Oh, final thought: I am suspecting the front lawn is a different season than the back, since they behave very differently, but I guess that could be from the shade profile of the houses as well. The back lawn was installed after the front lawn, front was done in November, I think, then the backyard was done by the previous owner the next Spring.

Hmmmm. You have a lot going on.

How have you been watering? How long and how often?

Mowing probably has not been a concern because the grass is not growing. Once the grass gets growing, raise your mower to a level from 3 inches (Kentucky bluegrass) to all the way to the highest (fescue). It looks like you might have some KBG in there, but KBG and fescue look much alike. I would expect you to have a rye grass only because you are in the PNW...sort of.

On to fertilizer. Since you live in Oregon you must be a tree hugger or a redneck (I've met both from OR). This is good because I am going to suggest the fastest way to improve your soil, regardless of how bad it is, is to pound it with organic fertilizers. I am assuming your gravelish soil actually has 'dirt' in it. If it is really just rocky, then replace it. But I'm going to suggest fixing what you have. Go to the GardenWeb Organic Gardening Forum, find the FAQ, and read the last one on lawn care. The gist of it is you can find inexpensive organic lawn food at your local feed store. Back when I wrote that FAQ, corn was dirt cheap. This year it is the most expensive material out there. I have switched to rabbit food (alfalfa pellets) this year. A 50-pound bag should cost about $12. For you the application rate can be up to 50 pounds per 1,000 square feet. That is a TON of fertilizer. To start off I would go with 20 pounds per 1,000. Put that out and wait 3 full weeks to apply again. Apply the second time at 3-4 weeks and at a rate of 30 pounds per 1,000. Wait another month and apply at 40 pounds per 1,000. If you start that now, you should know after the 4th of July if it is working. At the minimum you should see dark greening of the grass you have. What you should look for is the return of grass in the thin areas. If you don't see that, then at the end of summer you will need to reseed. I would continue with the monthly fertilizer until the grass stops growing in the fall.

Organic fertilizer is the fastest way to improve the soil because you can apply it with no fear of hurting the grass. Chemical fertilizers are salty and can burn the grass in the summer.

You also need to learn more about your watering system. Put out cat food or tuna cans and time how long it takes to fill them up. That time is your starting point for weekly watering. You should be able to water once a week in the summer and get the job done for the rest of the week. If the grass wilts before a full week is up, then water immediately but water for a longer time than it took the first time. If you get runoff, stop immediately and let the water soak in for 30 minutes. Then start watering again until you get the full amount of time. With my watering system and pressure, it takes me 8 hours to get an inch of water. Your system may only take 45 minutes. Every yard is different.

One more thing you can do is a soil structure test. Find a glass jar with straight sides. Fill it half full with soil. Then fill it all the way with water and a drop or two of dish soap or shampoo. Seriously, only a drop - not a squirt. Shake up the jar and let it settle. After 2 minutes measure with a ruler (and camera) how much of the contents has settled. Then measure again after 2 hours and again after 2 days. Note also how cloudy the water is at the times. Sand and rubble will settle immediately. Clay will never settle and will cloud the water after 2 days. Everything else in between is silt. Post the pictures to your Picasa site.

For now I'm not worried about how bumpy your lawn is. Leveling is your second priority behind greening. The water and fertilizer suggestions above will definitely green it up. As the soil improves, the surface characteristics may change. It may not improve but it might.

Spot spray the black medic and clover with something like Weed-B-Gone for clover. By spot spraying you are minimizing the collateral damage from chemicals.

Gnats are not a lawn problem that I'm aware of. You will find that when you are on a full organic feeding program, you will see more lizards, toads, birds, and other critters that take care of pests for you. I've always had little white flying things in my lawn. I notice it when I mow, but then again I don't get down and roll around...much.

One more thing you can try to improve water penetration: mix baby shampoo and molasses in a hose end sprayer (I like the Ortho) at a ratio of about 50/50. I just eyeball it in the jar. Take the screen off the down tube on the sprayer and spray it on the lawn. Adjust the dial so you see brown foam coming out. Spray it right before you water the lawn. The soap and molasses each help to 'wet' the water and reduce the surface tension. This will let the water penetrate deeper. You can repeat every time you water or skip to every other watering. At the end of two months you should have softer soil after watering.

Thanks for the info! I'll have to read through that a couple of times. I'm not clueless (as my original post may indicate), I understand the science, but I am new to the lawn game. The lawn is growing, but maybe not evenly or healthily, and maybe not much at all in the front. I'll try the liquid aeration thing, too.

And, no, I'm not a tree hugger or a redneck. I'm in Bend, so more of a hipster influence. :) I'm not militant about going organic, but I do enjoy doing things naturally just because it's usually more effective and responsible.