Cause and treatment of lawn grasses death
Large sections of several home lawns within our development are dying, leaving weeds and crabgrass, which have also now died. How do we determine the cause and how do we get a lawn back? The lawn service has tried aeration, reseeding and standard fertilization, and I have spread limestone to eliminate mosses. Help?
Your lawn company should have done a soil test and be liming according to the results. Unless liming is based on a test, it may not achieve anywhere near the correct pH. (Search 'soil testing' on our website for how to do it and a list of labs.)
Many lawns had fungal disease this year because of the extremely wet weather. Fertilizing should never be done in early spring--it can cause fungal issues.
Fall is the primary time to fertilize (a light fertilization is ok for new or struggling lawns in mid-May).
You still (barely) have time to renovate your lawn--aerate and overseed. Read through this fact sheet for other ideas on what practices you might want to do or change: http://extension.umd.edu/sites/extension.umd.edu/files/_docs/programs/hgic/HGIC_Pubs/lawn_pubs/HG102...
Moss does not harm lawns. It simply grows where conditions are favorable to it, and the grass has thinned out for other reasons. This explains why you have moss: http://extension.umd.edu/sites/extension.umd.edu/files/_docs/programs/hgic/HGIC_Pubs/lawn_pubs/HG100... and what to do.
Moss can also be a nice groundcover, if you have areas where it's too shady for grass.