...........also, all of the above are available a Home depot. Triple 15 is only available in 50 lb bags, but they carry 16-16-16 in a much smaller bag . The slight difference in numbers is not a problem.

Thanks a lot Tom. I will buy the 16-16-16 fertilizer. Do you think adding fescue seeds in areas that have lean grass will help?

Before you do any of that, are you in the Big Bear Lake part of SoCal or the Indio part of SoCal? SoCal has every growing zone, so you cannot take a stock answer and run with it.

Marathon is a northern grass that is heavily marketed in the west for decades; however, it is only appropriate in a very narrow strip within a mile or two of the beach and the SoCal mountains above 3,000 feet. So where do you live in SoCal? Don't be afraid to name the town, we won't come visit you...unless you live in La Jolla ;-)

Another thing about adding more topsoil. Every time you do that you change the drainage on your lawn. I've seen lawns where the owner wanted to fix a "low spot," without realizing that low spot was the only way the back yard drained to the curb. They created a dam that flooded their back yard creating a swamp that would not grow normal grass. In other cases I've seen yards that received 1/4" of topsoil every fall...for 40 years. They have a mess. They have had to build little retaining walls to hold back the soil to keep it from melting onto the sidewalk. Then it's a big mound inside the retainers. So my advice is to NEVER add topsoil UNLESS you have a low spot that continually pools water. Then you should carefully raise the low spot until it no longer pools but drains toward the curb.

Thanks :) I live in Poway, near San Diego.

Getting back to your very first question, it is normal for a lawn to stop growing and go dormant at certain times of the year. I would not be concerned at all with your lawn because of that.

I would be concerned about it because Poway is too warm for Marathon. It can grow with enough water, but with California in the drought conditions, it's a little irresponsible to water it that much. What is your watering schedule? How often and for how long do you water? If you are watering more frequently than once a month at this time of year, that is too much. If you water more frequently than once a week in the hottest heat of summer, then that is too much. The warm season grasses (bermuda, St Augustine, some zoysias, and a few others) will thrive with 1 inch of water, all at one time, weekly in the heat of summer. I will tag on the 'normal' watering that should work for grasses which are adapted to their climate. Marathon is considered a northern type grass, so not good for inland SoCal. Even west of Interstate 5 in your area is iffy. You have those 300 foot tall cliffs on the beach which mess up the normal seaside micro climate. If you lived in an area that got fog every morning until 11am, then you could probably do well with Marathon.

There is a small park and swimming pool at the end of Sycamore Tree Lane in Poway. You might visit that park to see what grass they are growing. I'm going to guess it is a warm season grass like bermuda, St Augustine, or a warm weather zoysia. That grass is doing too well in the shade to be bermuda and not coarse enough to be St Augustine. I'm going with zoysia, but I suppose it could be Marathon. No matter what it is, you should find out what it is and how they care for it. Of most importance is their watering frequency and amount.

You should not need fertilizer until after spring. May is a good month for the first fertilizer of spring. Next fertilizer would be around Labor Day in September. Final fertilizer would be about a week after the grass completely stops growing. In the mean time you can worry about weeds. If you have plants that flower in the early spring, watch for those to bloom and immediately apply a preemergent herbicide. Then in April you can spot spray broadleaf weeds with a herbicide like Weed-b-Gon.

Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the daytime air temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall.

Thank you very much for taking the time to explain in detail. Really appreciate it.