It could be any number of things, but I think you should do two soil tests. One using only soil from the areas where the grass is yellow and one test from areas where your grass looks nice and green. If the two tests are the same or almost the same then you will have eliminated many possible causes. Also I think more info is needed. How long has this been happening? Has the yellow been getting more prevalent through the years? What kind of grass do you have? Have you done any seeding yourself? Do you fertilize? When and how often? Some pics would also be helpful too.

Marcj117 is there anything at all that you like about the rocks? Do you know what is underneath the rocks? I want to encourage you to at least remove some near the front of your house, but it will be time consuming and tedious. It took me around three days to move rock from one side of the yard to the other side of the yard (luckily it is not my yard). It was a small amount of rocks. Around twenty years ago my neighbor decided to have a river rock yard with just a small area of grass. She also had a wonderful Cedar tree close to my property line. It all looked hideous so I won't go on about that. I wasn't watching the calendar so I do not know how many months passed before the weeds arrived. They just sprout above the plastic. She was long gone by then. The house has changed owners a few times since then. My current neighbor does not weed weekly. About every three months she and her family clean the area. It is not the weeds that are so messy, it is needles from the tree. The needles get stuck in the gaps between rocks. On my side under the tree there is an area too shady for most plants to grow. I keep it as an unplanted area. I rarely get weeds because I leave the needles on the ground. I am very grateful for the free mulch.

Adrienne in Thousand Oaks: Regarding UC Verde Buffalo Grass, we installed it June 2021 so can attest to how it took watering twice a day to establish, then less frequently until we were watering twice a week with good results; I live in Thousand Oaks and were restricted to watering once a week for 15 minutes which was a good soak and it survived the limited watering last summer. When first planted as plugs we had a lot of weeds but it eventually filled in and is very thick. What we don't like is that is it dormant and brown in color from November to March; it has been slowly turning green in the last few weeks now that it is spring. It requires very little mowing, about once a month at most from spring to fall. The only way to buy it in Southern California is from FloraSource Ltd. They ship it as plugs in flats so it is labor intensive to have it installed; cost is twice that of sod.

These are the five I think of using. Except for the “tracks” they seem really easy, but at least the first letters of the answers spell a real word unscrambled. If you have a harder one with the same first letter, I would gladly exchange. Not very inspired solution word either. Seems my brain is a bit scrambled, too. I have two legs, but they only touch the ground while I’m at rest. White bird featherless, flying down from Paradise. Flying over sea and land, now lies dying in my hand. You can see me in the water, but I never get wet. Many of them come down to the river, but none ever drinks. What goes up but never ever comes down?