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Last summer, in the fierce summer heat, we lost chunks of our St. Augustine lawn. In the past, the spring rains just spurred regrowth that filled in the dead patches. But this year we've had a serious drought. The patches of dead grass aren't going away.

I'm wondering if I should be clearing out the dead vines in those patches, which are at least half an inch thick in places, to better allow new growth to spread and root directly in the soil. What I have is what up north one would call "thatch". Down here we never worry about thatch, because the dead grass just self-composts. But not this year.

So, for those of you who are familiar with St. Augustine and Central Texas heat ... clear or not to clear? Clearing those vines is not a huge amount of work, actually. The dead vines pull away pretty easily. BTW, the lawn is vigorous everywhere else.

Comments (19)

  • botanicalbill
    12 years ago

    I would not clear the dead grass for two reasons, you may spur weed growth by exposing soil and you will dry out the soil quicker. The dead grass is acting as moisture insulation.
    Once you see it filling in, you may want to clear some dead grass then.

  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    Original Author
    12 years ago

    Well, my rationale for clearing out the layered dead grass is that the way St. Augustine spreads is with vines that root as they lengthen. If the St. Augustine vines are expanding on top of a thick layer of dead grass, it isn't obvious that they'll be able to root properly as they lengthen. Also, St. Augustine is VERY intolerant of shade, so it's hard to believe that the layer of dead grass is going to help when new vines try to emerge from below.

    I have no trouble keeping the areas moist.

    Now, I'm assuming that the problem wasn't Cinch bugs. Was never any evidence for them, and after this cold winter, I'm pretty sure they're gone.

  • dchall_san_antonio
    12 years ago

    daninthedirt, if you think StAug is intolerant of shade, you have not tried the alternatives. St Aug is the ONLY grass that will grow in the shade down here. My front is 90% shade from three, 60-year-old live oak trees. It is looking great this year.

    You will never have St Aug in your dead zone unless and until you decide to water it. I'd like to help you but you have to agree to help yourself first. It did not die from the heat. It died because you did not water it...during the heat. All it needs is to be watered once a week during the heat. Once a week is dependent on your situation (rainfall, sprinkler ability to put out water, soil type, soil structure, soil depth, grass type, density, grass mowing height, wind, temperature, humidity, direct sunlight/shade, cloud cover, and probably something else). You do not need to keep it moist. Moist is what weed seeds need. Established grass only needs infrequent watering. We probably have similar soil. I water once a week for 3-5 hours per zone. The time is because my watering system only applies 1/8 inch per hour over 900 square feet. So I apply 3/8 to 5/8 per week depending on how humid it is or isn't. If you have full sun, you might need to apply a full inch per week.

    I don't think it will make much difference if you remove the old chaff. A really good tool would be the vertical rake, power rake, or slit seeder. These are essentially the same tool. Go no deeper than 1/2 inch with it. Follow up with a leaf blower to get rid of the loose stuff this tool creates. The digging will expose minimal weed seeds to the sun and moisture.

  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    Original Author
    12 years ago

    Actually, that's right. St. Aug is more shade tolerant than, say, Bermuda. But it still doesn't like shade. Zoyosia might do better than St. Aug at shade tolerance. I'm also under oaks. About 50%.

    I'm not sure why you're offering to help me water my grass. I never said I didn't water it. I do. I was just making the point that the drought has increased water stress on it. And yes, those patches died because they didn't get enough water during the fierce heat last year. I think.

    My reasoning in keeping the bare areas from drying out completely on the surface is that St. Augustine largely spreads as surface runners. It would seem that those runners would be reluctant to root in completely dry soil. But, yes, one has to fight weeds if one does that.

    I'll probably remove the dead vines in half the area with a rake, and see what happens there.

  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    Original Author
    12 years ago

    Covering it with a loose landscape mix might be a good strategy. Thanks. That way, the cover is very permeable (unlike the dead, dried runners, which I would remove), but it will keep the soil somewhat moist underneath.

  • dchall_san_antonio
    12 years ago

    I offer to help you with watering because I'm just that kind of helpful guy. When grass dies from heat, the problem is water. You did not ask for watering advice but it was clear that you were either unwilling to water or were not aware how it impacted. Proper watering is key to St Augustine survival.

    St Aug will send runners in all directions. You are correct that it will not root in dry soil, though. When you see the runners going that direction, pay more attention to watering.

    Almost every variety of zoysia requires full sun. There are two I am aware of that tolerate a lot of shade. One is Shadow Turf and the other is Diamond. Here is a picture of Shadow Turf under deep shade of an English walnut tree.

    {{gwi:80716}}

    That lawn had been plugged 18 months earlier on 1 foot centers. The spotty area you see never gets any sunlight. Still you can see that it has expanded from 1-inch plugs to at least 6 inches across. The rest is completely filled in. That tree canopy starts just at about 6 feet up to about 20 feet. It has large leaves and produces very dense shade. The house faces west and the picture was taken at noon. Tall trees across the street block the afternoon sun. This grass is very nice to walk barefoot on.

  • homechicken
    12 years ago

    Just a thought. I have no experience with St. Augustine, but assuming the reason is as you said and just a lack of water, and if you have some areas of healthy grass, couldn't you just cut out a few plugs from there and transplant them to the dead areas? The area where the plugs were taken from should fill back in and the plugs would hopefully spread and fill in the dead areas.

