When you water it, what is your schedule? How often and how long do you water?
When were the last two times you fertilized and what did you use?
Is your soil high in calcium?

I haven't watered since it's been raining. In summer, I water every day. I fertilize with coffee grounds and some compost. I don't know if the soil is rich in calcium.

What type of fertilization do you recommend? When should I apply?

Go to your fave garden center and ask for a st Augustine formulation, if not avail, any all purpose fertilizer will do. Here in the States I think we fertilize 2-3 times a year and many people use organic or non organic pre-emergents to reduce amount of weeds that will inevitably grow thru the grass. If no pre-emergent product available, fertilization will go a long way as St. Augustine grass tends to choke out whatever grows in its path.

Algo google st Augustine grass care and go with SIMPLEST routine. Some people tend to go overboard with lawn care and frankly , don't think it has to be that hard, plus it can get pricey.

Here's how you take care of St Aug. You're not going to agree, but I assure you, it works.

<b>Watering</b>

Water deeply and infrequently. Deeply means 2.5 to 3 cm every time you water. You're going to have to figure out for yourself how your watering system applies water. Here in the states we use cat food or tuna cans. They are about 3cm high. We put several out on the lawn, turn on the sprinkler, and check the time. Come back in 20 minutes to see if the cans are full. Likely they will NOT be. Keep checking back until they are filled. The time it took to fill your cans is the time you will always water in the future. Infrequently means no more than once per week when the temps are higher than 30C. NO MORE OFTEN THAN THAT. If you have a full week higher than 35C, then you can go to once very 5 days. The only way this works is when you water deeply. With temps between 25 and 30C, you should only water once every 2 weeks. Between 20 and 25C you can back off to once every 3 weeks. Below 20C and you should still water once per month. If you get rain, then you should watch the grass for signs of wilting before you water again. The point of watering like this is to allow the soil surface to completely dry out before you water again. Most weed seeds must have continual moisture to germinate. When the soil surface dries out all the time, the weeds cannot get started. There are other benefits to deep watering, but this should do for now.

<b>Mowing</b>

Mow St Aug at your mower's highest setting. In fact have your adjuster welded into position so you can never change it. There is never any reason to mow St Aug lower than the highest position. Tall St Aug further helps to keep weeds out, because any weed seeds which do germinate must have sunlight to get started. The wide blades of St Aug grass do not allow enough light down to the soil where the weed seeds are trying to get started. I have a yard that I keep "mowed" down to 30 cm. Yes, 30 cm. I have to use a string trimmer to do that, but the grass seems to love being that tall. I have another yard where I let it grow up to 70 cm. It grows find and looks amazing flowing in the breeze.

<b>Fertilizing</b>

Since you are already fertilizing with organics, I suggest you pick up the pace. Unless you have a continual supply of kilos of coffee grounds, you should buy something like alfalfa pellets (Rabbit Chow, Fish Chow, Chinchilla Chow, or whatever is cheap at your local feed store). Coffee grounds are fine but they are low quality (low protein value). Alfalfa has about double the effectiveness of coffee grounds. A good application rate for coffee grounds would be 11 to 15 kilos per 100 square meters. But a good application rate for alfalfa pellets would be more like 5-10 kilos per 100. With organics you can fertilizer any day of the year, or every day of the year without fear of hurting anything. As for timing your fertilizer I suggest once in late winter (about a month before the date of your average last frost), once again in late May, again in mid July, again in early September, and again in late November. If you have national holidays the come close to those times, then use those holidays to remember the timing.

If you follow these guidelines your grass will take over almost all the grassy weeds. There are some broadleaf weeds which will shade out St Aug so those will have to be either pulled or sprayed. I believe you don't have access to the really effective sprays we can still use on this side of the pond. Pulling will be your best bet.

Here's a picture of 70cm tall St Augustine.

The grass above is on the edge of the Texas desert and had not had any water for the previous six months. It also grows in 100% shade under a dense live oak tree and with my house as a block for the afternoon sun.

The following picture shows the effectiveness of alfalfa pellets.

The picture was posted to GW by mrmumbles in 2010. The grass is zoysia. He applied the alfalfa pellets in mid May and took the picture in mid June a month later. You can clearly see the improved color, density, and growth.

Hope this helps.

Thanks for your help! Should I scarify the dead/yellow leaves first? And then fertilize?

Yes

The lawn is just coming out of winter. Normally all sins are forgiven over the winter. It should green up regardless of whether you do anything to it. But it will help the soil if you apply organics about now. No need for anything else.

Since spring is a month from now, I will scarify and fertilize next week.

Yes, I mean "de thatching" or raking.

Dethatching is something you never want to do with St Augustine. Since St Aug spreads by sending stolons (runners) out over top of the soil, when you dethatch you break those stolons and essentially dig up the entire plant. The only time you need to rake St Aug is with a leaf rake to remove debris that might be shading the stolons. If you have large leafed trees overhead, you can usually mulch mow those into little bits small enough to fall down to the soil. If you have live oaks with 1-inch (2.5cm) leaves, then you have to rake them up and off the lawn. I rake mine into the flower beds.

Thank you dchall_san_antonio. I will rake carefully the lawn to remove debris and the dead leafs from the frost.

I have had St. Augustine for decades. It's a warm weather ground cover. During the short, cool days of winter, it looses it's color, and stops growing. In the warm/hot months, it turns green, and becomes so thick, that it is hard to push the mover through it. I just look at the winter months as a welcome break from mowing :-)