# Yellow areas - chlorosis?



## PNW_TurfNoob (May 29, 2020)

Hello, I have a northern mix lawn (PRG, FF and a hint KBG) in Western Washington.

I've noticed some yellow areas in my lawn the past few weeks. I applied Vigoro 29-0-4 at the bag rate on 8/19. Had some friends over on 8/22, many jealous comment about how nice the lawn looked (really green, filling in, no yellow areas). Last two weeks I'm noticing this:









I wasn't sure what was going on, so I sprayed propiconazole and applied disease X without much change. I was thinking it could be chlorosis? I have some ferrous sulfate heptahydrate on the way and likely going to spray FAS by the end of the month, but just wanted confirmation that's the right thing to do (doesn't seem like it could hurt with our cool temps).

I was going to wait until Spring for a soil test, but if others think it's necessary I can do one this Fall as well.


----------



## Justmatson (Apr 4, 2020)

@PNW_TurfNoob 
That sure filled in nicely! Good job!

How much nitrogen have you put down this year?
Even though I did kbg it just seems like I can't keep up with how hungry it is for nitrogen. (Could be 1 of your issues) first year lawns needs lots of Nitrogen.

A soil test will definitely help too. I found out in the spring I was low of potassium, sulfur and magnesium. Got lucky and found they make a fertilizer with these nutrients (KMag 0-0-21.5) once I started dropping that I noticed a huge improvement with color.

You doing the N Blitz?

I was doing .5lb/n from urea bi-weekly but have now upped that to 1lb. :nod:


----------



## PNW_TurfNoob (May 29, 2020)

Im planning on putting 1 lb per 1000ft soon and another in Oct. Not sure if the lawn is N hungry or needs some foliar iron (could be both!).


----------



## Justmatson (Apr 4, 2020)

PNW_TurfNoob said:


> Im planning on putting 1 lb per 1000ft soon and another in Oct. Not sure if the lawn is N hungry or needs some foliar iron (could be both!).


Was that Vigoro the one with iron in it?

I used the one with 6% iron and boy did it even green things up but we can't get it in Canada anymore.

Happen to know you soil pH?


----------



## PNW_TurfNoob (May 29, 2020)

The vigoro doesn't have iron in it. It's urea and potassium chloride.

Not sure on the soil ph at this point. Plan is to get a soil test in the Spring.


----------



## zackroof (Oct 27, 2019)

I'm having the same exact issue! So frustrating. Any tell if it's an N issue, watering, or what. I've pulled cores and the roots seem fine. Watering seems a little light, so I think I have some hydrophobic issues, but overall it's OK. At loss here...


----------



## PNW_TurfNoob (May 29, 2020)

zackroof said:


> I'm having the same exact issue! So frustrating. Any tell if it's an N issue, watering, or what. I've pulled cores and the roots seem fine. Watering seems a little light, so I think I have some hydrophobic issues, but overall it's OK. At loss here...


Hopefully one of the super smart people will weigh in and figure it out! I think either way I'm going to spray FAS (mostly just to try it) and I'll report back if it works. I may also do a little test patch where I just spray the ferrous sulfate to figure out if it's just iron or both iron and N deficiency.


----------



## SumBeach35 (Jul 11, 2019)

I have had good luck with spoon feeding of N on my 1 yr or less old backyard that is JG BBU. It will get this splotchy look when it is hungry and needs an app. I prefer to spread XGRN or spray AMS with FEature.


----------



## Justmatson (Apr 4, 2020)

You can rule out if its nitrogen or an iron deficiency or something else. 
Drop a healthy dose of Nitrogen if the yellow stays then try iron. Bi-weekly apps would be better then monthly. Keep Nitrogen in that root zone.
You might have the same issue i had, magnesium deficiency. (Look up magnesium deficiency, its very similar to Nitrogen and iron)

Could just be good 'ol mother nature. Coming out of summer the plant is shedding the weaker leaves and focusing its energy on root development and storing sugars for winter.

