I planted Poa trivialis this fall in an area I have that gets very little sun, and has poor drainage. It has done very well, looks great, and tolerates the cold very well. My only concern is that it doesn't tolerate traffic very well, so using it for a campsite that sees a lot of use might not be an ideal application. Poa supina on the other hand does well with traffic, and from what I have read will become the dominant grass in a area that gets a lot of traffic that consists of other less tolerant species. Outside pride sells a mix of poa trivialis and poa supina for precisely this reason. It's a lot less expensive and over time the spreading nature of the supina will out compete the less hardy trivialis. Or you can buy them seperately and make your own mix.

dchall_san_antonio, Thanks very much for the advice. Yes irrigation is going to be a problem, especially since this lawn is not at my house and the person living there is elderly. I can make sure its watered well when I'm there but thats only a couple of times per week. Last time I tried to seed it I used the Scott;s "Sunny Blend" from Lowes but that might not be the best choice. Its also possible that it didnt get enough water to really become established, and last year was well above average here for heat with near-drought conditions. TYG

The advice you received was correct, despite the claims made by grass seed companies and their "shade mix" products: Grasses are definitely not going to do well with that little sun exposure. Mazus, Ajuga, and Green-and-Gold (Chrysogonum virginianum) come to mind as alternatives, but there are more options. Moisture will be the biggest concern as many shade groundcovers really cannot thrive if they are dry. There are some though, like barrenwort, that will do fine dry. Also, you need to specify how high you want the groundcover to be -- plants up to 1 ft. high are often considered groundcovers, but some people really prefer something that is only a few inches high. Personally, I really like U.S. native viola walteri var. 'Silver Gem' as a shade groundcover. Uploaded with ImageShack.us Click the link below, fill in your information about exposure, etc. and you will get some more choices. The conditions you list seem to leave you with many good possibilities. Good luck! Here is a link that might be useful: Groundcover Selector

Grass seedlings are tolerant of frost (even moderate freeze) conditions and it won't hurt them. They don't notice it, except that their body temperatures drop so low that they stop growing until the sun warms them again. You can throw a drop cloth over them if you really want to, but it's not necessary and you're likely to do more damage traipsing around and adjusting the cloth than you would if you just ignored it. One minor protection is to water moderately just before sunset. It carries the heat atop the soil down into it, and water requires an enormous loss of energy to freeze. The veil of higher humidity over the grass in windstill conditions (required for a first fall frost) will also protect them by reflecting infrared radiation back toward the soil, plus the fact that it needs to turn to dew before the dew point can drop below freezing. The dew itself then needs to freeze into frost, and there's more dew on a freshly-watered soil. That's a trick I use in the gardens to get myself an extra week or so out of them from the more durable plants. It won't work on those that object to near-freezing temperatures or a light frost (about 75% of my garden as I prefer tropical to extreme southern temperate plants for the most part), but grasses are unbelievably temperature tolerant.