Question
Recently my wife and I took over her Grandmothers home.  There's a full front and back yard which has been cut regularly, however, we've not been able to get rid of the moss in some sections with seeding and lime.  Short of ripping it out and starting over is there anyway to force it out gradually by grass seeding?  One other thing I've noticed in these same area's of the yard the moss is growing out of control is a stong smell similar to Cat litter.  The kitty litter smell was there from the beginning.  any suggestions on what the smell could be or how to be rid of it?
Best Regards,
Ed

Answer
Good Morning Ed:

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Moss invading lawns is a common problem. Moss thriving in lawns signals that grass is weak and has thinned for some reason, allowing the moss to take over. There are many potential causes, including excessive shade, compacted soils, poorly drained soils, low soil fertility, high or low soil pH, and poor air circulation. Poor lawn care practices are another source of moss problems. General lack of care, including irregular mowing and little or no fertilizer applications are common problems leading to poor turf growth.
Adding limestone is a common "remedy" mentioned for moss control, but is not suggested unless a soil test has shown the pH needs to be raised. Many soils have a high pH, adding limestone will make this pH go even higher, adding to the lawn's problem. Ferrous ammonium sulfate or ferric sulfate (iron sulfate) can be used to control moss to some extent. The moss will temporarily burn away, but tends to return fairly quickly. Raking out moss is another option; usually followed by reseeding.
Modifying site conditions to favor lawn grasses and discourage moss is a suggested way to manage the problem. Too much shade for acceptable grass growth is a common underlying cause for moss invasion. Pruning trees and shrubs to improve air circulation and light penetration is a good starting point. I can imagine that your wife's grandmother has many trees and or shrubs in her property. Evaluate the site to make sure the proper grass for the conditions is being used. For shaded areas Red Fescue would be a good consideration.
Take a good look at the soil conditions. A soil test can be helpful, as it could be the soil pH is out of line, contributing to the problem. Reduce soil compaction by core aerifying. This may also help correct drainage problems; although serious drainage problems may require more extensive work to correct.
Evaluate lawn care procedures, especially fertilizing. Lawns need adequate fertilization, in particular nitrogen. Established lawns in shady areas need less nitrogen than in full sun. About 1 to 2 pounds of actual nitrogen per 1,000 square feet per season is all that is needed in shade, compared to 2 to 4 pounds in full sun. Too much nitrogen could be one of the reasons you are experiencing the strong kitty litter odor.  
Also be sure additional lawn care practices are sound. Excessively short mowing may be a source of the moss problem; a range of 2 ?to 3 inches is ideal for most lawn grasses. Mow on a regular basis (based on rate of lawn growth) to avoid removing more than one-third of the leaf blade. Also avoid excessive watering, as this may also contribute to moss problems. Water deeply and as infrequently as possible, based on lawn needs.
You did not tell me your location but I will assume it would be in the cool season grass belt area. It would be too late to start lawn renovation at this time but I would strongly suggest that you begin pruning the trees and shrubs to open up the lawn to more sunshine next year. Rake off as much moss as possible and start next year by mowing at the minimum 2 ?inch height. Hold back on all nitrogen until your grass becomes better established. Get a soil test through your local Cooperative Extension so that you know exactly what your soil is lacking.
I hope I have helped you
Have a good lawn!
Floyd McMahon