@zackroof looking at yours... looks identical to mine in the spring which I know it was low on mg. I'm seeing the same thing with my current reno from spring, but I'm pretty certain its just mother nature doing her thing.

@g-man what do you think?


----------



## PNW_TurfNoob (May 29, 2020)

Great, thanks for the advice everyone. It's pissing outside for the next few days, but I'll get some N and FAS down stat and report back.

I finally read that FAS thread and now I want FeATURE and can't find it just like everyone else. I bought some Lawnstar chelated iron instead, but it's not a great value at all.


----------



## PNW_TurfNoob (May 29, 2020)

Actually just bought some Feature! Looked in your sig @SumBeach35 and bought a bag. Now I have 3 forms of iron on the way... may be experiment time!


----------



## Deadlawn (Sep 8, 2020)

I would get a soil test before applying anything except nitrogen. Keep in mind that you must not apply anything at least 6 weeks before you take a soil sample or you will get false results.

A soil test will also reveal what your soil pH is. Keep in mind that if you soil pH is out of the acceptable range, you can have plenty of nutrients, but they won't be available to the grass. Specifically, if your pH is high, iron will be unavailable and you can have chlorosis regardless of how much iron you have.


----------



## Justmatson (Apr 4, 2020)

I do agree with getting a soil test before applying nutrients. 
I was going to start adding gypsum to help with my clay soil but once I got my soil test I was very high in calcium.

The high pH statement isn't completely accurate. This would only be the case if you were to do soil/ granular apps. 
You can bypass the soil by doing foliar apps, so you can still get iron (or other) into the plant even if you got high pH.


----------



## PNW_TurfNoob (May 29, 2020)

Deadlawn said:


> I would get a soil test before applying anything except nitrogen. Keep in mind that you must not apply anything at least 6 weeks before you take a soil sample or you will get false results.
> 
> A soil test will also reveal what your soil pH is. Keep in mind that if you soil pH is out of the acceptable range, you can have plenty of nutrients, but they won't be available to the grass. Specifically, if your pH is high, iron will be unavailable and you can have chlorosis regardless of how much iron you have.


Thanks for the tip on the soil test. I'll get one submitted stat and hold off on applying iron pending the results. I went with mysoil recent for the front yard, but given the concerns about their resin based assay, I'll submit to Waypoint. Looks like S3M is the test I'll want?


----------



## Deadlawn (Sep 8, 2020)

PNW_TurfNoob said:


> Deadlawn said:
> 
> 
> > I would get a soil test before applying anything except nitrogen. Keep in mind that you must not apply anything at least 6 weeks before you take a soil sample or you will get false results.
> ...


I would only trust the soil tests done by your state cooperative extention. And I wouldn't bother with the kits, they can be way off.


----------



## Justmatson (Apr 4, 2020)

PNW_TurfNoob said:


> Deadlawn said:
> 
> 
> > I would get a soil test before applying anything except nitrogen. Keep in mind that you must not apply anything at least 6 weeks before you take a soil sample or you will get false results.
> ...


Ya thats the go to for most of us.

I wouldn't worry to much about holding off on an iron app if you want to do one. Some of these soil reports ive seen iron is off the chart and they continue to add iron weekly. 
Try an iron app and see what it does.

The soil test would be nice to rule out any deficiency that could be causing your yellowing. Also nice to know the soil pH, organic matter and type of soil you have.


----------



## Deadlawn (Sep 8, 2020)

Justmatson said:


> PNW_TurfNoob said:
> 
> 
> > Deadlawn said:
> ...


Yellowing can be caused by other things besides an iron deficiency. In dicots, an iron deficiency will show as a yellow leaf with green veins. Unfortunately with monocots (grasses), you can't tell this way.

I still say get a soil test before applying anything. I am not a fan of the shotgun approach. Even if nutrients are sufficient, if out of balance, that can cause problems in itself. You don't want to inadvertently end up with a megadose of iron.


