I live in the southeastern US, so I know absolutely nothing about your area, but I'm gonna go out on a limb here and say you are in sandy soil since you live in the desert? Lol! Therefore, your soil drains well...probably too well. You will need to keep watering during the winter to supplement the rainfall that you do get. When to water? I go by visual appearance. When the grass blades start to turn a bluish color, you should have already watered. Some people say that its time to water when they can see their footprints in the grass behind them as they walk. Also, another way to tell if you need to water is to check your soil. Take a pocket knife, or any knife, and cut down about 2 inches and pull out some soil (sand?). If the soil is dry, then its definitely time to water. Your soil should be able to hold together between your fingers to some extent if it has any moisture in it. When you do water, water deep and infrequently...OMG! He's in the desert!!! I suppose you could water one spot 24/7 for 52 consecutive weeks and it never would puddle!!!!! Well, just water until the reservoir is dry!!!

Ok, I'm sorry. Getting carried away here. Seriously, watering deep and infrequently is the best advice I can give you about how to water. After you think you have watered an area long enough (maybe 15-20 minutes?), pull out that knife and cut down into the soil about 2 inches down and see if there is moisture at that depth. Again, if you pull up some soil with your fingers, see if the soil holds together with moisture. If it does, you probably have applied enough water.

Yes, you do need to water in the winter to supplement the rainfall you get; not only for the turf requirement from the soil, but also because of winter dessication from low humidity and high winds that dry out the grass blades. Also, get a rain gauge if you don't already have one. Your tall fescue should be getting about 1 inch of water per week. I'm sure you'll get some other great advice from this forum.

Actually, we are mostly rock hard clay where I'm at. But I amended the soil with roughly 30% compost, so it's not as rock hard anymore. I have been following the deep/infrequent waterings. I just wasn't sure if I'd have to continue watering in the winter, when it's freezing overnight. I was afraid that maybe the freezing could cause damage?

So if I continue to water, then the grass shouldn't go dormant right? Will everything die, or will it just go dormant if I don't water? Thanks.

Well, damn. How can you be in the desert if you're not in the sand? Where did they take the sand? And if there isn't any sand, is it really a desert? I'm confused. Marge, get me a pain pill.

Ok, so let me re-load on this one. Forget everything I said in the previous post, except for watering deep and infrequently...that still applies. Since you don't have sand, but do have clay/compost, your soil will retain moisture more easily. Apply water when you see signs of stress (wilt or dessication) on the turf. Remember, we water our turf as a supplement to rainfall. I doubt that everything will die if you don't water this time of year. You may already know this, but I'll say it anyway. When your grass is covered with frost, or the air temperatures are below 32 degrees early in the morning, please don't walk on your grass. Let the sun get up high enough in the sky to melt the frost first before you walk on it. I can't tell you how many times I've had to tell golfers to stay off the frost covered grass until it thaws. And if an explanation is needed, I may defer to one of the other fellows who post advice on this forum. Ok, I'm gonna go lay down now. I have to figure out why there isn't any sand in the desert.

The Mohave Desert is what we used to call the "High Desert." Altitude is about 3,000 feet. It is not unusual to see snow in the Mohave. The key characteristic of the Mohave is the Joshua Tree. Please don't be afraid of telling us where you really live. If you live anywhere near Boron, CA, you might not be able to grow anything.

You'll need to do some soil tests to determine what kind of soil you have. The easiest one is the jar test. Do a search for it or go over to the Organic Lawn forum and look for some posts by kimmsr. It is very possible to have nearly pure sand but with the slight addition of a few minerals, it would seem like concrete or clay. Do the jar test and then do a real soil test. You might be able to correct your micronutrients and convert your soil into something that will really work much better.

If you have bermuda now, you will soon have a 100% bermuda lawn. The fescue will die little by little and the bermuda will be there to fill in. Bermuda does not have to be cared for when dormant. However, your soil does. Another characteristic of your area is extreme dry air and severe heat in the summer. Keeping fescue looking great under those conditions will be a challenge.