  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    Original Author
    12 years ago

    Actually, over the last few weeks, I've actually made some progress. In the areas where I have not cleared out the layered dead grass, the St. Augustine runners are flourishing. But they aren't rooting! They're just reaching out over the dead grass, presumably desperately trying to find some soil. No, I've watered religiously there. They aren't looking for moist grass, they're looking for moist soil. In the areas where I did remove the layered dead grass, the runners are doing just as well, but they ARE rooting. So I think that answers my question.

    Plugs are an option, and I may do that.

    It's easy to blame this dead grass on not enough watering, but I live in an area where the restrictions on summer watering have been pretty hard. So it's not that I'm unwilling to water, but just that I'm only given so much leeway in how often I can. My whole neighborhood is seeing this problem.

  • nearandwest
    12 years ago

    Plugs aren't just an option, they are the answer.

  • dchall_san_antonio
    12 years ago

    I feel your pain on water restrictions. Beginning today or tomorrow we will go to stage 2 watering restrictions. This means we have 7 hours per week available to us for watering. The catch is that our hours are divided into a 4-hours period 8-midnight) and a 3-hour period (3-6AM). Personally I'm not up at 3AM to turn on the water. Normally my lawn takes 3-5 hours of water in the heat of summer. Three hours I can handle but if it dries out so much I need to go to 5 hours, then I'm into the morning schedule. Several years ago I bought a battery powered timer to turn on the water in the mornings. That worked beautifully and allowed my lawn to survive when many others died.

  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    Original Author
    12 years ago

    Well, it's been a couple of weeks, and I thought I'd give an update.

    In the dead areas that I've cleared, the St. Augustine runners are moving into them, and starting to root well. I hand water those areas every day or two, just to encourage them. Surprisingly, weeds are NOT a problem in these areas. It may be that the layered dead grass was so thick that weed seeds may not have penetrated. If they did, they may not have been able to germinate completely, and essentially died.

    As to plugs, sure, they'd be nice. But given time, healthy St. Augustine does it by itself. In fact, my clumps of live grass in the cleared dead areas have starbursts of runners coming out of them. Yeah, it'll take a year to completely fill back in naturally, but it looks like it'll happen.

    What I have been trying is to take long runners that aren't needed from other parts of the lawn, and try to start them as cuttings in the cleared areas. I mean, a long runner headed out over the sidewalk just needs to go somewhere else!

  • brizzyintx
    12 years ago

    I tried plugging once. It was too much work considering St. Augustine sod is relative cheap. Then again, I don't know how large of an area you're talking about.

    You might be surprised how fast it fills in on its own. We had a 10' diameter pool for a couple of years. The first year we didn't set it up it filled in in about two months. Maybe less.

    Oh, and St. A doesn't mind shade all that much. At the time the first photo was taken, my Bradford Pears were way overgrown, but the grass did just fine. I've since had them cut way back due to them being notorious for splitting in high winds and their proximity to my driveway. This made two distinct differences. The area closest to the house that got the most shade is now a lot denser. But the area by the curb and my neighbor's driveway now gets direct sun most of the day. In the heat of summer I have to hand-water that corner about every other day. You can see in the second picture that area looks a bit stressed.

    {{gwi:90496}}

    {{gwi:93829}}

  • RoxieTexas
    12 years ago

    I just bought a new-to-me house this summer and don't have any experience caring for St. Augustine. I've got lots of dead patches. What are my best options for a healthier lawn this year, given the time of year.

    BTW, I'm on residential water restrictions, as well. Twice a week. Will water fix this? Do I need something else? There is some yellowing, too - or is that just a precursor to dying?

  • dchall_san_antonio
    12 years ago

    1. This topic seems to be answered

    2. Brizzy, nice update pic. Thanks. Y'all should have seen the mess he started with. Both pix are remarkable.

    3. RoxieTexas...please start a new topic to get your question answered. Nobody is going to look here for your issue. They are going to look at the original issue. The short answer to your question, though, is we need more information. Where are you in Texas? How much do you water and how often? How high/low are you mowing? How often do you fertilize and with what? Have you used herbicide or insecticide this year? Your watering may the the solution or it may be the problem. Yellow st aug is not usually a precursor to dying but it might be depending on the answers you give to the questions above.

  • canselmi
    11 years ago

    I know this thread is old, but wanted to give some info in case anyone reads up on this topic.

    To fill in two areas where my St. Aug wasn't growing, I went around the edge of the bare spot (where the grass was still growing) and pulled up any runners the came up easily and re-directed them towards the bare area. You might be surprise how easily you can 'weave' these runners to where you want them to grow.

  • pj_in_austin
    10 years ago

    Daninthedirt, if you are still out there, did you have any luck rooting the st augustine runners? I cut some runners that were hanging of the curb, put them in water with root stimulator with the hope I can use them for thin areas

  • dont-know-squat
    10 years ago

    Hello,
    I opened up an account with this website just so that I could thank you all for your posts on this subject.
    I live in Florida and have St. Aug. grass. I found this link by searching "how to get rid of dead grass in a St. Augustine lawn". I read this entire thread and learned a lot. Special thanks to Dan and dchall for really spelling things out. You guys rock!

  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    Original Author
    9 years ago

    I haven't looked at this thread in several years, but yes, I've had luck rooting the StA runners. What I did was in the bare spots between green growth, which was matted with dead vines, I troweled a bit to cut the old growth and loosen the soil. That lets the runners find soil. A week or two of moisture and sun, and you're good. If the runners can't find soil, they will just keep running, and won't root.

    In some of these StA-less patches, I had Bermuda sprouting, and I pulled all the Bermuda within reach of the StA runners. I keep the Bermuda in, to hold the moisture, until the StA runners get there. Then I pull that Bermuda.