----------



## Justmatson (Apr 4, 2020)

[/quote]

Yellowing can be caused by other things besides an iron deficiency. In dicots, an iron deficiency will show as a yellow leaf with green veins. Unfortunately with monocots (grasses), you can't tell this way.

I still say get a soil test before applying anything. I am not a fan of the shotgun approach. Even if nutrients are sufficient, if out of balance, that can cause problems in itself. You don't want to inadvertently end up with a megadose of iron.
[/quote]

Here is an example of of iron chlorosis in grass, as well as nitrogen.

I did comment early that iron might not be the only thing that can cause yellowing in turf grasses. I mention magnesium as well because that was my issue.

I dont believe he plans on spraying a megadose of iron. Even if he was to go heavy it'll turn the grass brown/ black for a bit but then recover. 
A single foliar app isn't going to drastically change anything. It should let him know if it is iron chlorosis or not. 
If you were to add any type of Nitrogen to your fas app and the yellow disappears then it could be either iron or nitrogen deficiency, or both.

https://www.plantanswers.com/yellow_st_augustine.htm


----------



## PNW_TurfNoob (May 29, 2020)

Great thanks for all the input Deadlawn. I also don't like a shotgun approach, but didn't see too much harm in a single application of FAS. Iron seems like a super complicated topic and I don't want to shoot myself in the foot by over applying either.

It looks like our county provides free soil testing through A&L lab in Portland, so that's the route I'll probably take instead of Waypoint. Here's a link to their analytical services fee schedule: http://www.al-labs-west.com/fee-schedule.php?section=Soil%20Analysis

I'll try and get a sample off on Monday and I'll update this thread with the results and recommendations.


----------



## g-man (Jun 15, 2017)

While free, do you know if it is just the simple or the full test?


----------



## PNW_TurfNoob (May 29, 2020)

g-man said:


> While free, do you know if it is just the simple or the full test?


Hi @g-man . According to the website: "We will send your soil samples to A and L Western Laboratories in Portland, OR to test for Nitrogen, Phosphate, Potassium, Magnesium, Calcium, Sodium, Sulfur, Organic Matter, pH, and Cation Exchange Capacity. The laboratory will analyze your soils and provide recommendations specific to your plant needs."

That looks like their S1B test. Does that seem adequate for my situtation?


----------



## zackroof (Oct 27, 2019)

My soil test earlier in the year only revealed a low PH, so I applied 50#/1000 between spring (30#) and just now (20#). We'll see if that helps me at all. I think mine is an N issue, although I've been spoon feeding Carbon X right along (.3 every two weeks). However, may just not be enough. I did a little test as described above (hand spread some Carbon X on a small area yesterday) and it seemed to respond well today. Could just really be hungry.


----------



## PNW_TurfNoob (May 29, 2020)

I think after send off the soil test I'll be due for some N anyways, so we'll see how the yellow spots react to that. We've also had a TON of rain in the past few days, but I'm not sure if that will change much.


----------



## Deadlawn (Sep 8, 2020)

PNW_TurfNoob said:


> g-man said:
> 
> 
> > While free, do you know if it is just the simple or the full test?
> ...


I would say yes.


----------



## g-man (Jun 15, 2017)

@PNW_TurfNoob it doesn't test for iron.


----------



## Deadlawn (Sep 8, 2020)

g-man said:


> @PNW_TurfNoob it doesn't test for iron.


You're right. I missed that.


----------



## PNW_TurfNoob (May 29, 2020)

@g-man LOL, good catch ! It looks like you can add on tests to the free test provided by our county. The "S4" at A&L adds on Zn, Mn, Fe and Cu, so that should cover all my bases right? http://www.al-labs-west.com/fee-schedule.php?section=Soil%20Analysis

This is the lab that the WSU extension recommends. With the potential for USPS delays I'd rather keep it close if possible.


----------



## g-man (Jun 15, 2017)

AL is a good lab.


