We have taken out all of the grass in our small back yard. There was not much top soil covering the clay underneath. We will dig out some of the clay and put in top soil. We have automatic sprinklers.
What is the best grass for our area and soil? Should we use sod or seed?
When is the best time to put down the new grass?
Any other information would be greatly appreciated. Thank you.
Your timing is excellent - the first two weeks of September are ideal for new lawn establishment, particularly if you plan to seed the lawn. Sod is much more forgiving in terms of timing but regardless, early fall is best.
You likely don't need to remove the natural clay soil to get a good lawn. Properly prepared and maintained, the clays in our area are very productive soils with good fertility and clay holds water better that other soils. And do avoid adding top soil that is significantly different than the clay. Plant roots generally have trouble crossing boundaries between very different soil types. I live in east Medford with Carney clay (commonly called black sticky) and have no trouble with the lawn. The biggest problem with clay is that its permeability is low so run off can be a problem. That can be solved by watering for short periods of time several times. For example, I run my sprinkler for 10 minutes to wet the soil, then an hour later, run it again for 20 minutes, and then later for another 20 minutes. That schedule is followed twice a week and avoids run-off while soaking several inches into the soil.
Whether you seed or sod is up to you - both can result in excellent lawns. Sod is of course quicker initially, but seeding is less expensive and there is a much larger variety of seed mixes available. The most broadly used mixes in our area are mixtures of fine fescue and perennial ryegrass. If the area is primarily in full sun, look for a mixture with about 70% perennial rye. If it has a fair amount of shade, then go with a mixture that has more fine fescue, up to 70%.
Two OSU Extension publications will give you excellent information on establishing and maintaining a lawn. they are:
EC 1550 Practical Lawn Establishment and Renovation at http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/19278/ec1550.pdf and EC 1521-E Practical Lawn Care for Western Oregon at https://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/51127/ec1521.pdf.
You can find these and more at our online publications catalog here (http://extension.oregonstate.edu/catalog/) and enter lawn into the search box.