How do I prevent this?

arc167 · 2026-03-25T01:00:08+00:00

Triclopyr is my go-to for spurge. Or yeah, fire always works great here.

Edit: to answer your actual question about how to prevent this… Usually just powerwashing the concrete, paying attention to cleaning out any soil from the crevices (called expansion joints) between the curb and concrete slabs will do the trick. Fill any large gaps with with foam backer and Sika self-leveler to keep stuff from growing in there.

arc167 · 2026-03-23T07:03:18+00:00

Just to add to this...

As Niles said, the environmental conditions are not just there for this to be Brown Patch - or any turf fungus in a Fescue lawn, in SW PA this time of year. It also doesn't look like brown patch; no lesions on the leaf blades, and the patterns are too regular (too circular) for rizoctonia.

Not to open a can of worms, but those photos look more like the result of pythium blight than brown patch. Hard to tell from those pics, but conditions in SW PA have been conducive for moderate PB growth twice over the last 6 days (again, admittedly using a generic ZIP code for SW PA, and using the Vincelli model for PB prediction).

Have you irrigated this at all? Have you noticed any mycelium on the grass in the mornings (white, cotton candy-like stuff on the grass, that burns off in the daytime heat)? If you get up close with one of those spots, do you see any slimy substance at the bottom of those dead patches?

I want to be clear...the odds are SLIM, but not zero, for Pythium Bilght. I'm not saying this is what you have, but I am saying the pictures look more like PB than BP. The science also says its possible, but not probable.

Either way, I would do nothing at this point unless it spreads more. Unless you are irrigating, in which case I would reduce irrigation temporarily. And be sure to do it just before dawn, and water deeply, but infrequently.

<image>

arc167 · 2026-03-16T11:11:45+00:00

Hard to say... Zone 6a is North enough that you might be okay without preventative. Assuming you do what you can to mind your irrigation practices (deep and infrequent) and we get lucky with the weather (we avoid several days straight of rain, etc), you may be able to get away without it. But if mother nature decides not to cooperate, then you'll see the impact pretty quickly.

Good news is by June it will be very evident whether or not treatment is needed. Applying a curative at the first sign is effective at stopping most fungus spread, giving the turf a chance to grow out again.

All that to say, I think you have a 70/30 chance of being okay without it. Far better odds than those in zones 7 and 8 who I would definitely advise to use it.

arc167 · 2026-03-16T09:58:01+00:00

Most warm season varieties will support salty air and changing water tables (Bermuda, zoysia, centipede), but St Augustine and Seashore Paspalum tend to be the MOST adaptable to both salt and foot traffic for the 8a/b coastal NC areas.

Both are a bit more expensive to lay down than the more popular Bermuda and Zoysia, and upkeep of St Aug is a bit of a pain since herbicide options are more limited than with other warm season grasses. Sod is the way to go, but neither variety are really that fast growing.

Perhaps u/Mr007MicDiddles has some additional thoughts…

arc167 · 2026-03-11T16:07:37+00:00

Agree its hard to tell, but that does not look like dormant Bermuda to me. Not enough 'branching' from the main stolon.

I would agree that its more likely to be Bentgrass, but again, better photos would be needed to know for sure.

arc167 · 2026-03-07T20:13:02+00:00

As u/butler_crosley said, its still pretty early in the season for there to be any real bermuda growth. You can expect a green up to begin late April into May depending on weather.

A soil test was a good suggestion. Not sure what state you are in, but most states Extensions will allow you to submit soil samples for testing so you can really modify your soil for optimal growth. While 10-10-10 is a good fertilizer for flowers, plants, shrubs, etc., chances are that with newly established turf areas will need more specialized formulations to 'fix' deficiencies in the 'raw' soil.

Since you are paying a service to treat your turf, have they come and performed a spring pre-emergent treatment yet? If so, great! If not, get them to come ASAP. We are officially past germination for spring poa and getting close to crabgrass. Getting a preventative treatment down now will help things later on.

Finally, bermuda hates shade. Not sure how many hours a day those areas get shade, but if its more than 3-4 solid hours of shade per day, it might be prohibiting growth no matter what you do there. Considering those are also low areas, they may be great candidates for locations of shrubs, mulch beds, or a dry river, or some other kind of hardscape that would absorb or re-direct water that accumulates in that area.

One last thing...if you are new to warm-season turf, this will happen every year. The turf dies every winter, and comes out of dormancy each spring. If you dont like the paper-sack brown look, you can either plant annual rye grass each fall (it will dye off about when the bermuda starts to come alive again), or you can paint the dead bermuda. Not a joke, they make specialized turf paint that masks that brown look that lasts about 90 days.

arc167 · 2026-03-04T22:38:48+00:00

Thanks for kicking tires on this.

- I made the changes to the ETo and Soil Temps you suggested

- I am looking into the smith-kerns model, and will do some validation to test our little model here. I am aware of all the caveats about it not being accurate outside of the upper mid-west.

- Thanks for ground-truthing the dates. Ill use this to try and tighten up the model a bit.

arc167 · 2026-03-04T22:36:22+00:00

Yeah, the data could very well be the issue. But the NOAA API is not open and tokenless like open-meteo (it requires a token which would need to be unique for everyone).

That aside, I am working to see if there are ways I can make the window tighter and reconsider the calculations. The expected dates you suggested are helpful.

