I have a lawn with multiple personalities. It is half full sun and half full shade all season long, on a mildly sloping lot in Portland, OR, and I'm having a hard time keeping both aspects of my lawn happy. The full sun areas tend to get dry and burn in the summer heat (photo). The full shade areas look great in the summer, but turn into soggy patches full of moss (and even mushrooms - photo) in the early fall and winter. By October the whole thing is pretty lush and green (photo). My current routine is as follows: aerate and dethatch in March/April. Then overseed and topdress the entire lawn using 50lb of a 3-way Rye mix from a good local distributor, 50lb of starter fertilizer (12-8-6) and 50lb of lime. Apply nitrogen-based fertilizer using the "4 holidays" rule in May, June, September, and November. Mow to 3" weekly. Aim for 2/10" of water per watering session. I'm basically doing everything I'm supposed to be doing, but the moss returns, and has crowded out all the grass in the full shade/moist areas of the lawn by by the time it starts to grow again, and overwatering the dry and brown spots just makes the soggy mossy parts worse. My questions: Should I treat these two very different parts of my lawn simply as separate lawns? Should I seed the full shade portions with different grass that would prevent moss by thriving during the wet and winter months? Will aeration and regular dethatching of the whole lawn eventually get rid of the worst of these problems? Should I aggressively aerate/dethatch certain areas as opposed to others? Should add sand or Turface to improve the permeability of soggy parts after aeration? What else can I do? Thanks!