----------



## PNW_TurfNoob (May 29, 2020)

Thanks @g-man Glad to hear that that A&L gets your vote of confidence. Do you see any problem with an app of FAS and continuing my Fall N blitz pending the the results? I was going to put down more Vigoro 29-0-4 this week. I'm 5 weeks from my last N and would like to apply soon.


----------



## g-man (Jun 15, 2017)

After you sample, throw anything you want.


----------



## Justmatson (Apr 4, 2020)

Do you use an edge guard on your spreader?


----------



## PNW_TurfNoob (May 29, 2020)

Justmatson said:


> Do you use an edge guard on your spreader?


Actually I was using a crappy old scotts spreader that had edge guard and I used for seeding and my fert apps thru July. I was getting really uneven applications. In August, I upgraded to an ECHO RB-60 and only use it's edge guard along the patio. I had pretty consistent coverage with my August application of Vigoro, but have some barespots and stripes to work on.

You can see this in the pic from July:


----------



## Justmatson (Apr 4, 2020)

Ya i remember that.

Reason I ask is looking at some of those pics a lot of the edges are more green then the center. Lends me to think more fertilizer was applied.

I still think its deficient in something. Your soil test will clear this up, hopefully. :shock:


----------



## PNW_TurfNoob (May 29, 2020)

Quick update: I sprayed Lawn Star chelated iron at the 4oz per 1000ft2 rate on 9/27 after submitting my soil test. I didn't really get much of a green up.

I've gone over the lawn with a rake to clear out some of the yellow crap.




I went throw the yellow areas on my hands and knees and pulled a plant that seems to best represent the problem. Oldest leaves yellowing with nice green growth on the new leaves. Not sure if this is helpful for anyone? I am very glad to have a soil test pending! I'm going to hold off on applying any fert on the back until I get the results from A&L (they said likely Tues) and do my core aeration and Prodiamine this weekend.


----------



## g-man (Jun 15, 2017)

Do nitrogen.

I would not core aerate a lawn with issues.


----------



## Deadlawn (Sep 8, 2020)

g-man said:


> Do nitrogen.
> 
> I would not core aerate a lawn with issues.


Curious to know why not to core aerate a lawn with issues?


----------



## g-man (Jun 15, 2017)

Core aeration tears the roots, adds surface area for the soil to dry (holes) and covers the leaves with the cores/dirt. Why stress it more? Purdue suggest to do it when the turf is actively growing.

The new leaf shows no issues, but the older one does. To me this is a sign that the grass is not growing at a good rate. Feed it fast nitrogen and let's see how it responds.


----------



## PNW_TurfNoob (May 29, 2020)

@g-man great advice! The grass is still growing. I'm getting clippings when I mow twice a week, but it certainly doesn't look vigorous...

I'll apply it some N next week after I get the soil test results. I'll update the thread after I see a response.

Do you think Prodiamine would still be okay?


----------



## Deadlawn (Sep 8, 2020)

g-man said:


> Core aeration tears the roots, adds surface area for the soil to dry (holes) and covers the leaves with the cores/dirt. Why stress it more? Purdue suggest to do it when the turf is actively growing.


Makes sense.



g-man said:


> The new leaf shows no issues, but the older one does. To me this is a sign that the grass is not growing at a good rate.


Also makes sense as plants will sacrifice older growth when they are stressed.


----------



## g-man (Jun 15, 2017)

@PNW_TurfNoob the soil test results will not influence your need for nitrogen. The sooner you apply the N, the sooner we can see a response.


----------



## PNW_TurfNoob (May 29, 2020)

@g-man sounds good. I'll get some N down as soon as possible. I have ammonium sulfate and a 29-0-4 that is 21% urea). Any preference between the two?

Also, what do you guys think about applying prodiamine at this point? I'm not sure if prodiamine stresses the turf in any way.