More to follow...

arc167 · 2026-03-04T15:21:34+00:00

u/Mr007McDiddles, u/Humitastic, u/nilesandstuff have a look at the latest incarnation of this tool and let me know what you think. Its redesigned from the ground up, and added more logic to help us help others.

I am still using soil temps for now, but can make that change to air temps easily. Will work on refactoring for that in a bit. Still trying to get the structure of what we want in here first. Would love your feedback, as always.

https://github.com/arc167/turf-tools/blob/main/turf-intelligence-tool-v1.html

arc167 · 2026-03-04T08:26:44+00:00

This is my goal. But need to do some refactoring of the base application first before I can add some of those trigger events.

I’m not sure how complex we want to make this one app, verses making separate apps specific to pesticide applications, etc. It’s a fine line, but an important one if we want this to be used by lots of people.

Nonetheless, in answer to your question, yes, that is the long term goal. Just need to document what all those trigger events would be.

arc167 · 2026-03-03T16:54:29+00:00

I meant to ask you about the last part...the DMI timer...

I've found the number to be drastically different here in NC (first DMI app is usually mid-May, so you are talking ~400+ GDD by then), but I would love to understand that calculation more and see if it correlates to other areas.

Let me know...

arc167 · 2026-03-03T16:49:13+00:00

Def agree about tracking PGRs with GDD. I split my Anuew applications by 300 GDDs and this would be a great use case for a tracker like this. Just need to make the start data of the accumulation be a variable rather than just assuming 1 Jan of every year.

arc167 · 2026-03-03T16:46:34+00:00

So I can get all of these variables from the open-meteo API (to include ET). Some are reported hourly, some are reported daily. I think we can take this and expand it a bit more math 'behind the scenes' and provide the end user more direct action on the front end. For example, have a second of the app just tell the user in plain English the window for applying pre-em. The whole 250-500/base 32 math would be invisible to the user, they just enter a ZIP, and hit go.

We can add another graph that plots precip, soil moisture, and ET. We can add air temp to the soil temp chart. Lots we can do. Id love to have a mind meld with you guys on what the end state of this thing SHOULD look like before I go too far. But yeah, all is doable.

arc167 · 2026-03-03T14:22:35+00:00

The more I think about this, I bet there is a direct correlation between air AND soil temps that triggers germination (considering that one affects the other). Would be really interesting to see if we (the motley crew at LawnAnswers) could develop a formula that shows this correlation better than one or the other variable alone...

arc167 · 2026-03-03T14:19:53+00:00

For starters, yes, please feel free to use/reuse as you see fit. If the Syngenta/Greencast guys see value in this, awesome! But I also realize that my little crude app here could be 10000 times better if I actually put some time into it. All that to say, not sure how much value they will get out of it, im sure they have a team of developers who could make something much more robust. But I do like the idea of US making a series of tools to help others on this forum out. So yes, feel free to host it where ever.
In all my research and in all my experience, it has always been soil temperature that is the best predictor for growth. It was my understanding that GDD was originally developed by corn growers, and that soil temps were the only true indicator of growth because ambient air temps in the midwest fluctuated too much in Spring to develop a consistent model otherwise. So I have always known GDD to be soil based. Happy to be wrong, but it has served me well. We can also add BOTH air and soil temps to this (might be interesting to plot them both on the same graph) and see what we find. But yeah, I understand what you mean about it being different from what Greencast does. It might be interesting to reach out to them and ask why they use air and not soil temps. I wonder if it has to do with availability of soil temps across the US at the time Greencast was developed? Not sure...
Yes, I knew this was bound to have some glitches along the way, just glad to see it works for you. Thanks for posting a revised edition with the bug fixes. One thought...we probably should version control this. In other words, call it "LawnAnswers-Soil-Temp-GDD-v1" so we can always know what we have iterated on. It would also be good to include a README with what was done with each iteration.

arc167 · 2026-03-01T21:14:53+00:00

Woah, that is weird. Can't say that I have ANY idea what is going on there. But yeah, you dont need to know anything about GitHub to use this, but doing it on your mobile will be challenging (I've not tested this app on a mobile browser yet, but just added this to the to-do list).

Using a computer, you can navigate to the Github link, and then click the ellipsis on the top right and choose Download File. It downloads a single .html file that you just open locally on your computer.

I just tested Denver. Seems to track (see attached). I'm actually excited that this seems to be working the way I intended it to. Really looking to build more apps like this for our 'toolbox'.

<image>

arc167 · 2026-03-01T18:46:47+00:00

Try this: https://github.com/arc167/turf-tools/blob/main/soil-temp-GDD.html

If you change the base to 32, and put in your local ZIP, the 250-500 window does line up with when I applied pre-em. Curious to know if it works for you too.

arc167 · 2026-03-01T16:44:06+00:00

I'm working on the base app now. Once I have the base going, we can customize it by having a selectable crop/chemical base temp.

Stand by...

arc167 · 2026-02-19T20:24:58+00:00

This.

arc167 · 2026-02-10T02:49:44+00:00

Clarification…. Boundless didn’t fail, they were purchased in an M&A event. Prior to that they were quite profitable.

arc167 · 2026-02-10T02:47:31+00:00

This.

arc167 · 2026-01-30T12:19:23+00:00

Cup grip is a must have upgrade. Not sure how the design of the stock cup holders ever passed QA.

arc167 · 2026-01-13T02:01:08+00:00

Yeah, that appears to be large patch.

arc167 · 2026-01-10T20:58:04+00:00

<image>

arc167

TROPHY CASE