Poor soil issues-HELP!

It could be tha your moss is just a result of damp and shade. If that is the sole problem, then spring and summer will eradicate the problem for you. If it is because your soil is boggy, adding drainage will help. You could put in 'french drains' if the problem is really bad: Dig a horizontal trench. One end of the trench will head in the direction of the spot where the water will be re-routed (if it doesn’t quite reach that spot, you’ll have to dig a connecting ditch down to it). Trench size will depend on your moisture problem.Small trenches are often dug to a width of 5”-6” and a depth of 8”-12”. Line the trench with landscape fabric, then fill with gravel. You want to preserve the porosity of the gravel, which promotes percolation of water through it.Wrap the ends of the landscape fabric over the top of the gravel layer. You now have a tube of landscape fabric filled with gravel. Shovel a layer of coarse sand over it and lay your turf on top. If the problem isn't that big, you can gradually add sharp stand to your soil to loosen it up. There are lots of different grass mixes. Just trot down to the garden centre and have a read on the back of the boxes. Some mixes are for a very fine lawn, others are for high traffic area (such as children playing football). Choose what is best for you. The main thing is to have your ground level, stone free, and throw out your seed. You could put on a light layer of soil and sand to keep the seed from blowing away. Keep it damp and keep off i for a couple of weeks and you will have a nice lawn for summer.

Is the moss growing on soil or on concrete? I ask because in the UK 'yard' implies a hard standing whearas 'garden' means in the ground and I think it might be different in the US. If my assumption is correct and you mean you have moss on the soil where you would prefer to have grass, you need to make conditions less good for the moss. Odds are its on compacted, waterlogged earth, so get in there with a fork and break it all up. Let the summer sun get at it, with teh trees out of the way the conditions may quickly sort themselves out but be prepared to dig and rake several times before deciding what to plant there.

Break out your roto-tiller and turn the soil several times. I don't know what grows well in your area so you might check with your local gardening shops and venues for ideas and advice. Personally, I would plant a combination of rye grass seed with another grass seed that has a fertilizer/weed control in it to get a thick lush lawn. I always scatter my grass seed right before a rain shower so the birds don't eat the seed or I use the sprinkler to water the seed in to the soil. Avoid over watering so you do not drown the seed. When mowing, do not cut it too short as the sun will burn it and turn it brown. Three to six months later, add another dosing of fertilizer/weed control. Within a year, you should have a beautiful lawn.