----------



## BrainBailey (Nov 20, 2019)

@PNW_TurfNoob This might be a very dumb question since you're in Seattle, but how long has it been since you've had substantial rainfall? I was having very similar issues with my lawn, but the past few days we've had substantial rainfall in the Midwest, and my lawn has really started to turn the corner now. I did apply some chelated iron too, but don't think it had a very noticeable affect. If you haven't had some good rain yet, maybe wait a little longer before trying to make more corrections?


----------



## g-man (Jun 15, 2017)

Ams


----------



## Justmatson (Apr 4, 2020)

I would not put down any Prodiamine. Any poa a would have germinated by now and is currently growing. 
If properly applied it shouldn't stress your grass anymore.

With the ams, make sure you water it in. Its higher in salt content then urea. Im seeing a few guys burn their lawns this fall with it.


----------



## PNW_TurfNoob (May 29, 2020)

@BrainBailey I know we get a ton of rain here LOL, but actually not that much in Summer. When I pulled the cores for the soil sample it all looked moist. It was a decent September for rain too. We've had 1.5" of rain in September and I didn't see any change in the yellowing after a pretty decent week of rain last week. I've been also watering that part of the yard when it's not raining.

@g-man and @Justmatson , thanks for the tips on AMS. I've not used it before and will be sure to water it in afterward. I've read about the potential for burning.


----------



## zackroof (Oct 27, 2019)

BrainBailey said:


> @PNW_TurfNoob This might be a very dumb question since you're in Seattle, but how long has it been since you've had substantial rainfall? I was having very similar issues with my lawn, but the past few days we've had substantial rainfall in the Midwest, and my lawn has really started to turn the corner now. I did apply some chelated iron too, but don't think it had a very noticeable affect. If you haven't had some good rain yet, maybe wait a little longer before trying to make more corrections?


Ditto here in NE Mass. I was struggling with the yellowing and the recent rains really helped things along, in addition to a little boost of more N. Weird considering I was watering sufficiently - as determined by core pulls.


----------



## Justmatson (Apr 4, 2020)

zackroof said:


> BrainBailey said:
> 
> 
> > @PNW_TurfNoob This might be a very dumb question since you're in Seattle, but how long has it been since you've had substantial rainfall? I was having very similar issues with my lawn, but the past few days we've had substantial rainfall in the Midwest, and my lawn has really started to turn the corner now. I did apply some chelated iron too, but don't think it had a very noticeable affect. If you haven't had some good rain yet, maybe wait a little longer before trying to make more corrections?
> ...


Nothing compares to mother nature. Rain is far superior to us irrigating.


----------



## BrainBailey (Nov 20, 2019)

@Justmatson Gotta love those free micros!


----------



## PNW_TurfNoob (May 29, 2020)

Got the soil analysis report back from A&L Western:



Looks like it is N and dolomite lime for the Fall! So much for my iron theory!

Really want to thank @Deadlawn @Justmatson and of course @g-man for the sage wisdom of getting a soil test instead of just spray and pray. :beer:

For the pH/lime issue, I'll tackle that this weekend. It looks like the lab recommends a max of 50lb/1000sqft of dolomite, so I'll have to keep working on that next year since I'm 160lbs/1000k sqft behind if I'm reading the report correctly.

I wish I had had more time to devote to N this past year and I'm hoping I can make some of it up this Fall. It looks like I can use the 29-0-4 I have unless others feel like AMS is the better route. I'll apply in about 3 weeks or so.

They also recommended P and K, but I think I'll just stick with N for the Fall and do another soil test next Spring for a complete 2021 plan. I understand that the turf will use P and K with the N, but I think I should be have sufficient P and K for to cover my AMS app this past weekend and one more N app this Fall.

I'll post an updated pic after I get a chance to evaluated the response from the AMS. It's still hard for me to believe I got behind on N this year since this is the most I've ever fertilzed a lawn!!


----------



## g-man (Jun 15, 2017)

You need calcitic lime. Since you have a young lawn, wait until November for the lime. Start sourcing it and look for the non fast acting one if possible.

Your P is high and your K is at a good level, just maintain it.

