If rye is really what you have, you can use a product called revolver to help you transition back to bermuda. It is used during the spring transition by professionals to get the cool season turf to die off when the bermuda starts coming back. It is not, however, labeled for us over the top of st augustine. Don't give away trade secrets :>) I don't know about CO, but in TX only licensed professional can use Revolver. Otherwise homeowners have to use granular atrazene formulated for Saint Augustine lawns to do the trick.

Your location is not good news. I was hoping you were in Nevada sand but no. I (almost) never suggest that people get soil tests, but you absolutely need to get a soil test. You are in an area of natural mineral outbreaks which can sabotage your best gardening attempts. Boron, for example, is mined in your area. Too much boron in the soil will kill microbes, insects, microscopic insects, and even plants. Do you ever see insects in the grass? I would expect to see pill bugs, cockroaches, and earwigs. Maybe more of one than another, but at least some. You are fighting an uphill battle to grow fescue smack in the middle of the most hostile desert in the US. You might want to consider a different approach. Before you get a soil test, visit your county courthouse and ask for the agricultural extension agent. He'll office in the courthouse or very nearby. Ask him what seems to work best as far as turfgrass and soil amendments. He may know or may not. Keep an open mind for grasses like some of the buffalo grasses (UC Verde is a good variety in California) or some of the prairie grasses that thrive in your area. I realize nothing thrives without irrigation up there, but something must grow in the ditches. Chances are there are prairie grasses which, when irrigated monthly and mowed like a lawn, will look amazingly good and require very little care. When asking people about grasses, ask specifically about these: Big Galleta (Hilaria rigida) Indian Rice Grass (Oryzopsis hymenoides) Bush Muhly (Muhlenbergia porteri) Fluff Grass (Erioneuron pulchella) Red Brome (Bromus rubens) Desert Needle (Stipa speciosa) I am not familiar with any of these, so ask the people to talk to. You might Google them (look for Google Images). It is usually surprising to see what native grasses look like when seeded and mowed. Also visit the golf course and ask to speak to the grounds keeper. He can help you decide what to grow. He will be growing specialized grass for the course but he will also have a home lawn. Ask what he has. You originally asked about buying worms. My fear is that your soil's chemical and mineral make up will not let worms live in it. Only a soil test will tell. And the soil test you get must include micro nutrients, because the problem minerals you have show up only on the micro tests.

"mixed in with some green" "On the other side of my driveway, the strip of lawn that was most decimated by the grubs and reseeded last fall & this spring looks great." I bet you have grubs again. The inconsistency of the problem leads me to beleive that grubs are responsible for the damage. They like sunny, well watered locations near concrete (ie curbs, sidewalks, driveway) Do a grub test, pick up the soil and look under it for grubs. If you had grubs before (you mentioned it) then you probably have them this year too. Get some Milky Spore or some Bayer 24hrs Grub killer. Forget the ones that offer "control" or "season long" or "good for three months" you're past that point if you have grubs present in your soil/turf. The only other disease that resembles grub damage is Phytium Blight. Dog urine can some times have similar effects. I hope it helps.

You should be doing the first mow shortly and the second one a week after. If you didn't apply fertilizer at seeding you need to do so, they need to develop properly to survive summer. By day 60 after germination you should have mowed 4-5 times. Use a pre-emergent as described here in spring (since it's perennial, this will not affect already established goosegrass, see below for post control): http://lawniac.com/conquering-crabgrass-and-annual-weeds Use the method described here for post-emergent control( yes, I know it says Bermuda, same combo is used for goosegrass): http://lawniac.com/eliminating-bermuda-from-your-lawn Multiple treatments may be needed to achieve control. Avoid spraying fluazifop in hot weather, it will wipe out the fescue as well.