Alkaline soil and Chelated Iron

[AWoo]

Hey everyone,

I'm in Zone 10b (South Florida) and have alkaline soil on my property.   Approx 7.0-7.4 pH on average.   My foxtail/Wodyetia bifurcata is having a difficult time greening up.  I recently started using the 8-2-12+4 Lesco fert with EDTA iron.  But I was wondering if anyone had any luck with Sprint 330 or Sprint 138 in alkaline soils?  Ideally I'd love to apply it 3-4 times a year.  I've heard a foliar spray may get better results than a root drench, but if I do a foliar spray then the chelates aren't needed.

Have you used either the 330 or 138?  If so, what was your rate and how long did it take you to see results?   Thank you so much.

[Looking Glass]

Sprint 138 has EDDHA chelated iron.  This would be your best bet for alkaline soils.  You can also get water soluble EDDHA iron powder in a smaller jar, and put a teaspoon in a watering can and drench the soil.   Foliar iron treatment works on existing foliage, depending on the species, but  is a pain, and only a temporary fix for existing foliage.  Some chelators are toxic to the foliage. 
 

https://www.palmtalk.org/forum/topic/74137-chlorosis-issues/

 

Edited October 18, 2022 by Looking Glass

[AWoo]

Thank you!  I don't mind spending the money, but wanted to check that it was wise before starting.   Do you know if the chelated iron travels to all the fronds or just affects the new growth?

[Looking Glass]

  On 10/18/2022 at 10:49 PM, AWoo said:

Thank you!  I don't mind spending the money, but wanted to check that it was wise before starting.   Do you know if the chelated iron travels to all the fronds or just affects the new growth?

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I hit it hard topically a few time with Ferrous sulfate and Sugar-chelated iron, that created dark green spots and streaks, confirming the iron issue.   The EDDHA drenches seemed to darken the entire plant up a bunch.  I also cut back on watering, which I was overdoing.  
 

 

 

It doesn’t look like it from the pics, but the lack of iron was definitely effecting the growth rate.  After treatment it responded with faster growth and bigger fronds. 
 

https://edis.ifas.ufl.edu/publication/EP551 

Edited October 18, 2022 by Looking Glass

[kinzyjr]

@AWoo Welcome to PalmTalk!

[AWoo]

Thank you all.  Been mostly reading and learning in the forum this year, so now I've got some questions!

Looking Glass, I read your whole thread about that issue.  It was helpful, although it seemed the older fronds greened up spotty, and only through Foliar spray of Fe.  Did the EDDHA chelated iron ever darken the older fronds or did it only affect the new growth?

[Looking Glass]

  On 10/19/2022 at 12:23 AM, AWoo said:

Thank you all.  Been mostly reading and learning in the forum this year, so now I've got some questions!

Looking Glass, I read your whole thread about that issue.  It was helpful, although it seemed the older fronds greened up spotty, and only through Foliar spray of Fe.  Did the EDDHA chelated iron ever darken the older fronds or did it only affect the new growth?

Expand  

The old fronds did seem to green up a bit also, the topical stuff leaves really dark green spots, but the rest of the leaflets seem to get darker too.   How much is from what?…. Hard to say with 100% certainty.  Major changes over 2+ months though.    

[Steve in Florida]

I use 6% EDDHA.  1/8th teaspoon into one gallon makes a 10ppm solution which is more than ten times iron content of the better fertilizers, plus 100% of it is available to the plant in all alkaline soils.

[AWoo]

  On 10/19/2022 at 12:55 AM, Looking Glass said:

The old fronds did seem to green up a bit also, the topical stuff leaves really dark green spots, but the rest of the leaflets seem to get darker too.   How much is from what?…. Hard to say with 100% certainty.  Major changes over 2+ months though.    

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What rate did you use for the EDDHA Fe?

[AWoo]

  On 10/19/2022 at 4:58 AM, Steve in Florida said:

I use 6% EDDHA.  1/8th teaspoon into one gallon makes a 10ppm solution which is more than ten times iron content of the better fertilizers, plus 100% of it is available to the plant in all alkaline soils.

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Did you use one gallon per palm?

[Looking Glass]

  On 10/22/2022 at 11:44 AM, AWoo said:

What rate did you use for the EDDHA Fe?

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I would just put a true teaspoon of the 6% in a 2 gallon watering can and drench the soil all around the palm.  I’d then water that in with a little more water.   The stuff is very soluble.  It Also stains anything like hell, like most iron products.  

[Steve in Florida]

  On 10/22/2022 at 11:45 AM, AWoo said:

Did you use one gallon per palm?

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I would drench with two gallons out to about 16 inches from the trunk.  You should see green-up of new leaves in less than a week unless it's in a really wet spot. 

[Than]

One of the most useful topics I've found (for those of us with alkaline soil)...

May I follow up with a question? Is iron the only mineral/nutrient that is locked in the soil and unavailable in alkaline soils? Or are there other minerals too that become unavailable to the palms if the soil is alkaline?

[Phoenikakias]

  On 10/18/2022 at 11:07 PM, Looking Glass said:

I hit it hard topically a few time with Ferrous sulfate and Sugar-chelated iron, that created dark green spots and streaks, confirming the iron issue.   The EDDHA drenches seemed to darken the entire plant up a bunch.  I also cut back on watering, which I was overdoing.  
 

 

 

It doesn’t look like it from the pics, but the lack of iron was definitely effecting the growth rate.  After treatment it responded with faster growth and bigger fronds. 
 

https://edis.ifas.ufl.edu/publication/EP551 

Expand  

Of course, iron carries oxygen to the cells. I dare say that sufficient iron uptake makes plants more resistant to fungal infection.

[flplantguy]

  On 4/9/2025 at 6:08 PM, Than said:

One of the most useful topics I've found (for those of us with alkaline soil)...

May I follow up with a question? Is iron the only mineral/nutrient that is locked in the soil and unavailable in alkaline soils? Or are there other minerals too that become unavailable to the palms if the soil is alkaline?

Expand  

There are a few of them but it depends on the exact pH.  Others are more available, but the "sweet spot" is the 6.5 to 7 people aim for as most are decent there.  I can't remeber off the top of my head which are less available, but knowing the pH and the mineral content present is helpful to know whats needed.  Compare the soil test and pH to a graph online for nutrient availability of minerals at different pH levels and that will show whats likely lacking. And observation of health too of course.

[flplantguy]

This is a commonly used graph on soil pH and nutrient availability

[Looking Glass]

  On 4/9/2025 at 6:08 PM, Than said:

One of the most useful topics I've found (for those of us with alkaline soil)...

May I follow up with a question? Is iron the only mineral/nutrient that is locked in the soil and unavailable in alkaline soils? Or are there other minerals too that become unavailable to the palms if the soil is alkaline?

Expand  

[Looking Glass]

lol… everyone’s favorite chart.  

[Than]

This chart is so useful, thank you all. 

I tried to gather information about ways to overcome this issue, perhaps by using foliar fertilizers. The consensus seems to be that foliar spraying with nutrients is only a temporary boost. Is there something else one can do?

I live in an area with alkaline soil, full of lime. Yet I see some acidic soil-loving plants thriving in the area. There are several lush, tall and happy Syagrus and Camellias in gardens around here.. I wonder if the garden owners modified the soil (I doubt it) or...?