Continue with AMS weekly at 0.25lb of N/ksqft. Save the 29-0-4 for May 2021.


----------



## PNW_TurfNoob (May 29, 2020)

@g-man thanks for suggestion. A&L recommended dolomite lime (something to do with the Mg%). Any reason you recommend calcitic lime in place of dolomite lime?


----------



## g-man (Jun 15, 2017)

Your Mg is at a good level. Adding calcitic will increase the calcium and get you a "better" calcium to Mg ratio.


----------



## Deadlawn (Sep 8, 2020)

g-man said:


> Your Mg is at a good level. Adding calcitic will increase the calcium and get you a "better" calcium to Mg ratio.


^^^This.^^^

I have a hard time understanding why they are recommending dolomite when your Mg is at a normal level and your calcium is low. Dolomite could raise your Mg too high. Use calcitic lime.


----------



## PNW_TurfNoob (May 29, 2020)

@Deadlawn thanks for seconding the recommendation to stay away from dolomite. I read about Mg in the soil remediation thread and it looks like high Mg is something I want to avoid. A&L stated in the handout that came along with the results that they "generally recommend" dolomite lime if the Mg saturation of the soil is less than 15% and mine was 14.1%.

I was able to find a pelletized calcium carbonate Lime (Pro-Pell-It!) at Site-One that I'm planning to use. It looks like it is "slow lime" since the rate they recommend is 50lb/1000kft2. I need to add 160lb/1000kft2 eventually, but it's going to take a growing seasons and only plan to apply 50 this Nov.

The good news is that I'm already starting to see a green up since using the AMS. There is still a lot of yellow material in there, but the grass is darkening up and growing again. Guess I just got behind on N and will do my best to make up for this Fall.


----------



## SOLARSUPLEX (Aug 4, 2020)

You've been busy over there! I wish we were just a hair closer and I could mimic the needs from the results of your soil test. Seems the A&L test was better than what you'd gotten previously. I'll follow that path to see what nutrients im looking for. Glad things are greening up!


----------



## Deadlawn (Sep 8, 2020)

PNW_TurfNoob said:


> @Deadlawn thanks for seconding the recommendation to stay away from dolomite. I read about Mg in the soil remediation thread and it looks like high Mg is something I want to avoid. A&L stated in the handout that came along with the results that they "generally recommend" dolomite lime if the Mg saturation of the soil is less than 15% and mine was 14.1%.
> 
> I was able to find a pelletized calcium carbonate Lime (Pro-Pell-It!) at Site-One that I'm planning to use. It looks like it is "slow lime" since the rate they recommend is 50lb/1000kft2. I need to add 160lb/1000kft2 eventually, but it's going to take a growing seasons and only plan to apply 50 this Nov.
> 
> The good news is that I'm already starting to see a green up since using the AMS. There is still a lot of yellow material in there, but the grass is darkening up and growing again. Guess I just got behind on N and will do my best to make up for this Fall.


50 lbs. lime per 1000 sq ft is the max generally recommended at any one time. My cooperative extension recommended 100 lbs/1000 sq ft and said to apply 50 lbs in fall and the other 50 lbs in the spring.


----------



## PNW_TurfNoob (May 29, 2020)

SOLARSUPLEX said:


> You've been busy over there! I wish we were just a hair closer and I could mimic the needs from the results of your soil test. Seems the A&L test was better than what you'd gotten previously. I'll follow that path to see what nutrients im looking for. Glad things are greening up!


I'm always busy, just finally posting about it again! :lol: I think I'm going to stick with A&L lab. They are the lab that King County's Conservation District recommends.


----------



## PNW_TurfNoob (May 29, 2020)

@Deadlawn thanks for the info. That was actually my plan to split things up over Fall and Spring. I may need to go 50 lbs in Fall 20, Spring 21 and Fall 21. I'll do another soil test next Spring prior to applying however. I have another area that I'll be planting a new lawn on next year and my understanding is that you can apply more lime to soil that doesn't have turf on it yet.


----------

