Question
1-1/2 acres; 40 yrs mulching riding mower; increased grass growth this year due to wet spring and summer and increased fertilization. Yard has never looked better. Problem: mower leaves trail of mulched grass everywhere. Most times I have to remow two or three times. My mower Toro LX420 42in deck doesn't stuggle with grass - just leaves the trails. Should I: invest in new mower; find a better universal mulcher (this is my second mulcher w/the Toro - was only average from the beginning) or just be content with mowing 2-3 times? Thanks in advance for any help.

Answer
Okay; here are a few principles.
No more than one third of the grass blade should be removed at any one time. So if you are maintaining the turf at four inches height, then it should not be allowed to get taller than six inches . I would not be surprised if, under the growing conditions you describe, the turf has to be mowed every five days or so.
A mower mulches by cutting up the clippings many times. This is achieved by 'deck design' - and "Toro" has a good reputation in this regard. The clippings are held in the "dome" of the deck long enough for the blade(s) to pulverize them into smaller bits and pieces which fall back on the lawn and decompose. There are "baffles" under the deck to aid the even distribution of the pulverized clippings across the mowed strip. If these structures are damaged there might be clumping
Finally there is the moisture condition at the time of mowing. If the turf is wet, the clippings will not 'flow' and clumps will be the result.
I do not know that I have answered your concerns adequately. If you have further questions, do not hesitate to follow up.
We will lick this problem yet.