Question
We have low areas in our lawn & places where the grass won't grow beacuse of the lack of good soil.  Would it be best to add topsoil now (November) or wait until spring?  We will be adding it to some areas that already have grass.
Thanks-  

Answer
Hi Debbie, The most important thing to remember when adding soil is to avoid "layers" of different textured soil.  A loose layer on top of a harder layer will hold water during wet times making root rot or fungus a real possibility.  It also dries quicker, so during drought or winter cold, the grass may be damaged also.  Your best option is to use the same type topsoil you have now, incorporate some organic matter (leaves, grass clippings or compost) and till the new soil into your existing soil to form a uniform soil mix about 6" deep.
When you add soil doesn't really matter if you sow some type of grass on it immediately to prevent erosion.  If it's not time where you live to sow the grass you desire, then sow annual ryegrass to hold the soil.  It will die out next spring and not be a weed in your new lawn.
Some grasses will not survive being covered with soil, some will. But I'd till the existing grass in anyway.  It will just add organic matter to your soil.   Jim