIATE THE COMMENTS VERY MUCH. THANK YOU AGAIN. I will wait for the grass to be dry dry. I will mow in the afternoon rather than morning (when it hasnot rained).
I did drive slow but I think that next time I mow, I will be ok even at the 3" high. If its too high I will do 4".
varmint you are correct: It is a kit (plastic.... as mentioned).
Of note: The dealer told me to remove the mulch plate aand mow to decrease the load on the mulcher. But I will wait for that option.
I will keep everyone posted. It should help someone else if they run into the same problem.

use full throttle because lower throttle reduces how much the mower can do and wont cut good (slows blade speed).