Search the Internet for a title called The Bermuda Bible. The author, texasweed, posts it on this forum every now and then. He has it permanently posted in other forums and websites. The BB will give you excellent advice for general care. Your soil and climate are not specifically covered in the BB but you will be better off.

One thing you can do to help yourself is to use organic fertilizer at least once a year. I use ordinary corn meal as a fertilizer. It would work for you, too, but it is sometimes hard to find. If so then alfalfa pellets always seem to be available.

I'm pretty darn sure it's mostly clay (except for the truckload of compost I amended it with last spring). I still need to try out the jar test, I've seen that posted on here before.

I live 30 minutes west of Boron, and we get snow maybe once or twice a year. I can grow plenty of stuff just fine, I just have to add pleny of compost, almost half compost. The fescue did fine with the summer heat, just had to water it plenty, and fertilize in spring and fall. It never really died in the heat (I was amazed too).

You said my soil needs to be cared for in the winter, what do I do to care for it? Do I continue to water probably once a week if there's no rain? I already aerated with 4" core aerator about 2 months ago. Thanks.

Yes, watering is what I had in mind. Water for an hour, all at once, at least monthly. Mulch is excellent for the winter because it helps keep the moisture in the ground. Use as much as you can afford. For non turf areas you can start at 2 inches. If you can find mulch made from local pest plants, use that. Around Texas we use mulch made from "cedar." It is really a pesky, aromatic, juniper plant that grows like a weed in the Texas Hill Country. If I remember right you have a similar juniper on the escarpment down to the LA Basin. Starting at Big Bear then west across the ridge to LA, it was everywhere. But maybe nobody is chipping them. Around here the ranchers do it to free up the water.

I grew up in Riverside and visited Apple Valley about twice a year in the '60s, so I am somewhat familiar with your situation. Climate is similar but perhaps not the soil. You're too close to Boron for comfort. Look at your town on the Satellite view of Google Maps. It's not a pretty sight.

I usually wait until all attempts are exhausted before suggesting soil testing, but in your case I really suggest you get a soil test and report it here. Search in this forum for a guy called Andy and a guy called MorpheusPA. They are very helpful in reading soil tests for people. They'll have some suggestions as to where to get it tested. They both likes the University of Massachusetts and Andy likes another one in Mass. Those tests, at $13, are pretty inexpensive compared to most of the rest of the soil tests I've seen. They can read the soil test, tell you where to get the micronutrients you need, and how to apply them.

I sympathize with your interpretation of the soil as being clay. Humor me and prove it to yourself with the jar test. A little bit of magnesium can gum up sand and make it act like clay. That California high desert has some crazy soil...as evidenced by the mines at Boron.

Phoenix is clay. Are we not a desert?

Phoenix is desert. Did someone say something that seemed to contradict that?

Warning: Sciency stuff to follow
Deserts are defined by the amount of precipitation falling annually. Soil type has nothing to do with it. Even though the Mohave is relatively close to the ocean, the sea breezes have to climb a high escarpment before reaching the Mohave. (from the Los Angeles basin that escarpment is so high and rugged it is referred to as mountains). As the moist, sea air climbs it cools and drops all the precip on the side of the escarpment. By the time it reaches the top it has no moisture left to fall out.

Phoenix receives the Pacific sea breezes after flowing several hundred miles. Those breezes lost all their moisture in the area from Redlands to Hemet, California. The air flows up, loses its moisture, then flows down over the real mountains. As the air flows down the mountain it heats up so Palm Springs is much hotter than the air on the ocean side of the mountains. The air continues to flow east and actually picks up moisture from the irrigated areas of the desert. By the time it reaches the Colorado River, it often has reasonable amounts of moisture. That is why you see the vegetation change from Calif to AZ when you cross the river. It is still desert, though. It is desert all the way to San Antonio in the south and to Dallas in the north. At that point and to the east there is a strong humidity influence from the Gulf of Mexico sea breezes.